Hộp kiểm trong ExpandableListView

Question

Tôi đang sử dụng ExpandableListView trong đó mỗi nhóm là TextView và mỗi đứa trẻ là CheckBox. Tôi đã cố gắng để thực hiện một cái gì đó tương tự như liên kết này:

http://www.vogella.de/articles/AndroidListView/article.html#listadvanced_interactive

nhưng với một ExpandableListView thay vì ListView. Khi chạy, nó đang đưa ra một số lạ ClassCastException trong khi đặt Tag cho hộp kiểm bằng cách sử dụng setTag(). Đây là mã:

public class ExpandableActivity extends Activity { 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 

    ArrayList<String> groups = new ArrayList<String>(); 
    List<List<OptionItem>> children = new ArrayList<List<OptionItem>>(); 

    for (int i = 0; i < 10; i++) { 
     String groupName = "Group " + i; 
     groups.add(groupName); 
     List<OptionItem> temp = new ArrayList<OptionItem>(); 
     for (int j = 0; j < 5; j++) { 
      temp.add(new OptionItem(groupName, "Child " + j)); 
     } 
     children.add(temp); 
    } 

    children.get(0).get(3).setSelected(true); 
    children.get(5).get(2).setSelected(true); 
    children.get(8).get(1).setSelected(true); 
    children.get(3).get(4).setSelected(true); 

    ExpandableListView elv = (ExpandableListView) findViewById(R.id.expandableListView1); 
    elv.setAdapter(new ExpandableAdapter(groups, children)); 

} 

public static class ViewHolder { 
    protected CheckBox cb; 
} 

public class ExpandableAdapter extends BaseExpandableListAdapter { 

    private List<List<OptionItem>> list; 
    private ArrayList<String> groups; 

    public ExpandableAdapter(ArrayList<String> groups, 
      List<List<OptionItem>> children) { 
     this.groups = groups; 
     this.list = children; 
    } 

    @Override 
    public Object getChild(int groupPosition, int childPosition) { 
     if (list != null && list.size() > groupPosition 
       && list.get(groupPosition) != null) { 
      if (list.get(groupPosition).size() > childPosition) 
       return list.get(groupPosition).get(childPosition); 
     } 

     return null; 
    } 

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

    @Override 
    public View getChildView(final int groupPosition, 
      final int childPosition, boolean isLastChild, View convertView, 
      ViewGroup parent) { 

     View view = null; 
     if (convertView == null) { 
      view = getLayoutInflater().inflate(R.layout.row, null); 
      final ViewHolder childHolder = new ViewHolder(); 
      childHolder.cb = (CheckBox) view.findViewById(R.id.checkBox1);    
      childHolder.cb 
        .setOnCheckedChangeListener(new OnCheckedChangeListener() { 
         @Override 
         public void onCheckedChanged(CompoundButton button, 
           boolean isChecked) { 
          OptionItem item = (OptionItem) childHolder.cb 
            .getTag(); 
          item.setSelected(button.isChecked()); 
         } 
        }); 

      view.setTag(childHolder); 
      childHolder.cb.setTag(list.get(groupPosition).get(childPosition)); 
     } else { 
      view = convertView;   
      ((ViewHolder) view.getTag()).cb.setTag(list.get(groupPosition).get(childPosition)); 
     } 

     ViewHolder holder = (ViewHolder) view.getTag(); 
     holder.cb.setChecked(list.get(groupPosition).get(childPosition) 
       .isSelected()); 
     holder.cb.setText(list.get(groupPosition).get(childPosition) 
       .getChildName()); 

     return view; 
    } 

    @Override 
    public int getChildrenCount(int groupPosition) { 
     if (list != null && list.size() > groupPosition 
       && list.get(groupPosition) != null) 
      return list.get(groupPosition).size(); 

     return 0; 
    } 

    @Override 
    public Object getGroup(int groupPosition) { 
     if (groups != null && groups.size() > groupPosition) 
      return groups.get(groupPosition); 

     return null; 
    } 

    @Override 
    public int getGroupCount() { 
     if (groups != null) 
      return groups.size(); 

     return 0; 
    } 

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

    @Override 
    public View getGroupView(int groupPosition, boolean isExpanded, 
      View convertView, ViewGroup parent) { 
     if (convertView == null) { 
      convertView = getLayoutInflater().inflate(
        android.R.layout.simple_expandable_list_item_1, null); 
     } 

     TextView tv = (TextView) convertView 
       .findViewById(android.R.id.text1); 
     tv.setText(groups.get(groupPosition)); 

     return convertView; 
    } 

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

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

và lớp mô hình dữ liệu:

public class OptionItem { 

private String groupName; 
private String childName; 
private boolean selected; 

public OptionItem(String group, String child) { 

    this.groupName = group; 
    this.childName = child; 
    selected = false; 
} 

public void setGroupName(String name) { 
    this.groupName = name; 
} 

public void setChildName(String name) { 
    this.childName = name; 
} 

public void setSelected(boolean selected) { 
    this.selected = selected; 
} 

public String getGroupName() { 
    return groupName; 
} 

public String getChildName() { 
    return childName; 
} 

public boolean isSelected() { 
    return selected; 
} 

Xin vui lòng giúp. Cảm ơn trước.

EDIT: Nhật ký như sau:

02-15 12:40:03.224: E/AndroidRuntime(423): FATAL EXCEPTION: main 
02-15 12:40:03.224: E/AndroidRuntime(423): java.lang.ClassCastException: com.test.OptionItem 
02-15 12:40:03.224: E/AndroidRuntime(423): at com.test.ExpandableActivity$ExpandableAdapter.getChildView(ExpandableActivity.java:106) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.widget.ExpandableListConnector.getView(ExpandableListConnector.java:450) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.widget.AbsListView.obtainView(AbsListView.java:1315) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.widget.ListView.makeAndAddView(ListView.java:1727) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.widget.ListView.fillDown(ListView.java:652) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.widget.ListView.fillSpecific(ListView.java:1284) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.widget.ListView.layoutChildren(ListView.java:1558) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.widget.AbsListView.onLayout(AbsListView.java:1147) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.view.View.layout(View.java:7035) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1249) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1125) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.widget.LinearLayout.onLayout(LinearLayout.java:1042) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.view.View.layout(View.java:7035) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.widget.FrameLayout.onLayout(FrameLayout.java:333) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.view.View.layout(View.java:7035) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1249) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1125) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.widget.LinearLayout.onLayout(LinearLayout.java:1042) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.view.View.layout(View.java:7035) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.widget.FrameLayout.onLayout(FrameLayout.java:333) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.view.View.layout(View.java:7035) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.view.ViewRoot.performTraversals(ViewRoot.java:1045) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.view.ViewRoot.handleMessage(ViewRoot.java:1727) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.os.Handler.dispatchMessage(Handler.java:99) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.os.Looper.loop(Looper.java:123) 
02-15 12:40:03.224: E/AndroidRuntime(423): at android.app.ActivityThread.main(ActivityThread.java:4627) 
02-15 12:40:03.224: E/AndroidRuntime(423): at java.lang.reflect.Method.invokeNative(Native Method) 
02-15 12:40:03.224: E/AndroidRuntime(423): at java.lang.reflect.Method.invoke(Method.java:521) 
02-15 12:40:03.224: E/AndroidRuntime(423): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 
02-15 12:40:03.224: E/AndroidRuntime(423): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 
02-15 12:40:03.224: E/AndroidRuntime(423): at dalvik.system.NativeStart.main(Native Method) 

EDIT: Tôi đã thử nó một lần nữa, nó vẫn được đưa ra cùng một ngoại lệ. Dưới đây là hàng nhập khẩu Tôi đã thêm:

import java.util.ArrayList; 
import java.util.List; 
import android.app.Activity; 
import android.os.Bundle; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.BaseExpandableListAdapter; 
import android.widget.CheckBox; 
import android.widget.CompoundButton; 
import android.widget.CompoundButton.OnCheckedChangeListener; 
import android.widget.ExpandableListView; 
import android.widget.TextView; 

Answer 1

Nhờ Natali, tôi đã tìm ra được vấn đề. Vấn đề nằm trong tệp sơ đồ bố trí "row.xml". Tôi đang sử dụng:

<?xml version="1.0" encoding="utf-8"?> 
<CheckBox xmlns:android="http://schemas.android.com/apk/res/android" 
    android:id="@+id/checkBox1" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="CheckBox" /> 

làm bố cục. Nhưng khi tôi đổi thành:

<?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" 
    android:orientation="vertical" > 

    <CheckBox 
     android:id="@+id/checkBox1" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="CheckBox" /> 

</LinearLayout> 

Nó hoạt động như một sự quyến rũ. Tôi đoán đây là một lỗi. Nhờ Natali đã giúp tôi trong việc tìm ra điều này.

Answer 2

tôi cố gắng mã của bạn, và không có vấn đề:

xin vui lòng thêm nhập khẩu của bạn, có thể có một số vấn đề.