How to set an onClickListener on an included layout?

Replace findViewById(R.id.includeCallEnd0) with findViewById(R.id.includeCallEnd0).findViewById(R.id.phoneEnd) and it should work

because you want to set the click listener on the ImageButton and not the whole layout

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Use the following function to set the OnClickListener once:

private static void applyListener(View child, OnClickListener listener) {
    if (child == null)
        return;

    if (child instanceof ViewGroup) {
        applyListener((ViewGroup) child, listener);
    }
    else if (child != null) {
        if(child.getId() == R.id.phoneEnd) {
            child.setOnClickListener(listener);
        }
    }
}

private static void applyListener(ViewGroup parent, OnClickListener listener) {
    for (int i = 0; i < parent.getChildCount(); i++) {
        View child = parent.getChildAt(i);
        if (child instanceof ViewGroup) {
            applyListener((ViewGroup) child, listener);
        } else {
            applyListener(child, listener);
        }
    }
}

Use applyListener(rootView, yourOnClickListener);

You could have done

LinearLayout endcall0 = (LinearLayout) findViewById(R.id.includeCallEnd0); 

and then simply

ImageButton imgBtn = (ImageButton) endcall0.findViewById(R.id. phoneEnd); 
imgBtn.setOnClickListener(this);