似乎無法找出ExpandableListAdapter

Question

我想寫一個簡單的例子，通過網絡拉動外部數據，並通過ExpandableListAdapter填充ExpandableListView。我已經嘗試了幾個例子，並且幾乎失去了。我熟悉ArrayAdapter課程，但看起來ExpandableListAdapter是不同的。這是我當前的應用程序代碼，該代碼顯示什麼：

MyExpandableListAdapter：

public class MyExpandableListAdapter extends BaseExpandableListAdapter { 

    public static class GroupHolder { 
     TextView title; 
    } 

    public static class ChildHolder { 
     TextView title; 
     ImageView icon; 
    } 


    // groups.getChildren() returns the children 
    private List<Group> groups; 

    private Context context; 

    private LayoutInflater inflater; 

    public MyExpandableListAdapter(Context context, List<Group> groups) { 
     this.context = context; 
     this.groups = groups; 
     this.inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
    } 

    public boolean hasStableIds() { 
     return true; 
    } 

    public Object getGroup(int groupPosition) { 
     return groups.get(groupPosition); 
    } 

    public int getGroupCount() { 
     return groups.size(); 
    } 

    public long getGroupId(int groupPosition) { 
     return groupPosition; 
    } 

    public View getGroupView(int groupPosition, boolean isExpanded, 
      View convertView, ViewGroup parent) { 
     GroupHolder holder; 

     if (convertView != null) { 
      holder = (GroupHolder)convertView.getTag(); 
     } else { 
      convertView = inflater.inflate(R.layout.group_item, parent, false); 

      holder = new GroupHolder(); 
      holder.title = (TextView) convertView.findViewById(R.id.group_item_title); 

      convertView.setTag(holder); 
     } 

     holder.title.setText(this.groups.get(groupPosition).getName()); 

     return convertView; 
    } 

    public boolean isChildSelectable(int groupPosition, int childPosition) { 
     return true; 
    } 

    public Object getChild(int groupPosition, int childPosition) { 
     return groups.get(groupPosition).getChildren().get(childPosition); 
    } 

    public long getChildId(int groupPosition, int childPosition) { 
     return childPosition; 
    } 

    public int getChildrenCount(int groupPosition) { 
     return groups.get(groupPosition).getChildren().size(); 
    } 

    public View getChildView(int groupPosition, int childPosition, 
      boolean isLastChild, View convertView, ViewGroup parent) { 
     ChildHolder holder; 

     if (convertView != null) { 
      holder = (ChildHolder) convertView.getTag(); 
     } else { 
      convertView = inflater.inflate(R.layout.child_item, parent, false); 

      holder = new ChildHolder(); 
      holder.title = (TextView) convertView.findViewById(R.id.child_item_title); 
      holder.icon = (ImageView) convertView.findViewById(R.id.child_item_icon); 

      convertView.setTag(holder); 
     } 

     holder.title.setText(groups.get(groupPosition).getChildren().get(childPosition).getName()); 
//  TODO add in image loading. 

     return convertView; 
    } 
} 

MyExpandableListActivity：

public class MyExpandableListActivity extends ExpandableListActivity { 

    private List<Group> groups; 

    private ExpandableListAdapter adapter; 

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

     setContentView(R.layout.group_list); 

     this.groups = new ArrayList<Group>(); 
     Group group = new Group("$1", "Colors"); 
     Child child = new Child("$2", "Red"); 
     groups.getChildren().add(child); 

     this.adapter = new MyExpandableListAdapter(this, groups); 

     setListAdapter(this.adapter); 
    } 
} 

R.layout.group_list：

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
     android:layout_width="fill_parent" 
     android:layout_height="fill_parent"> 

    <ExpandableListView android:id="@+id/android:list" 
      android:layout_width="fill_parent" 
      android:layout_height="fill_parent"/> 

    <TextView android:id="@+id/android:empty" 
      android:text="EMPTY! DOOM!" 
      android:layout_width="fill_parent" 
      android:layout_height="fill_parent"/> 
</LinearLayout> 

R.layout.group_item：

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent"> 

    <TextView android:id="@+id/group_item_title"/> 
</LinearLayout> 

R.layout.child_item：

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:orientation="horizontal"> 

    <ImageView android:id="@+id/child_item_icon" 
      android:layout_width="48px" android:layout_height="48px"/> 

    <TextView android:id="@+id/child_item_title"/> 
</LinearLayout> 

我，當然，我看到「空的！ DOOM！「而不是我在我的活動中添加的列表項目。我在做什麼錯了？

此外，SimpleExpandableListAdapter似乎應該使事情變得簡單，但我完全無法弄清楚它是如何工作的或如何使用它。任何人都可以幫我弄明白這一點嗎？

Answer 1

在這裏回答：How to write custom ExpandableListAdapter

Answer 2

本週我有兩個項目試圖使用「fill_parent」在同一時間和在同一空間。這可能是你的名單被推到我看你在group_list佈局中有一個類似的設置，希望對隱形列表有幫助

Answer 3

如何將LinearLayout更改爲在你的group_list.xml中有一個垂直方向？

它與ExpandableListActivity文檔中給出的佈局不完全匹配。

您還可以在像getView（）方法這樣的地方設置斷點並查看它是否被調用。