Question

I want to find a ToggleButton in a non-activity class ,but i get a nullpointerException .i did like next code:

public class ClassMode{
    public static boolean isClassMode(Context c) {
    ToggleButton t = new ToggleButton(c);
    t = (ToggleButton) t.findViewById(R.id.classmode);
    if (t.isChecked()) {
        return true;
    } else {
        return false;
    }
}

 public static void setNextMode(final Context context){
   if（isClassMode){
        dosomething();
    }
  }
}

did i make anything wrong? i am a new progromer,i suppose this question maybe nothing.but for me is in contrary.
Anybody help me ,please!Looking forward for your reply.
3Q!

Answer 1

findViewById will find a view within the object you call it on. Usually it’s called on an activity, but can also be called on any ViewGroup that has children.

On your case, you call it on a Button object. I doubt this button contains a child with id R.id.classmode.

Try:

c.findViewById(R.id.classmode)

(Note: you should post a LogCat with the actual exception you’re getting, else we’re only guessing)