在Android應用程序中單擊CardView不會打開“活動”，而導致應用程序崩潰

Question

我是Android開發的新手，剛開始用Java啟動了我的第一個Android應用程序。 我的應用程序是有關單位換算的，它由卡片視圖組成，這些卡片視圖顯示要轉換其單位的數量。 單擊CardView時，應將用戶定向到進行轉換的部分，但是可以看到，單擊CardView時，應用程序崩潰。 請提出針對該問題的適當補救措施。 MainActivity.java代碼-包com.example.unitconversionapp;

import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.view.View;

import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;
import androidx.cardview.widget.CardView;

public class MainActivity extends AppCompatActivity {

    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    void setActivityTemperature(View view) {
        CardView card_view = findViewById(R.id.temperature_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityArea(View view) {
        CardView card_view = findViewById(R.id.area_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityTime(View view) {
        CardView card_view = findViewById(R.id.time_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivitySpeed(View view) {
        CardView card_view = findViewById(R.id.speed_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityWeight(View view) {
        CardView card_view = findViewById(R.id.weight_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityEnergy(View view) {
        CardView card_view = findViewById(R.id.energy_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityAngle(View view) {
        CardView card_view = findViewById(R.id.angle_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityLength(View view) {
        CardView card_view = findViewById(R.id.length_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityVolume(View view) {
        CardView card_view = findViewById(R.id.volume_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityCurrency(View view) {
        CardView card_view = findViewById(R.id.currency_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }
}

XML代碼-

    <?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:textAlignment="center"
    tools:context=".MainActivity">

    <androidx.cardview.widget.CardView
        android:id="@+id/speed_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivitySpeed"
        app:cardBackgroundColor="@color/colorAccent"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/volume_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Speed" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/angle_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityAngle"
        app:cardBackgroundColor="@color/colorPrimary"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/area_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView2"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Angle" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/time_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityTime"
        app:cardBackgroundColor="@android:color/holo_purple"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:cardMaxElevation="25dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/angle_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView3"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Time" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/volume_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityVolume"
        app:cardBackgroundColor="@color/colorPrimaryDark"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/currency_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView4"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Volume" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/area_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityArea"
        app:cardBackgroundColor="@android:color/holo_red_light"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/length_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView5"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Area" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/currency_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityCurrency"
        app:cardBackgroundColor="@android:color/holo_red_dark"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/weight_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView6"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Currency" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/weight_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="19dp"
        android:onClick="setActivityWeight"
        app:cardBackgroundColor="@android:color/holo_green_light"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/my_toolbar">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView7"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Weight" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.appcompat.widget.Toolbar
        android:id="@+id/my_toolbar"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:background="@color/colorToolbar"
        android:minHeight="?attr/actionBarSize"
        android:theme="?attr/actionBarTheme"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:subtitleTextColor="#FFFFFF"
        app:title="Unit Conversion"
        app:titleTextColor="#FFFFFF" />

    <androidx.cardview.widget.CardView
        android:id="@+id/temperature_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="19dp"
        android:onClick="setActivityTemperature"
        app:cardBackgroundColor="@android:color/holo_orange_dark"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/my_toolbar">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:onClick="setActivityTemperature">

            <TextView
                android:id="@+id/textView8"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Temperature" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/length_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityLength"
        app:cardBackgroundColor="@android:color/holo_blue_dark"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/temperature_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView9"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Length" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/energy_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityEnergy"
        app:cardBackgroundColor="?attr/colorError"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/speed_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView10"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Energy" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

</androidx.constraintlayout.widget.ConstraintLayout>

錯誤堆棧跟蹤由-

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.unitconversionapp, PID: 22617
    java.lang.IllegalStateException: Could not find method setActivityWeight(View) in a parent or ancestor Context for android:onClick attribute defined on view class androidx.cardview.widget.CardView with id 'weight_card'
        at android.view.View$DeclaredOnClickListener.resolveMethod(View.java:6302)
        at android.view.View$DeclaredOnClickListener.onClick(View.java:6259)
        at android.view.View.performClick(View.java:7448)
        at android.view.View.performClickInternal(View.java:7425)
        at android.view.View.access$3600(View.java:810)
        at android.view.View$PerformClick.run(View.java:28305)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)

Answer 1

我是Android開發的新手，剛開始用Java啟動了我的第一個Android應用程序。 我的應用程序是有關單位換算的，它由卡片視圖組成，這些卡片視圖顯示要轉換其單位的數量。 單擊CardView時，應將用戶定向到進行轉換的部分，但是可以看到，單擊CardView時，應用程序崩潰。 請提出針對該問題的適當補救措施。 MainActivity.java代碼-包com.example.unitconversionapp;

import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.view.View;

import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;
import androidx.cardview.widget.CardView;

public class MainActivity extends AppCompatActivity {

    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    void setActivityTemperature(View view) {
        CardView card_view = findViewById(R.id.temperature_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityArea(View view) {
        CardView card_view = findViewById(R.id.area_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityTime(View view) {
        CardView card_view = findViewById(R.id.time_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivitySpeed(View view) {
        CardView card_view = findViewById(R.id.speed_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityWeight(View view) {
        CardView card_view = findViewById(R.id.weight_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityEnergy(View view) {
        CardView card_view = findViewById(R.id.energy_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityAngle(View view) {
        CardView card_view = findViewById(R.id.angle_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityLength(View view) {
        CardView card_view = findViewById(R.id.length_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityVolume(View view) {
        CardView card_view = findViewById(R.id.volume_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityCurrency(View view) {
        CardView card_view = findViewById(R.id.currency_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }
}

XML代碼-

    <?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:textAlignment="center"
    tools:context=".MainActivity">

    <androidx.cardview.widget.CardView
        android:id="@+id/speed_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivitySpeed"
        app:cardBackgroundColor="@color/colorAccent"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/volume_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Speed" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/angle_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityAngle"
        app:cardBackgroundColor="@color/colorPrimary"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/area_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView2"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Angle" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/time_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityTime"
        app:cardBackgroundColor="@android:color/holo_purple"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:cardMaxElevation="25dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/angle_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView3"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Time" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/volume_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityVolume"
        app:cardBackgroundColor="@color/colorPrimaryDark"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/currency_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView4"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Volume" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/area_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityArea"
        app:cardBackgroundColor="@android:color/holo_red_light"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/length_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView5"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Area" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/currency_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityCurrency"
        app:cardBackgroundColor="@android:color/holo_red_dark"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/weight_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView6"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Currency" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/weight_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="19dp"
        android:onClick="setActivityWeight"
        app:cardBackgroundColor="@android:color/holo_green_light"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/my_toolbar">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView7"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Weight" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.appcompat.widget.Toolbar
        android:id="@+id/my_toolbar"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:background="@color/colorToolbar"
        android:minHeight="?attr/actionBarSize"
        android:theme="?attr/actionBarTheme"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:subtitleTextColor="#FFFFFF"
        app:title="Unit Conversion"
        app:titleTextColor="#FFFFFF" />

    <androidx.cardview.widget.CardView
        android:id="@+id/temperature_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="19dp"
        android:onClick="setActivityTemperature"
        app:cardBackgroundColor="@android:color/holo_orange_dark"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/my_toolbar">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:onClick="setActivityTemperature">

            <TextView
                android:id="@+id/textView8"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Temperature" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/length_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityLength"
        app:cardBackgroundColor="@android:color/holo_blue_dark"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/temperature_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView9"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Length" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/energy_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityEnergy"
        app:cardBackgroundColor="?attr/colorError"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/speed_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView10"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Energy" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

</androidx.constraintlayout.widget.ConstraintLayout>

錯誤堆棧跟蹤由-

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.unitconversionapp, PID: 22617
    java.lang.IllegalStateException: Could not find method setActivityWeight(View) in a parent or ancestor Context for android:onClick attribute defined on view class androidx.cardview.widget.CardView with id 'weight_card'
        at android.view.View$DeclaredOnClickListener.resolveMethod(View.java:6302)
        at android.view.View$DeclaredOnClickListener.onClick(View.java:6259)
        at android.view.View.performClick(View.java:7448)
        at android.view.View.performClickInternal(View.java:7425)
        at android.view.View.access$3600(View.java:810)
        at android.view.View$PerformClick.run(View.java:28305)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)

Answer 2

我是Android開發的新手，剛開始用Java啟動了我的第一個Android應用程序。 我的應用程序是有關單位換算的，它由卡片視圖組成，這些卡片視圖顯示要轉換其單位的數量。 單擊CardView時，應將用戶定向到進行轉換的部分，但是可以看到，單擊CardView時，應用程序崩潰。 請提出針對該問題的適當補救措施。 MainActivity.java代碼-包com.example.unitconversionapp;

import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.view.View;

import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;
import androidx.cardview.widget.CardView;

public class MainActivity extends AppCompatActivity {

    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    void setActivityTemperature(View view) {
        CardView card_view = findViewById(R.id.temperature_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityArea(View view) {
        CardView card_view = findViewById(R.id.area_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityTime(View view) {
        CardView card_view = findViewById(R.id.time_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivitySpeed(View view) {
        CardView card_view = findViewById(R.id.speed_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityWeight(View view) {
        CardView card_view = findViewById(R.id.weight_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityEnergy(View view) {
        CardView card_view = findViewById(R.id.energy_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityAngle(View view) {
        CardView card_view = findViewById(R.id.angle_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityLength(View view) {
        CardView card_view = findViewById(R.id.length_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityVolume(View view) {
        CardView card_view = findViewById(R.id.volume_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }

    void setActivityCurrency(View view) {
        CardView card_view = findViewById(R.id.currency_card);
        card_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do whatever you want to do on click (to launch any fragment or activity you need to put intent here.)
                Intent intent = new Intent(MainActivity.this, ActivityTemperature.class);
                startActivity(intent);
            }
        });
    }
}

XML代碼-

    <?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:textAlignment="center"
    tools:context=".MainActivity">

    <androidx.cardview.widget.CardView
        android:id="@+id/speed_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivitySpeed"
        app:cardBackgroundColor="@color/colorAccent"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/volume_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Speed" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/angle_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityAngle"
        app:cardBackgroundColor="@color/colorPrimary"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/area_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView2"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Angle" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/time_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityTime"
        app:cardBackgroundColor="@android:color/holo_purple"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:cardMaxElevation="25dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/angle_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView3"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Time" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/volume_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityVolume"
        app:cardBackgroundColor="@color/colorPrimaryDark"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/currency_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView4"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Volume" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/area_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityArea"
        app:cardBackgroundColor="@android:color/holo_red_light"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/length_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView5"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Area" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/currency_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityCurrency"
        app:cardBackgroundColor="@android:color/holo_red_dark"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/weight_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView6"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Currency" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/weight_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="19dp"
        android:onClick="setActivityWeight"
        app:cardBackgroundColor="@android:color/holo_green_light"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/my_toolbar">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView7"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Weight" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.appcompat.widget.Toolbar
        android:id="@+id/my_toolbar"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:background="@color/colorToolbar"
        android:minHeight="?attr/actionBarSize"
        android:theme="?attr/actionBarTheme"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:subtitleTextColor="#FFFFFF"
        app:title="Unit Conversion"
        app:titleTextColor="#FFFFFF" />

    <androidx.cardview.widget.CardView
        android:id="@+id/temperature_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="19dp"
        android:onClick="setActivityTemperature"
        app:cardBackgroundColor="@android:color/holo_orange_dark"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/my_toolbar">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:onClick="setActivityTemperature">

            <TextView
                android:id="@+id/textView8"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Temperature" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/length_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityLength"
        app:cardBackgroundColor="@android:color/holo_blue_dark"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/temperature_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView9"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Length" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/energy_card"
        android:layout_width="200dp"
        android:layout_height="110dp"
        android:layout_marginTop="12dp"
        android:onClick="setActivityEnergy"
        app:cardBackgroundColor="?attr/colorError"
        app:cardCornerRadius="25dp"
        app:cardElevation="25dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/speed_card">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/textView10"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="Energy" />
        </RelativeLayout>
    </androidx.cardview.widget.CardView>

</androidx.constraintlayout.widget.ConstraintLayout>

錯誤堆棧跟蹤由-

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.unitconversionapp, PID: 22617
    java.lang.IllegalStateException: Could not find method setActivityWeight(View) in a parent or ancestor Context for android:onClick attribute defined on view class androidx.cardview.widget.CardView with id 'weight_card'
        at android.view.View$DeclaredOnClickListener.resolveMethod(View.java:6302)
        at android.view.View$DeclaredOnClickListener.onClick(View.java:6259)
        at android.view.View.performClick(View.java:7448)
        at android.view.View.performClickInternal(View.java:7425)
        at android.view.View.access$3600(View.java:810)
        at android.view.View$PerformClick.run(View.java:28305)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7656)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)