如何使用OnPause方法

Question

How to change button text loaded from EditText while in onPause() method?

For example

@Override
public void onPause(){
    button.setText(text.getText().toString());
    super.onPause()
}

When I press the back button it does not change the button text

Answer 1

Leaving aside the question of why you want to do this in onPause() in the first place...

Normally, the state of your views would be saved in onSaveInstanceState(...) . But according to the docs , there are no guarantees about whether the call to onSaveInstanceState(...) will occur before or after the call to onPause() . If onSaveInstanceState(...) is called before onPause() , then any changes you make in onPause() will be lost.

Answer 2

Please read documentation - it describes Android activity flow with excellent diagrams.
onPause() is already existing method in Your activity, thus You will need to @Override it. Unless You modified back button behavior - here is what happens:

• onPause() is executed when You press back, and button text is replaced (assuming text and button are visible in this scope) - for such short time, You won't be able to notice (unless device is lagging, anyway)
• onStop() is executed next, and Your application exits shortly after

If You want to try and check that text is properly set - You might find it easier to write:

@Override
public void onPause(){
    super.onPause();
    Log.d("Text's text:" + text.getText().toString()
          + "Button:" + button.getText().toString());

}

You will need to import android.util.Log .
Notice also, that it is highly recommended ( here ) that You call super() as first thing when overriding Android default methods.