ExpandableListView沒有以正確的順序出現

Question

我在敲一個Android應用程序，我決定使用可擴展列表視圖。我有我需要的一切，表工作正常，但是當我填充它，團體似乎是在不同的順序比他們應該，這裏有一個例子：

正如你所看到的，子值很好，只有父值以隨機順序出現。下面是完整的代碼，我有：

我的片段代碼：

public class BuildingsFragment extends Fragment { 


public BuildingsFragment() { 
    // Required empty public constructor 
} 


public static BuildingsFragment newInstance(Context context) { 
    BuildingsFragment fragment = new BuildingsFragment(); 

    return fragment; 
} 


@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 


} 


@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
    // Inflate the layout for this fragment 
    View view = inflater.inflate(R.layout.fragment_buildings, container, false); 


    final ExpandableListView expandableListView = (ExpandableListView) view.findViewById(R.id.expandableListViewBuildings); 
    HashMap<String, List<String>> expandableListDetail = ExpandableListDataPump.getData(); 
    List<String> expandableListTitle = new ArrayList<String>(expandableListDetail.keySet()); 
    ExpandableListAdapter expandableListAdapter = new CustomExpandableListAdapter(getContext(), expandableListTitle, expandableListDetail); 
    expandableListView.setAdapter(expandableListAdapter); 


    expandableListView.setOnChildClickListener(new ExpandableListView.OnChildClickListener() { 
     @Override 
     public boolean onChildClick(ExpandableListView parent, View v, int groupPosition, int childPosition, long id) { 


      Fragment fragment = null; 
      Class fragmentClass = BuildingDetailsFragment.class; 



      try { 
       fragment = (Fragment) fragmentClass.newInstance(); 
      } catch (Exception e) { 
       e.printStackTrace(); 
      } 

      FragmentTransaction trans = getFragmentManager().beginTransaction(); 


      Bundle args = new Bundle(); 
      args.putString("BUILDING_NAME", "test"); 
      fragment.setArguments(args); 


      trans.replace(R.id.frameLayoutForFragments, fragment); 


      trans.addToBackStack(null); 


      trans.commit(); 


      return false; 
     } 
    }); 


    return view; 
} 
} 

我的自定義適配器：

public class CustomExpandableListAdapter extends BaseExpandableListAdapter { 

private Context context; 
private List<String> expandableListTitle; 
private HashMap<String, List<String>> expandableListDetail; 

public CustomExpandableListAdapter(Context context, List<String> expandableListTitle, HashMap<String, List<String>> expandableListDetail) { 
    this.context = context; 
    this.expandableListTitle = expandableListTitle; 
    this.expandableListDetail = expandableListDetail; 
} 

@Override 
public Object getChild(int listPosition, int expandedListPosition) { 
    return this.expandableListDetail.get(this.expandableListTitle.get(listPosition)) 
      .get(expandedListPosition); 
} 

@Override 
public long getChildId(int listPosition, int expandedListPosition) { 
    return expandedListPosition; 
} 

@Override 
public View getChildView(int listPosition, final int expandedListPosition, 
         boolean isLastChild, View convertView, ViewGroup parent) { 
    final String expandedListText = (String) getChild(listPosition, expandedListPosition); 
    if (convertView == null) { 
     LayoutInflater layoutInflater = (LayoutInflater) this.context 
       .getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
     convertView = layoutInflater.inflate(R.layout.list_view_buildings_row_layout, null); 
    } 
    TextView expandedListTextView = (TextView) convertView 
      .findViewById(R.id.expandedListItem); 
    expandedListTextView.setText(expandedListText); 
    return convertView; 
} 

@Override 
public int getChildrenCount(int listPosition) { 
    return this.expandableListDetail.get(this.expandableListTitle.get(listPosition)) 
      .size(); 
} 

@Override 
public Object getGroup(int listPosition) { 
    return this.expandableListTitle.get(listPosition); 
} 

@Override 
public int getGroupCount() { 
    return this.expandableListTitle.size(); 
} 

@Override 
public long getGroupId(int listPosition) { 
    return listPosition; 
} 

@Override 
public View getGroupView(int listPosition, boolean isExpanded, 
         View convertView, ViewGroup parent) { 
    String listTitle = (String) getGroup(listPosition); 
    if (convertView == null) { 
     LayoutInflater layoutInflater = (LayoutInflater) this.context. 
       getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
     convertView = layoutInflater.inflate(R.layout.list_view_buildings_group_layout, null); 
    } 
    TextView listTitleTextView = (TextView) convertView 
      .findViewById(R.id.listGroup); 
    listTitleTextView.setTypeface(null, Typeface.BOLD); 
    listTitleTextView.setText(listTitle); 
    return convertView; 
} 

@Override 
public boolean hasStableIds() { 
    return false; 
} 

@Override 
public boolean isChildSelectable(int listPosition, int expandedListPosition) { 
    return true; 
} 
} 

我使用的ExpandableListDataPump：

public class ExpandableListDataPump { 
public static HashMap<String, List<String>> getData() { 

    HashMap<String, List<String>> expandableListDetail = new HashMap<String, List<String>>(); 


    List<String> abuildings = new ArrayList<String>(); 
    abuildings.add("A-1"); 
    abuildings.add("A-2"); 
    abuildings.add("A-3"); 
    abuildings.add("A-5"); 
    abuildings.add("A-7"); 
    expandableListDetail.put("A", abuildings); 

    List<String> bbuildings = new ArrayList<String>(); 
    bbuildings.add("B-1"); 
    bbuildings.add("B-2"); 
    bbuildings.add("B-3"); 
    bbuildings.add("B-5"); 
    bbuildings.add("B-6"); 
    expandableListDetail.put("B", bbuildings); 

    List<String> cbuildings = new ArrayList<String>(); 
    cbuildings.add("C-1"); 
    cbuildings.add("C-3"); 
    cbuildings.add("C-4"); 
    cbuildings.add("C-5"); 
    cbuildings.add("C-6"); 
    expandableListDetail.put("C", cbuildings); 

    List<String> dbuildings = new ArrayList<String>(); 
    dbuildings.add("D-1"); 
    dbuildings.add("D-2"); 
    dbuildings.add("D-3"); 
    dbuildings.add("D-5"); 
    dbuildings.add("D-7"); 
    expandableListDetail.put("D", dbuildings); 

    return expandableListDetail; 
} 
} 

我認爲這是一切與ExpandableListView相關。我真的想離開HashMap，但如果沒有其他方法，我可以將它更改爲TreeMap並使用它的排序功能（作爲最後的手段）？感謝幫助。

P.S.雖然這樣做我ExpandableListView我下面這個教程（我不知道，如果該事項）：Tutorial

Answer 1

根據Java規格爲HashMap，訂單不能保證：

...這個類對地圖的順序不作任何保證;特別是，它不能保證訂單隨時間保持不變...

所以，如果你想保證你的組的順序，你將不得不使用不同的數據結構。

請參閱this answer進行類似的討論，並建議使用LinkedHashMap，它維護插入順序。