Must be one of: View.VISIBLE,View.INVISIBLE,View.GONE less... (Ctrl+F1) 
Reports two types of problems:
- Supplying the wrong type of resource identifier. For example,when calling Resources.getString(int id),you should be passing R.string.something,not R.drawable.something.
- Passing the wrong constant to a method which expects one of a specific set of constants. For example,when calling View#setLayoutDirection,the parameter must be android.view.View.LAYOUT_DIRECTION_LTR or android.view.View.LAYOUT_DIRECTION_RTL.

代码编译并运行,没有错误

码

@Override
public void onSaveInstanceState(@NonNull Bundle savedInstanceState) {
    savedInstanceState.putInt("BUTTON_VISIBILITY",mButton.getVisibility());
 
    super.onSaveInstanceState(savedInstanceState);
}
 
public void onRestoreInstanceState(@NonNull Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);
 
    mButton.setVisibility(savedInstanceState.getInt("BUTTON_VISIBILITY"));
    // savedInstanceState.getInt("BUTTON_VISIBILITY") is underlined red
}