我正在viewModelScope
使用ViewModel
的挂起函数,如下所示:
视图模型
class DeepFilterViewModel(val repo: DeepFilterRepository) : ViewModel() {
var deepFilterLiveData: LiveData<Result>? = null
fun onImageCompressed(compressedImage: File): LiveData<Result>? {
if (deepFilterLiveData == null) {
viewModelScope.launch {
deepFilterLiveData = repo.applyFilter(compressedImage)
}
}
return deepFilterLiveData
}
}
存储库
class DeepFilterRepository {
suspend fun applyFilter(compressedImage: File): LiveData<Result> {
val mutableLiveData = MutableLiveData<Result>()
mutableLiveData.value = Result.Loading
withContext(Dispatchers.IO) {
mutableLiveData.value = Result.Success("Done")
}
return mutableLiveData
}
}
我正在观察片段中的 LiveData,如下所示:
viewModel.onImageCompressed(compressedImage)?.observe(this, Observer { result ->
when (result) {
is Result.Loading -> {
loader.makeVisible()
}
is Result.Success<*> -> {
// Process result
}
}
})
问题是我没有从 LiveData 中获得任何价值。如果我不使用viewModelScope.launch {}
如下所示,那么一切正常。
class DeepFilterViewModel(val repo: DeepFilterRepository) : ViewModel() {
var deepFilterLiveData: LiveData<Result>? = null
fun onImageCompressed(compressedImage: File): LiveData<Result>? {
if (deepFilterLiveData == null) {
deepFilterLiveData = repo.applyFilter(compressedImage)
}
return deepFilterLiveData
}
}
我不知道我错过了什么。任何帮助将不胜感激。