Activity of singleTask startup mode

On Android 9.0 machine test, if the startup mode Activity B is singleTask, B already exists in the task stack, A start B,

1. startActivity method, Method B calls for time onNewIntent-> onRestart-> onStart-> onResume

2. Use startActivityForResult method, then the startup mode B would degenerate into standard mode, which is the method B calls for onCreate-> onStart-> onResume