Android之最简单和靠谱的监听Home键和菜单键（最近任务栏）

1、介绍ACTION_CLOSE_SYSTEM_DIALOGS

    /**
     * Broadcast Action: This is broadcast when a user action should request a
     * temporary system dialog to dismiss.  Some examples of temporary system
     * dialogs are the notification window-shade and the recent tasks dialog.
     */
    public static final String ACTION_CLOSE_SYSTEM_DIALOGS = "android.intent.action.CLOSE_SYSTEM_DIALOGS";    /**