As we know, a colored background of action bar permitted in sdk level 11. But there are some applications with colored action bar that have min sdk lower than 11. For example Whatsapp has green action bar but has min sdk:7 WhatsApp FAQ, or the Telegram application has min sdk:8 Telegram FAQ, but has blue action bar.
How these applications work? And how I can do this?
Toolbar (new name for the ActionBar introduced in Lollipop) is just a normal View.
you just set it's background like any other view.
// java toolbar.setBackgroundColor(int color); // or toolbar.setBackgroundResource(int resId); // or XML android:background="@drawable/toolbarBackground"