[英]ViewModel Observer first argument is require Lifecycleowner
我正在嘗試使用Android ViewModel和LiveData,但是在創建觀察值時出現錯誤。 第一個參數給我一個錯誤:第一個參數類型錯誤,並且是Lifecycleowner。 如果我嘗試構建它:不兼容的類型:FragStat無法轉換為LifecycleOwner我正在使用構建工具27.0.1,並且對於支持庫也是如此。
這是我的片段:
import android.arch.lifecycle.Observer;
import android.arch.lifecycle.ViewModelProviders;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import com.example.konem.pubgstat.Adapters.StatAdapter;
import com.example.konem.pubgstat.LocalStatViewModel;
import com.example.konem.pubgstat.Models.LocalStat;
import com.example.konem.pubgstat.R;
import com.example.konem.pubgstat.Utils.LocalData.AppDatabase;
import com.example.konem.pubgstat.Utils.UserManager;
import org.androidannotations.annotations.AfterViews;
import org.androidannotations.annotations.EFragment;
import org.androidannotations.annotations.ViewById;
import java.util.List;
import static android.content.ContentValues.TAG;
@EFragment(R.layout.fragment_frag_stat)
public class FragStat extends Fragment {
private List<LocalStat> localStats;
private StatAdapter statAdapter;
private AppDatabase appDatabase;
private UserManager userManager;
@ViewById
RecyclerView rvStats;
@AfterViews
void init() {
appDatabase = AppDatabase.getAppDatabase(getActivity());
userManager = new UserManager(getActivity());
LocalStatViewModel mViewModel =
ViewModelProviders.of(this).get(LocalStatViewModel.class);
statAdapter = new StatAdapter(localStats);
rvStats.setLayoutManager(new LinearLayoutManager(getActivity()));
rvStats.setAdapter(statAdapter);
subscribetostats(mViewModel);
}
private void subscribetostats(LocalStatViewModel localStatViewModel) {
localStatViewModel.getList().observe(this, new Observer<List<LocalStat>>() {
@Override
public void onChanged(@Nullable List<LocalStat> localStats) {
}
});
}
}
設置從DOA界面獲取記錄的返回類型為
LiveData<List<LocatStat>> getAllStats();
然后分段獲取實時數據,
LiveData<List<LocalStat> localStats;
最后在片段中設置Livedata觀察器
localStats.getList().observe(this, new Observer<List<LocalStat>>() {
@Override
public void onChanged(@Nullable List<LocalStat> localStats) {
// Update UI
}
});
因此,經過幾天的嘗試,我發現了問題。 您必須在每一個片段或活動中都包含這幾行,我認為是由appcombat實現的,但不是...
private LifecycleRegistry mLifecycleRegistry;
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mLifecycleRegistry = new LifecycleRegistry(this);
mLifecycleRegistry.markState(Lifecycle.State.CREATED);
}
@Override
public void onStart() {
super.onStart();
mLifecycleRegistry.markState(Lifecycle.State.STARTED);
}
@NonNull
@Override
public Lifecycle getLifecycle() {
return mLifecycleRegistry;
}
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