1. Cancel viewModel Job when viewModel is cleared

   override fun onCleared() {
        super.onCleared()
        viewModelJob.cancel()
    }

---

2. Adding viewModel into Adpater
3. when does viewModel died
4. databinding + notifydatachanged()
5. paylog : save old data for display in recycleView without, does not require request new data.
6. kotlin static: initialize while at run time but app start

1. why >> what
2. Q&A ask G2

A
1.
2. lifecycle overried
3. ANR
4. lambda
5. coroutine

B
1. dd
2. kotlin not pure oop
3. storage
4. runtime permission
5. difference

C
1. jetpack
2. 記憶體配置
3. GC 回收機制
4. message queue