Actionbar background is not being changed

Question

I have tried with the following code to change the background of the actionbar. It works with 4.3 but not below 4.3. With the following code, null background is being set i

Answer 1

Finally,I found the solution. It was acheived by showing and hiding the title of action bar after setting background.

getActionBar().setBackgroundDrawable(ContextCompat.getDrawable(this,R.drawable.inbox_header)); 
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setDisplayShowTitleEnabled(false);

Thank you all for your concern.

Answer 2

The only think that you can do is to call invalidateOptionsMenu () after setting background for actionbar..

 public void onStartClicked(View v) {
        int Min = 0;
        int Max = 2;

        //Random number generator between 0 and 2 inclusive
        int pos = Min + (int) (Math.random() * ((Max - Min) + 1));

        if (pos == 0) {
            getActionBar().setBackgroundDrawable(
                    getResources().getDrawable(R.drawable.header));
        } else if (pos == 1) {
            getActionBar().setBackgroundDrawable(
                    getResources().getDrawable(R.drawable.inbox_header));

        } else if (pos == 2) {
            getActionBar().setBackgroundDrawable(
                    getResources().getDrawable(R.drawable.outbox_header));

        }
       invalidateOptionsMenu();
    }