How to Solve Android Exception Activity already has an action bar supplied by the window decor
Every Android Activity has a Toolbar or Action-Bar supplied by default by the parent theme "Theme.AppCompat.Light.DarkActionBar". You can find it inside the "styles.xml" file. This theme or style is applied for every Android project created using the available templates. Let us solve this Android exception problem "java.lang.IllegalStateException: This Activity already has an action bar supplied by the window decor.
