Android StartActivity 不会开始新的活动

Question

I have two methods defined inside this class:

RegisterButtonClicked successfully calls an activity, but LoginButtonClicked won't....

The result of running this code is that it prints out "inside LoginButtonClicked2" log message which means the code is running the LoginButtonClicked method but not successfully executing the startActivity inside the method.

public class MainActivity extends AppCompatActivity {


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

    }

    public void RegisterButtonClicked(View view) {
        Log.d("registerButtonClicked", "inside registerButtonClicked");
        Button Register = findViewById(R.id.RegisterButton);
        Register.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                startActivity(new Intent(MainActivity.this, Register.class));
            }
        });
    }
    public void LoginButtonClicked(View view) {
        Log.d("LoginButtonClicked", "inside LoginButtonClicked");
        Button login = findViewById(R.id.LoginButton);
        login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Log.d("LoginButtonClicked", "inside LoginButtonClicked2");
                startActivity(new Intent(MainActivity.this, Login2.class));
            }
        });
    }
}

here is my activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    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"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/RegisterButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentStart="true"
        android:layout_alignParentLeft="true"
        android:layout_marginBottom="191dp"
        android:layout_marginStart="134dp"
        android:layout_marginLeft="134dp"
        android:text="Register"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        tools:layout_editor_absoluteY="266dp"
        android:onClick = "RegisterButtonClicked"/>
    <Button
        android:id="@+id/LoginButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentStart="true"
        android:layout_alignParentLeft="true"
        android:layout_marginBottom="150dp"
        android:layout_marginStart="134dp"
        android:layout_marginLeft="134dp"
        android:text="Log in"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        tools:layout_editor_absoluteY="200dp"
        android:onClick = "LoginButtonClicked"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentStart="true"
        android:layout_alignParentLeft="true"
        android:layout_centerVertical="true"
        android:layout_marginStart="107dp"
        android:layout_marginLeft="107dp"
        android:text="Welcome to Pick Rose!"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</RelativeLayout>

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.pickrose3, PID: 8252
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.pickrose3/com.pickrose3.Login2}: java.lang.IllegalArgumentException: Given String is empty or null
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)
        at android.app.ActivityThread.-wrap12(ActivityThread.java)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:154)
        at android.app.ActivityThread.main(ActivityThread.java:6077)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)
     Caused by: java.lang.IllegalArgumentException: Given String is empty or null
        at com.google.android.gms.common.internal.Preconditions.checkNotEmpty(Unknown Source)
        at com.google.firebase.auth.FirebaseAuth.signInWithEmailAndPassword(com.google.firebase:firebase-auth@@19.0.0:202)
        at com.pickrose3.Login2.onCreate(Login2.java:60)
        at android.app.Activity.performCreate(Activity.java:6662)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2599)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707) 
        at android.app.ActivityThread.-wrap12(ActivityThread.java) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460) 
        at android.os.Handler.dispatchMessage(Handler.java:102) 
        at android.os.Looper.loop(Looper.java:154) 
        at android.app.ActivityThread.main(ActivityThread.java:6077) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756) 

Answer 1

You may change your java code as below (consider it as one of the possible ways to solve this, please:):

public class MainActivity extends AppCompatActivity {

    public void RegisterButtonClicked(View RegisterButtonClicked) {
        startActivity(new Intent(MainActivity.this, Register.class));
    }

    public void LoginButtonClicked(View LoginButtonClicked) {
        startActivity(new Intent(MainActivity.this, Login2.class));
    }

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

}

Answer 2

If your are setting click from xml then dont need to set click listener in code.

 public void RegisterButtonClicked(View view) {
                Log.d("registerButtonClicked", "inside registerButtonClicked");
                        startActivity(new Intent(MainActivity.this, Register.class));
            }

public void LoginButtonClicked(View view) {
                Log.d("LoginButtonClicked", "inside LoginButtonClicked");
                startActivity(new Intent(MainActivity.this, Login2.class));
            }