Question

I have three activities ActivityA, ActivityB, ActivityC.

Suppose in ActivityA, there is some code like…

if(someCondition()){
gotoActivityB();
}
else{
gotoActivityC();
}

Now, If user goes to ActivityB, ActivityA should not be finished.

If he goes to ActivityC, it should be finished.

Adding noHistory in manifest file doesn’t work.

Also, finish()in if condition doesn’t work, As there are many activities after ActivityC in which ActivityA should be in background.

I don’t want to call startActivity(context,ActivityA.class)in those activities onBackPressed() because, it will again execute code of onCreate() in ActivityA.

So, is there a way, where i can remove ActivityA from the stack when user presses back button in ActivityB?

may be something like this:?

ActivityB.this.finish();
ActivityA.finish(); //some code to finish ActivityA

Answer 1

Okay, here is one way you can accomplish your goal. You will need to pass around the Activity context to wherever you need it in order to call finish() on it. I used the Application class to do this. I only used two classes to do it for the sake of time, but it should work just fine for your purposes. Here is how I did it:

This is the first class. It is the Activity that we want to close from another Activity.

public class MainActivity extends Activity implements OnClickListener {
private Button button;
// application instance
private MainApplication mainApplication;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mainApplication = (MainApplication) getApplicationContext();
    // set the Activity's context for later usage.  Doing this determines which
    // Activity can be closed from another Activity.
    mainApplication.setActivityContext(this);

    button = (Button) findViewById(R.id.button1);
    button.setOnClickListener(this);
}

public void onClick(View v) {
    switch (v.getId()) {
    case R.id.button1:
        Intent i = new Intent(this, SecondActivity.class);
        startActivity(i);
        break;
    }       
} 
}

This is the Second Activity. Exiting out of it will also cause finish() to be called on the first class:

public class SecondActivity extends Activity {

private Activity activityContext;
private MainApplication mainApplication;

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

    mainApplication = (MainApplication) getApplicationContext();
    // get the Activity context you stored in the MainApplication class
    // so you can call finish on it.
    activityContext = mainApplication.getActivityContext();
}

@Override
protected void onPause() {
    super.onPause();
    // closes your defined Activity.  If you press the back button you will find
    // that you exit right out of the app as the other Activity gets popped off 
    // the stack.
    activityContext.finish();
}
}

And the Application class:

public class MainApplication extends Application {

private Activity activityContext;

public Activity getActivityContext() {
    return activityContext;
}

public void setActivityContext(Activity activityContext) {
    this.activityContext = activityContext;
}

}

And of course make sure to declare your MainApplication class in the AndroidManifest:

<application
    android:name=".MainApplication"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >

This is a sort of hacky way to do this. There may be better ways. But regardless, you have to pass around the context of the Activity that you want to call finish() on. Then you can close it from anywhere.