[android q] 从后台启动 Activity 的限制_android11后台启动activity

https://developer.android.com/guide/components/activities/background-starts

https://developer.android.com/training/notify-user/time-sensitive

从Android Q开始android进一步限制了从后台(组件)启动Activity的行为，前台的不受限制。说白了就是用户不知道，你不能随便就蹦出来一个新的界面。想要启动，必须通过“显示通知”的方式来进行，通知用户借助notification来启动新的Activity。

比如

    Intent fullScreenIntent = new Intent(this, CallActivity.class);
    PendingIntent fullScreenPendingIntent = PendingIntent.getActivity(this, 0,
            fullScreenIntent, PendingIntent.FLAG_UPDATE_CURRENT);
 
    NotificationCompat.Builder notificationBuilder =
            new NotificationCompat.Builder(this, CHANNEL_ID)
        .setSmallIcon(R.drawable.notification_icon)
        .setContentTitle("Inco