滚动位置在列表视图的顶部

Posted 2023-04-19

【中文标题】滚动位置在列表视图的顶部

【英文标题】：Scroll position to be on top in listview

【发布时间】：2017-08-17 21:09:58

【问题描述】：

layout.xml：

<ListView
    android:id="@+id/lv"
    android:layout_
    android:layout_
    android:stackFromBottom="true"

    android:transcriptMode="alwaysScroll" />

片段代码：

public class MediumFragment extends Fragment 

ListView lv;
private int tabNumber = 1;
private DatabaseReference mDatabaseReference;
ArrayList<MissionClass> missionList;

EasyMediumHardArrayAdapter adapter;

private static String TAG = "MediumFragment";
private int positionNum;
private String idNum;
boolean checkingId = false;
int firstCompletelyVisiblePos;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) 
    // Set the layout that you want to display
    View v = inflater.inflate(R.layout.fragment_medium, container, false);
    lv = (ListView) v.findViewById(R.id.lv);
    missionList = new ArrayList<MissionClass>();
    lv.setSelection(0);
    adapter = new EasyMediumHardArrayAdapter(getActivity(), R.layout.list_item_easy_medium_hard, missionList);
    lv.setAdapter(adapter);

    //initializing database reference
    mDatabaseReference = FirebaseDatabase.getInstance().getReference();

    // Retrieve and display data in listview
    retrieveData();

    // Check number of available mission
    checkUnlockMission();

    // To perform onclick event handler
    lvListener();

    return v;


private void retrieveData() 
    // Retrieve the id 7 - 12 datas from Mission table
    mDatabaseReference.child("Mission").orderByKey().startAt("7").endAt("12").addListenerForSingleValueEvent(new ValueEventListener() 
        @Override
        public void onDataChange(DataSnapshot snapshot) 

            for (DataSnapshot child : snapshot.getChildren()) 
                missionList.add(child.getValue(MissionClass.class));
            
            adapter.notifyDataSetChanged();
        

        @Override
        public void onCancelled(DatabaseError databaseError) 
            Log.e(TAG, databaseError.getMessage());
        
    );

每当我启动应用程序时，stackFromBottom="true" 都会使滚动位置处于底部。我希望 stackFromBottom="true" 加上滚动位置位于顶部（listview position = 0 ）。我可以知道怎么做吗？我试过 lv.smoothscrolltoposition() 但它没有帮助。

【参考方案1】：

在您的ListView 上致电setSelectionAfterHeaderView() 以滚动到顶部。

【讨论】：

评论不用于扩展讨论；这个对话是moved to chat。