Android, check if back Button was pressed

Question

i have two views and activities. On the first there is a spinner. On the second, you can create new entries (Stored in database for the spinner in activity 1). If the user is finished and pressed the back button, i have to refresh the spinner on activity 1 (because of the new entries).

Ist there a possibility to check, if the app returns to activity 1, because the back button in activity 2 was pressed?

I know, i can do it with the onResume Method, but this method is called EVERYTIME i return to activity one and not ONLY because of the back button.

I want to refresh the spinner only when the back button was pressed.

Any solution? Can i Check if the back button was pressed in the onResume method?

Answer 1

You can override onBackPressed() in the Second Activity. This will get called when the user presses the back button.

You can pass the information as a boolean hasBackPressed = true in the setResult()

Starting Activity 2 from Activity 1:

Intent i = new Intent(this, SecondActivity.class);
startActivityForResult(i, 1);

Passing info back from Activity 2:

    @Override
    public void onBackPressed() {
        Intent returnIntent = new Intent();
        returnIntent.putExtra("hasBackPressed",true);
        setResult(Activity.RESULT_OK,returnIntent);
        finish();
    }

Receiving data in Activity 1:

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {

    if (requestCode == 1) {
        if(resultCode == Activity.RESULT_OK){
            boolean hasBackPressed = data.getBooleanExtra("hasBackPressed");
        }
        if (resultCode == Activity.RESULT_CANCELED) {
            //Write your code if there's no result
        }
    }
}

Answer 2

You can start Activity 2 for result, using startActivityForResult() . On Activity 2 you can set the result to RESULT_OK when new items have been added. Then, in the onActivityResult() method of Activity 1 you can check the returned result and update your data, if needed.

Answer 3

Override the onBackPressed() method and take the action inside this function.

@Override
public void onBackPressed() {
    // your stuff here

    super.onBackPressed();
}

Answer 4

Use startActivityForResult() to start the second activity, and return some value in the onBackPressed() of the second activity. Catch that in onActivityResult() , and refresh the spinner there.

Look into this .