在 Android Studio 中使用 Fragment 在工具栏中显示和隐藏菜单图标

Question

I am trying to use this code to show and hide menu icon in toolbar with Fragment in Android Studio:

    @Override
    public void onPrepareOptionsMenu(Menu menu) {
        MenuItem IconBTON = menu.findItem(R.id.myIcon);

    if (statusBlueTooth == true){
        IconBTON.setVisible(true);
    }
    if (statusBlueTooth == false){
        IconBTON.setVisible(false);
    }
}

but the icon is not shown even though the value of the flag statusBlueTooth = true, but just when I touch the toolbar the icon is shown, what do I need to do so that this is shown according to the value of flag statusBlueTooth

Answer 1

Try adding this after in your onCreate of your Fragment:

setHasOptionsMenu(true);

and check IconBTON != null before setting the visibility.