NetworkBoundResource.java 文件源码

@MainThread
public NetworkBoundResource(AppExecutors appExecutors) {
  this.appExecutors = appExecutors;
  result.setValue(Resource.loading(null));
  LiveData<ResultType> dbSource = loadFromDb();
  result.addSource(dbSource, data -> {
    result.removeSource(dbSource);
    if (shouldFetch(data)) {
      fetchFromNetwork(dbSource);
    } else {
      result.addSource(dbSource, newData -> setValue(Resource.success(newData)));
    }
  });
}