Casilla de verificación en ExpandableListView

Question

Estoy usando un ExpandableListView en el que cada grupo es un TextView y cada hijo es un CheckBox. Yo estaba tratando de poner en práctica algo similar a este enlace:

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

pero con un ExpandableListView en lugar de ListView. En tiempo de ejecución, está dando un extraño ClassCastException mientras configura el Tag para la casilla usando setTag(). Aquí está el código:

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; 
    } 
} 

y la clase de modelo de datos:

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; 
} 

favor, ayuda. Gracias por adelantado.

EDITAR: El registro es el siguiente:

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: He tratado de nuevo, que todavía está dando la misma excepción. Aquí están las importaciones he añadido:

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

Gracias a Natali, he resuelto el problema. El problema estaba en el archivo de diseño "row.xml". Yo estaba usando:

<?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" /> 

como el diseño. Pero cuando lo cambié a:

<?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> 

Funcionó como un encanto. Supongo que esto es un error. Gracias a Natali por ayudarme a descifrar esto.

Answer 2

que probar su código, y no hay problemas:

favor agregue sus importaciones, tal vez hay algunos problemas.