Question

I have a pretty annoying problem here, as Im still trying to internalize each and every bits of what I am doing,

I currently have a LinearLayout, then upon onCreate of the Activity, I will populate or inflate several other LinearLayout’s with Buttons, my problem is that when I try to access the button, it seems that I’m not getting any close or deeper from the LinearLayout, all I can get is the LinearLayout(Parent) and the other LinearLayout(Children), I believe there is a way, Im just totally confused how to do it.

LinearLayout
 ->LinearLayout(Child1)->Button1, Button2, Button3
 ->LinearLayout(Child2)->Button4, Button5, Button6

How would I be able to access and get the Buttons?

My source;

for (int x=0; x<ll.getChildCount(); x++){
  View v = ll.getChildAt(x);
  Class c = v.getClass();
  if(c == LinearLayout.class){
    for(int y=0; y< ; y++){
      **I know there is something that must be done here, likewise, is this the most
      efficient way of doing things?
    }
  }
 Log.i("test", c.getName());
}

Only the LinearLayout(Parent) exist in the XML, others are inflated run-time.

Answer 1

You should be able to simply cast v to a LinearLayout, then access its children just like you did with its parent. Something like:

for (int x=0; x<ll.getChildCount(); x++){
  View v = ll.getChildAt(x);
  Class c = v.getClass();
  if(c == LinearLayout.class){
    //Cast to LinearLayout since View doesn't expose a way to access children
    LinearLayout innerLayout = (LinearLayout)v;
    for(int y=0; y<innerLayout.getChildCount() ; y++){
      Button b = (Button)innerLayout.getChildAt(y);

      //Do something with b
    }
  }
 Log.i("test", c.getName());
}

Depending on your exact hierarchy you could possibly simplify this by removing the reflection and simply doing a null check (if needed, wrap it in a try/catch and catch a ClassCastException). I’ve typically done something like this in situations where I need to traverse a layout tree that’s dynamically generated:

for (int i = 0; i < outerLayout.getChildCount(); ++i)
{
    try
    {
        LinearLayout innerLayout = (LinearLayout)outerLayout.getChildAt(i);

        if (innerLayout != null)
        {
            for (int j = 0; j < innerLayout.getChildCount(); ++j)
            {
                Button btn = (Button)innerLayout.getChildAt(j);

                //Do something with btn
            }
        }
    }
    catch (ClassCastException cEx)
    {
        Log.w("WARN", "Unexpected child type in outerLayout. " + cEx.getMessage());
    }
}

This is an untested example (could need better exception handling depending on your requirements and layouts) but hopefully it gives you the general idea. If you want to be a little bit more type-agnostic you could also use a cast to ViewGroup instead. That would allow you to potentially use different kinds of layout containers as children, if needed, as they are subclasses of ViewGroup (which is where they inherit getChildAt() and getChildCount() from).