2021-08-13 解决协程调用LiveData异常后Live

1.重写Observer以便Catch住监听中处理数据的异常

class MyObserver<T>(
  private val error: ((e: Throwable) -> Unit)? = null,
  private val changed: (t: T) -> Unit,
) : Observer<T> {
  override fun onChanged(t: T) {
    try {
      changed.invoke(t)
    } catch (e: Throwable) {
      error?.invoke(e)
    }
  }
}

2.在协程中调用，这里为了方便，直接使用了https://github.com/liujingxing/rxlife

  val liveData = MutableLiveData<Boolean>()
  private fun setLiveDataValue(suc: Boolean) {
    rxLifeScope.launch({
      Log.e("TAG", "赋值=$suc")
      liveData.value = suc
    }, { e ->
      Log.e("TAG", "异常1:${e.message}")
    })
  }

3.调用赋值

btn1.setOnClickListener { setLiveDataValue(false) }
btn2.setOnClickListener { setLiveDataValue(true) }

4.使用MyObserver监听赋值，在btn1点击后，点击btn2依然能收到监听

    liveData.observe(this, MyObserver({ e ->
      Log.e("TAG", "异常2:${e.message}")
    }, { suc ->
      Log.e("TAG", "接收赋值=$suc")
      if (!suc) {
        throw  Throwable("fail")
      } else {
        Toast.makeText(btn1.context, "Success=$suc", Toast.LENGTH_SHORT).show()
      }
    }))

image.png

5.使用默认监听赋值，在btn1点击后，点击btn2无法收到监听

  liveData.observe(this) { suc ->
      Log.e("TAG", "接收赋值=$suc")
      if (!suc) {
        throw  Throwable("fail")
      } else {
        Toast.makeText(mainTv2.context, "Success=$suc", Toast.LENGTH_SHORT).show()
      }
    }

image.png