最好的解决方案是:

// save index and top position
int index = mList.getFirstVisiblePosition();
View v = mList.getChildAt(0);
int top = (v == null) ? 0 : (v.getTop() - mList.getPaddingTop());

// ...

// restore index and position
mList.post(new Runnable() {
    @Override
    public void run() {
      mList.setSelectionFromTop(index, top);
   }
});

你必须在邮件和线程中调用!

我使用的是FirebaseListAdapter，不能让任何解决方案工作。我最后做了这个。我猜有更优雅的方式，但这是一个完整的和有效的解决方案。

在onCreate之前:

private int reset;
private int top;
private int index;

FirebaseListAdapter内部:

@Override
public void onDataChanged() {
     super.onDataChanged();

     // Only do this on first change, when starting
     // activity or coming back to it.
     if(reset == 0) {
          mListView.setSelectionFromTop(index, top);
          reset++;
     }

 }

启动时间：

@Override
protected void onStart() {
    super.onStart();
    if(adapter != null) {
        adapter.startListening();
        index = 0;
        top = 0;
        // Get position from SharedPrefs
        SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(this);
        top = sharedPref.getInt("TOP_POSITION", 0);
        index = sharedPref.getInt("INDEX_POSITION", 0);
        // Set reset to 0 to allow change to last position
        reset = 0;
    }
}

停止：

@Override
protected void onStop() {
    super.onStop();
    if(adapter != null) {
        adapter.stopListening();
        // Set position
        index = mListView.getFirstVisiblePosition();
        View v = mListView.getChildAt(0);
        top = (v == null) ? 0 : (v.getTop() - mListView.getPaddingTop());
        // Save position to SharedPrefs
        SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(this);
        sharedPref.edit().putInt("TOP_POSITION" + "", top).apply();
        sharedPref.edit().putInt("INDEX_POSITION" + "", index).apply();
    }
}

因为我还必须解决这个FirebaseRecyclerAdapter，我在这里发布的解决方案:

在onCreate之前:

private int reset;
private int top;
private int index;

FirebaseRecyclerAdapter内部:

@Override
public void onDataChanged() {
    // Only do this on first change, when starting
    // activity or coming back to it.
    if(reset == 0) {
        linearLayoutManager.scrollToPositionWithOffset(index, top);
        reset++;
    }
}

启动时间：

@Override
protected void onStart() {
    super.onStart();
    if(adapter != null) {
        adapter.startListening();
        index = 0;
        top = 0;
        // Get position from SharedPrefs
        SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(this);
        top = sharedPref.getInt("TOP_POSITION", 0);
        index = sharedPref.getInt("INDEX_POSITION", 0);
        // Set reset to 0 to allow change to last position
        reset = 0;
    }
}

停止：

@Override
protected void onStop() {
    super.onStop();
    if(adapter != null) {
        adapter.stopListening();
        // Set position
        index = linearLayoutManager.findFirstVisibleItemPosition();
        View v = linearLayoutManager.getChildAt(0);
        top = (v == null) ? 0 : (v.getTop() - linearLayoutManager.getPaddingTop());
        // Save position to SharedPrefs
        SharedPreferences sharedPref = PreferenceManager.getDefaultSharedPreferences(this);
        sharedPref.edit().putInt("TOP_POSITION" + "", top).apply();
        sharedPref.edit().putInt("INDEX_POSITION" + "", index).apply();
    }
}

private Parcelable state;
@Override
public void onPause() {
    state = mAlbumListView.onSaveInstanceState();
    super.onPause();
}

@Override
public void onResume() {
    super.onResume();

    if (getAdapter() != null) {
        mAlbumListView.setAdapter(getAdapter());
        if (state != null){
            mAlbumListView.requestFocus();
            mAlbumListView.onRestoreInstanceState(state);
        }
    }
}

这就够了

这里提供的解决方案似乎都不适合我。在我的情况下，我有一个ListView在一个片段，我替换在一个FragmentTransaction，所以一个新的片段实例创建每次片段显示，这意味着ListView状态不能存储为片段的成员。

相反，我最终将状态存储在我的自定义Application类中。下面的代码应该会让你了解它是如何工作的:

public class MyApplication extends Application {
    public static HashMap<String, Parcelable> parcelableCache = new HashMap<>();


    /* ... code omitted for brevity ... */
}

public class MyFragment extends Fragment{
    private ListView mListView = null;
    private MyAdapter mAdapter = null;


    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        mAdapter = new MyAdapter(getActivity(), null, 0);
        mListView = ((ListView) view.findViewById(R.id.myListView));

        Parcelable listViewState = MyApplication.parcelableCache.get("my_listview_state");
        if( listViewState != null )
            mListView.onRestoreInstanceState(listViewState);
    }


    @Override
    public void onPause() {
        MyApplication.parcelableCache.put("my_listview_state", mListView.onSaveInstanceState());
        super.onPause();
    }

    /* ... code omitted for brevity ... */

}

基本思想是将状态存储在片段实例之外。如果您不喜欢在应用程序类中拥有静态字段的想法，我猜您可以通过实现一个片段接口并将状态存储在您的活动中来实现它。

另一种解决方案是将其存储在SharedPreferences中，但这有点复杂，您需要确保在应用程序启动时清除它，除非您希望在应用程序启动时保持状态。

另外，为了避免“当第一项可见时滚动位置不保存”，你可以显示一个0px高度的虚拟第一项。这可以通过重写适配器中的getView()来实现，如下所示:

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    if( position == 0 ) {
        View zeroHeightView = new View(parent.getContext());
        zeroHeightView.setLayoutParams(new ViewGroup.LayoutParams(0, 0));
        return zeroHeightView;
    }
    else
        return super.getView(position, convertView, parent);
}

Parcelable state;

@Override
public void onPause() {    
    // Save ListView state @ onPause
    Log.d(TAG, "saving listview state");
    state = listView.onSaveInstanceState();
    super.onPause();
}
...

@Override
public void onViewCreated(final View view, Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    // Set new items
    listView.setAdapter(adapter);
    ...
    // Restore previous state (including selected item index and scroll position)
    if(state != null) {
        Log.d(TAG, "trying to restore listview state");
        listView.onRestoreInstanceState(state);
    }
}

如果在重新加载前保存状态，并在重新加载后恢复状态，则可以在重新加载后保持滚动状态。在我的情况下，我做了一个异步网络请求，并在它完成后在回调中重新加载列表。这是我恢复状态的地方。代码示例是Kotlin。

val state = myList.layoutManager.onSaveInstanceState()

getNewThings() { newThings: List<Thing> ->

    myList.adapter.things = newThings
    myList.layoutManager.onRestoreInstanceState(state)
}