在startActivity（）期间“应用程序已停止”

Question

I am trying to load a new activity with a button click but I have some problems. After the click I get an error: "Application was stopped..."

This is my application:

LoginPage.java:

public class LoginPage extends ActionBarActivity {

    private Button loginButton;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login_page);

        loginButton = (Button)findViewById(R.id.loginButon);
        loginButton.setOnClickListener(new LoginButtonListener());
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.login_page, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }


    private class LoginButtonListener implements View.OnClickListener {
        @Override
        public void onClick(View v) {

            Intent intent = new Intent(LoginPage.this, MasterUserActivity.class);
            startActivity(intent);

        }
    }
}

MasterUserActivity.java:

public class MasterUserActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.master_user);

        Toast toast = Toast.makeText(getApplicationContext(), "It works :)", Toast.LENGTH_LONG);
        toast.show();
    }
}

activity_login_page.xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.majewski.androidbankapplication.LoginPage" >

    <TextView
        android:id="@+id/BankNameTextView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:paddingTop="5dp"
        android:gravity="center_vertical|center_horizontal"
        android:text="@string/welcome_message"
        android:textSize="25sp" />

    <ImageView
        android:id="@+id/bankIconImageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/BankNameTextView"
        android:layout_centerHorizontal="true"
        android:adjustViewBounds="true"
        android:maxHeight="250dp"
        android:maxWidth="250dp"
        android:scaleType="centerInside"
        android:layout_marginTop="5dp"
        android:src="@drawable/bank_icon" />

    <EditText
        android:id="@+id/loginEditText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/bankIconImageView"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="25dp"
        android:ems="10"
        android:hint="@string/login_text_edit" />

    <EditText
        android:id="@+id/passwordEditText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/loginEditText"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="7dp"
        android:ems="10"
        android:hint="@string/password_text_edit"
        android:inputType="textPassword" />

    <Button
        android:id="@+id/loginButon"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/passwordEditText"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="7dp"
        android:text="@string/login_button" />

</RelativeLayout>

master_user.xml:

<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <TableRow
        android:id="@+id/tableRow1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="@dimen/master_layout_padding" >

        <Button
            android:id="@+id/addUserButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/add_user_button_text" />

        <Button
            android:id="@+id/logOutButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="@string/log_out_button_text" />

    </TableRow>

    <ListView
        android:id="@+id/usersList"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
    </ListView>

</TableLayout>

AndroidManifest:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.majewski.androidbankapplication"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="11"
        android:targetSdkVersion="21" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".LoginPage"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity
            android:name="com.majewski.androidbankapplication.MasterUserActivity"
            android:label="@string/app_name2" />
    </application>

</manifest>

What am I doing wrong?

Answer 1

Toast toast = Toast.makeText(MasterUserActivity.this, "It works :)", Toast.LENGTH_LONG);
        toast.show();

just write this in toast. no other error visible. all fine

Answer 2

Try using LoginPage.this.startActivity() in onClickListener() / LoginButtonListener()

loginButton.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View v) {
              Intent intent = new Intent(LoginPage.this, MasterUserActivity.class);
              LoginPage.this.startActivity(intent);
      }
    });

Answer 3

Try this

extend your MasterUserActivity from ActionBarActivity instead of Activity .

Answer 4

Change your LoginButtonListener class to this :

private class LoginButtonListener implements View.OnClickListener {
    @Override
    public void onClick(View v) {

        Intent intent = new Intent(v.getContext(), MasterUserActivity.class);
        v.getContext().startActivity(intent);

    }
}

By the way, it'll be more easy if you do this....

loginButton.setOnClickListener(new OnClickListener() {
  @Override
  public void onClick(View v) {
          Intent intent = new Intent(v.getContext(), MasterUserActivity.class);
          v.getContext().startActivity(intent);
  }
});