Android LayoutManager.onSaveInstanceState（）不工作

我正试图用

GridLayoutManager

保存我的

RecyclerView的状态，但在调用活动的
onSaveInstanceState（）
时，以及在布局管理器上尝试调用总是返回的
onSaveInstanceState（）
时。我尝试使用方法“
findFirstVisibleItemPosition
”，但它总是返回-1

RecyclerView有适配器，适配器有一些元素，我可以滚动它们！我不知道为什么我不能获得完全初始化和工作组件的项目位置！请帮忙

这是我的代码：

@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);

    outState.putParcelable(BUNDLE_MOVIES_RECYCLER_VIEW_STATE, mMoviesRecyclerView.getLayoutManager().onSaveInstanceState());

    outState.putInt(BUNDLE_SEGMENT_POSITION, mSelectedFilterPosition);
    outState.putSerializable(BUNDLE_NOW_PLAYING_MOVIE, mNowPlayingMovie);
    outState.putSerializable(BUNDLE_SEGMENTED_MOVIES, mSegmentMovies);
}

问题解决了！要保存布局管理器的状态，需要在活动的onPause方法中调用方法LayoutManager.onSaveInstanceState（）。因为在活动LayoutManager的onSaveInstanceState中，已将其从视图中清除，或者仅删除布局配置。
代码示例：

public class MainActivity extends AppCompatActivity {

 RecyclerView recyclerView;
 private Parcelable mLayoutManagerState;
 private static final String LAYOUT_MANAGER_STATE = "LAYOUT_MANAGER_STATE";

 @Override
 protected void onPause() {
    super.onPause();

    mLayoutManagerState = recyclerView.getLayoutManager().onSaveInstanceState();
 }

 @Override
 public void onCreate(Bundle savedInstanceState, PersistableBundle persistentState) {
    super.onCreate(savedInstanceState, persistentState);
    recyclerView = (RecyclerView) findViewById(R.id.recyclerview);

    if (savedInstanceState != null) {
        mLayoutManagerState = savedInstanceState.getParcelable(LAYOUT_MANAGER_STATE);
        recyclerView.getLayoutManager().onRestoreInstanceState(mLayoutManagerState);
    }
 } 

 @Override
 public void onSaveInstanceState(Bundle outState, PersistableBundle outPersistentState) {
    super.onSaveInstanceState(outState, outPersistentState);

    outState.putParcelable(LAYOUT_MANAGER_STATE, mLayoutManagerState);
 }
}

问题解决了！要保存布局管理器的状态，需要在活动的onPause方法中调用方法LayoutManager.onSaveInstanceState（）。因为在活动LayoutManager的onSaveInstanceState中，已将其从视图中清除，或者仅删除布局配置。
代码示例：

public class MainActivity extends AppCompatActivity {

 RecyclerView recyclerView;
 private Parcelable mLayoutManagerState;
 private static final String LAYOUT_MANAGER_STATE = "LAYOUT_MANAGER_STATE";

 @Override
 protected void onPause() {
    super.onPause();

    mLayoutManagerState = recyclerView.getLayoutManager().onSaveInstanceState();
 }

 @Override
 public void onCreate(Bundle savedInstanceState, PersistableBundle persistentState) {
    super.onCreate(savedInstanceState, persistentState);
    recyclerView = (RecyclerView) findViewById(R.id.recyclerview);

    if (savedInstanceState != null) {
        mLayoutManagerState = savedInstanceState.getParcelable(LAYOUT_MANAGER_STATE);
        recyclerView.getLayoutManager().onRestoreInstanceState(mLayoutManagerState);
    }
 } 

 @Override
 public void onSaveInstanceState(Bundle outState, PersistableBundle outPersistentState) {
    super.onSaveInstanceState(outState, outPersistentState);

    outState.putParcelable(LAYOUT_MANAGER_STATE, mLayoutManagerState);
 }
}

这适用于
片段
？这适用于
片段
？