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美好的一天，我在ExpandableListView的上下文菜单中遇到麻烦。我遵循Android网站的例子，但在这一行上得到一个ClassCastException。ContextMenu上的ClassCastException ExpandableListView的项目
String title = ((TextView)info.targetView).getText().toString();
这是我的代码，只是发布主要部分。
private class expandableList extends SimpleExpandableListAdapter {
public expandableList(Context context,
List<? extends Map<String, ?>> groupData, int groupLayout, String[] groupFrom, int[] groupTo,List<? extends List<? extends Map<String, ?>>> childData,int childLayout, String[] childFrom, int[] childTo) {
super(context, groupData, groupLayout, groupFrom, groupTo, childData, childLayout, childFrom, childTo);
// TODO Auto-generated constructor stub
}
@Override
public View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent){
final View v = super.getChildView(groupPosition, childPosition, isLastChild, convertView, parent);
((TextView)v.findViewById(R.id.search_device_id)).setText((String)((Map<String,Object>)getChild(groupPosition, childPosition)).get(Name));
return v;
}
@Override
public View newChildView(boolean isLastChild, ViewGroup parent){
return LayoutInflater.from(getApplicationContext()).inflate(R.layout.search_devices, null);
}
}
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo{
super.onCreateContextMenu(menu, v, menuInfo);
menu.setHeaderTitle("Devices");
menu.add(0, MENU_HOME, 0, "Home");
}
public boolean onContextItemSelected(MenuItem menuItem){
ExpandableListContextMenuInfo info = (ExpandableListContextMenuInfo) menuItem.getMenuInfo();
int groupPosition = 0;
int childPosition = 0;
int type = ExpandableListView.getPackedPositionChild(info.packedPosition);
if(type == ExpandableListView.PACKED_POSITION_TYPE_CHILD){
groupPosition = ExpandableListView.getPackedPositionGroup(info.packedPosition);
childPosition = ExpandableListView.getPackedPositionChild(info.packedPosition);
}
switch(menuItem.getItemId()){
case MENU_HOME:
/*classcast exception here on this line*/
String title = ((TextView)info.targetView).getText().toString();
Toast.makeText(this, title, Toast.LENGTH_SHORT).show();
}
return false;
}
}
这里是我的Search_devices.xml：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal">
<ImageView
android:id="@+id/device_image_id"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/icon">
</ImageView>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/search_device_id"
android:gravity="center_horizontal|bottom"
android:textColor="#ffffff"
android:padding="2dp">
</TextView>
</LinearLayout>
，这是logcat的消息：
09-15 17:17:41.733: ERROR/AndroidRuntime(4729): java.lang.ClassCastException: android.widget.LinearLayout
09-15 17:17:41.733: ERROR/AndroidRuntime(4729):at com.AappDevs.BlueShare.RecentDevices.onContextItemSelected(RecentDevices.java:200)
09-15 17:17:41.733: ERROR/AndroidRuntime(4729):at android.app.Activity.onMenuItemSelected(Activity.java:2254)
09-15 17:17:41.733: ERROR/AndroidRuntime(4729):at com.android.internal.policy.impl.PhoneWindow$ContextMenuCallback.onMenuItemSelected(PhoneWindow.java:2903)
09-15 17:17:41.733: ERROR/AndroidRuntime(4729):at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:160)
09-15 17:17:41.733: ERROR/AndroidRuntime(4729):at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:885)
09-15 17:17:41.733: ERROR/AndroidRuntime(4729):at com.android.internal.view.menu.MenuDialogHelper.onClick(MenuDialogHelper.java:137)
09-15 17:17:41.733: ERROR/AndroidRuntime(4729):at com.android.internal.app.AlertController$AlertParams$3.onItemClick(AlertController.java:880)
09-15 17:17:41.733: ERROR/AndroidRuntime(4729):at android.widget.AdapterView.performItemClick(AdapterView.java:284)
09-15 17:17:41.733: ERROR/AndroidRuntime(4729):at android.widget.ListView.performItemClick(ListView.java:3604)
请任何帮助，将不胜感激感谢。
编辑：这是RecentDevice类的其余部分，这里的一切都包含在它包括expandableList类：
公共类RecentDevices扩展ExpandableListActivity { 公共静态字符串变量=“HOMESHARE”;
TextView device_name;
ImageView device_image;
View v;
//variables for expandablelistview
final String Name = "name";
final String Image = "image";
//static variables for context menu order
static final int MENU_HOME = Menu.FIRST;
final ArrayList<HashMap<String,String>> headerData = new ArrayList<HashMap<String,String>>();
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.recent_devices);
LayoutInflater layoutinflater = (LayoutInflater)this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
//ArrayList of header and child view in expandablelistview
//final ArrayList<HashMap<String,String>> headerData = new ArrayList<HashMap<String,String>>();
final ArrayList<ArrayList<HashMap<String,Object>>> childData = new ArrayList<ArrayList<HashMap<String,Object>>>();
//Add data to header
final HashMap<String,String> group1 = new HashMap<String,String>();
group1.put(Name,"Home devices");
headerData.add(group1);
final HashMap<String, String> group2 = new HashMap<String, String>();
group2.put(Name, "Work devices");
headerData.add(group2);
//initialise Hashmap for data in child view
final ArrayList<HashMap<String, Object>> group1data = new ArrayList<HashMap<String,Object>>();
childData.add(group1data);
final ArrayList<HashMap<String, Object>> group2data = new ArrayList<HashMap<String,Object>>();
childData.add(group2data)
final HashMap<String, Object> map = new HashMap<String,Object>();
map.put(Name, "Computers");
group1data.add(map);
}
}
//childData.add(group1data);
//add data into adapter and show
Log.d(TAG, "set expandlistview");
expandableList expand_list = new expandableList(this, headerData,
android.R.layout.simple_expandable_list_item_1, new String[]{Name}, new int[]{android.R.id.text1},
(List<? extends List<? extends Map<String, ?>>>) childData, 0, null, new int[]{});
Log.d(TAG, "set expandlistview completed");
setListAdapter(expand_list);
registerForContextMenu(getExpandableListView());
}
哦..非常感谢。缓解了轻微的头痛。很棒！ :) – Rexx