Android：RecyclerView GridLayoutManager-恢復滾動位置無法正常工作

Question

我有3個活動：A-> B-> C

在活動B中，我正在使用RecyclerView的GridlayoutManager進行填充。 我想導航到活動C時保存滾動狀態，並從活動C返回活動B時恢復滾動狀態。

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);
    }
}

但這在我從活動B按返回按鈕並轉到活動A，然后從活動A導航回活動B時起作用。

Answer 1

在onRestoreInstanceState（）中還原狀態

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

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