Android：RecyclerView GridLayoutManager-恢复滚动位置无法正常工作

Question

我有3个活动：A-> B-> C

在活动B中，我正在使用RecyclerView的GridlayoutManager进行填充。 我想导航到活动C时保存滚动状态，并从活动C返回活动B时恢复滚动状态。

private RecyclerView mImgList;
private GridLayoutManager mRecyclerGridMan;
private final String KEY_RECYCLER_STATE = "recycler_state";
private Parcelable mListState = null;
private static Bundle mBundleRecyclerViewState;

。

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
}

。

@Override
protected void onPause()
{
    super.onPause();
    mBundleRecyclerViewState = new Bundle();
    mListState = mImgList.getLayoutManager().onSaveInstanceState();
    mBundleRecyclerViewState.putParcelable(KEY_RECYCLER_STATE, mListState);
}

。

@Override
protected void onResume()
{
    super.onResume();
    if (mBundleRecyclerViewState != null) {
        mListState = mBundleRecyclerViewState.getParcelable(KEY_RECYCLER_STATE);
        mImgList.getLayoutManager().onRestoreInstanceState(mListState);
    }
}

但这在我从活动B按返回按钮并转到活动A，然后从活动A导航回活动B时起作用。

Answer 1

在onRestoreInstanceState（）中还原状态

protected void onRestoreInstanceState(Bundle state) {
super.onRestoreInstanceState(state);

// Retrieve list state and list/item positions
if(state != null)
   mListState =   mBundleRecyclerViewState.getParcelable(KEY_RECYCLER_STATE);
}