RecyclerView存储/恢复活动之间的状态

我将我的ListView迁移到RecyclerViews。 通过列表视图，我使用了这里描述的常用技术来存储和恢复活动之间的滚动位置。

如何做与RecyclerViews相同？ RecyclerView.onSaveInstanceState()似乎具有protected访问权限，因此不能直接使用。

Answer 1

好的，回答我自己的问题。 据我了解，因为他们已经分离了布局代码和视图回收代码（因此名称），负责布局状态（和恢复）的组件现在是您的回收站视图中使用的LayoutManager器。

因此，要存储状态您使用相同的模式，但在布局pipe理器，而不是回收站：

 protected void onSaveInstanceState(Bundle state) { super.onSaveInstanceState(state); // Save list state mListState = mLayoutManager.onSaveInstanceState(); state.putParcelable(LIST_STATE_KEY, mListState); } 

在onRestoreInstanceState()恢复状态：

 protected void onRestoreInstanceState(Bundle state) { super.onRestoreInstanceState(state); // Retrieve list state and list/item positions if(state != null) mListState = state.getParcelable(LIST_STATE_KEY); } 

然后更新LayoutManager（我在onResume() ）：

 @Override protected void onResume() { super.onResume(); if (mListState != null) { mLayoutManager.onRestoreInstanceState(mListState); } } 

Answer 2

我find了一个更好的解决scheme – 这个解决scheme有以下好处：

1. RecyclerView状态保存并在手机旋转时恢复
2. RecyclerView状态被保存并且在恢复到 RecyclerView的活动时被恢复（在另一个活动显示的时候没有被销毁 – 这意味着onRestoreInstanceState()不被调用!!）

码

 public class ActivityItemList extends AppCompatActivity { private final String KEY_RECYCLER_STATE = "recycler_state"; private RecyclerView mRecyclerView; private static Bundle mBundleRecyclerViewState; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_list);//set to whatever layout name you have mRecyclerView = (RecyclerView) findViewById(R.id.recycler_view);//set to whatever view id you use // don't forget to set your adapter } @Override protected void onPause() { super.onPause(); // save RecyclerView state mBundleRecyclerViewState = new Bundle(); Parcelable listState = mRecyclerView.getLayoutManager().onSaveInstanceState(); mBundleRecyclerViewState.putParcelable(KEY_RECYCLER_STATE, listState); } @Override protected void onResume() { super.onResume(); // restore RecyclerView state if (mBundleRecyclerViewState != null) { Parcelable listState = mBundleRecyclerViewState.getParcelable(KEY_RECYCLER_STATE); mRecyclerView.getLayoutManager().onRestoreInstanceState(listState); } } } 

Answer 3

在onPause()和onResume()使用这个代码来保存和恢复滚动位置 –

 private Parcelable recyclerViewState; recyclerViewState = mrecyclerView.getLayoutManager().onSaveInstanceState();//save mrecyclerView.getLayoutManager().onRestoreInstanceState(recyclerViewState);//restore 

Answer 4

这是我的解决scheme，它恢复了物品和RecyclerView的位置

1）在onSaveInstanceState方法中保存回收视图状态

 @Override protected void onSaveInstanceState(Bundle outState) { Parcelable listState = myRecyclerView.getLayoutManager().onSaveInstanceState(); // putting recyclerview position outState.putParcelable(SAVED_RECYCLER_VIEW_STATUS_ID, listState); // putting recyclerview items outState.putParcelableArrayList(SAVED_RECYCLER_VIEW_DATASET_ID,mDataset); super.onSaveInstanceState(outState); } 

2）在onCreate方法中检查savedInstanceState Bundle

 @Override protected void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); if (mSavedInstanceState==null){ getRemoteData(); // No saved data, get data from remote }else{ restorePreviousState(); // Restore data found in the Bundle } } 

3）如果屏幕已经旋转，则恢复回收商视图数据

 public void restorePreviousState(){ // getting recyclerview position mListState = mSavedInstanceState.getParcelable(SAVED_RECYCLER_VIEW_STATUS_ID); // getting recyclerview items mDataset = mSavedInstanceState.getParcelableArrayList(SAVED_RECYCLER_VIEW_DATASET_ID); // Restoring adapter items mAdapter.setItems(mDataset); // Restoring recycler view position mRvMedia.getLayoutManager().onRestoreInstanceState(mListState); }