Answers for "android navigation back button"

android back navigation

@Override
public boolean onOptionsItemSelected(@NonNull MenuItem item) {
  int itemId = item.getItemId();
  if (itemId == android.R.id.home) {
    // force up navigation to have the same behavior as temporal navigation
    onBackPressed();
    return true;
  } else {
    return super.onOptionsItemSelected(item);
  }
}

back button android studio

<meta-data
      android:name="android.support.PARENT_ACTIVITY"
      android:value=".MainActivity" />