Android: How switch between two activities by screen orientation

How to fix warning: "Calling ActionMode finish() in onConfigurationChanged() can lead to redraws".

There are two activities: MainActivity and SecondActivity.

• MainActivity should be displayed in the portrait orientation
• SecondActivity should be displayed in the landscape orientation

We need such attributes in Manifest:

<activity
        android:name=".MainActivity"
        android:screenOrientation="fullSensor"
        android:configChanges="orientation|screenSize"
...
<activity
        android:name=".SecondActivity"
        android:screenOrientation="fullSensor"
...

MainActivity starts SecondActivity when the screen is rotated into LANDSCAPE:

import static android.content.res.Configuration.ORIENTATION_PORTRAIT;
...
@Override
public void onConfigurationChanged(@NonNull Configuration newConfig) {
  super.onConfigurationChanged(newConfig);

  if (ORIENTATION_LANDSCAPE == newConfig.orientation) {
    startActivity(new Intent(this, SecondActivity.class));
  }
}

SecondActivity checks on create if current orientation is LANDSCAPE, otherwise it finishes:

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    if (ORIENTATION_PORTRAIT == getResources().getConfiguration().orientation) {
      finish();
      return;
    }

    setContentView(R.layout.second_activity);
    ...
  }

When attribute configChanges="orientation|screenSize" is not present - activity will be recreated on each screen rotation, otherwise - method onConfigurationChanged is called.

Test cases

Test 1

1. Start in portrait orientation:

MainActivity.onCreate()
MainActivity.onStart()
MainActivity.onResume()

2. Rotate into landscape orientation:

MainActivity.onConfigurationChanged()
MainActivity.onPause()
SecondActivity.onCreate()
SecondActivity.onStart()
SecondActivity.onResume()
MainActivity.onStop()

3. Rotate back into portrait orientation:

SecondActivity.onPause()
SecondActivity.onStop()
SecondActivity.onDestroy()
SecondActivity.onCreate()
MainActivity.onConfigurationChanged()
MainActivity.onRestart()
MainActivity.onStart()
MainActivity.onResume()
SecondActivity.onDestroy()

Test 2

1. Start in landscape orientation:

MainActivity.onCreate()
MainActivity.onStart()
MainActivity.onResume()
MainActivity.onPause()
SecondActivity.onCreate()
SecondActivity.onStart()
SecondActivity.onResume()
MainActivity.onStop()

2. Rotate into portrait orientation:

SecondActivity.onPause()
SecondActivity.onStop()
SecondActivity.onDestroy()
SecondActivity.onCreate()
MainActivity.onConfigurationChanged()
MainActivity.onRestart()
MainActivity.onStart()
MainActivity.onResume()
SecondActivity.onDestroy()

3. Rotate back into landscape orientation:

MainActivity.onConfigurationChanged()
MainActivity.onPause()
SecondActivity.onCreate()
SecondActivity.onStart()
SecondActivity.onResume()
MainActivity.onStop()

Test 3

1. Start in portrait orientation.
2. Minimize application:

MainActivity.onPause()
MainActivity.onStop()

3. Rotate into landscape orientation.
4. Restore application:

MainActivity.onConfigurationChanged()
MainActivity.onRestart()
MainActivity.onStart()
MainActivity.onResume()
MainActivity.onPause()
SecondActivity.onCreate()
SecondActivity.onStart()
SecondActivity.onResume()
MainActivity.onStop()

Test 4

1. Start in landscape orientation.
2. Minimize application:

SecondActivity.onPause()
SecondActivity.onStop()

3. Restore application:

SecondActivity.onDestroy()
SecondActivity.onCreate()
MainActivity.onConfigurationChanged()
MainActivity.onRestart()
MainActivity.onStart()
MainActivity.onResume()
SecondActivity.onDestroy()