ContextMenu 无法使用自定义适配器从 ListView 中删除行
ContextMenu Fails To Remove Row From ListView With Custom Adapter
问题是：我的 ContextMenu 无法使用自定义适配器从 ListView 中删除行，并且
应用程序崩溃并出现错误：UnsupportedOperationException，请参阅 Logcat 输出。
我进行了 Google 搜索并搜索了 Whosebug。 None 我找到的信息解决了这个问题。
我的问题是：我的代码有什么问题？
请提供正确的代码来解决这个问题。
Java代码：
public class TestActivity extends ListActivity {
private String itemNameArray[];
private String dateArray[];
private ListView listview;
CustomListViewAdapter customListViewAdapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test);
registerForContextMenu(getListView());
root = Environment.getExternalStorageDirectory() + File.separator + "/ListTestFiles";
getDir(root);
listview = getListView();
name=itemNameArray;
lastmod=dateArray;
customListViewAdapter = new CustomListViewAdapter(this, name, lastmod);
listview.setAdapter(customListViewAdapter);
} // End of onCreate code.
class CustomListViewAdapter extends ArrayAdapter<String> {
Context context;
String[] nameArray;
String[] modifiedArray;
CustomListViewAdapter(Context c, String[] name, String[] lastmod)
{
super(c, R.layout.layout_item_view, R.id.rowtext, name);
this.context = c;
this.nameArray = name;
this.modifiedArray = lastmod;
}
public View getView(int position, View convertView, ViewGroup parent)
{
LayoutInflater inflater=(LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View row = inflater.inflate(R.layout.layout_item_view, parent, false);
TextView myName;
TextView myLastMod;
myName=(TextView) row.findViewById(R.id.rowtext);
myName.setText(nameArray[position]);
myLastMod=(TextView) row.findViewById(R.id.textView6);
myLastMod.setText(modifiedArray[position]);
return row;
}
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.context_menu, menu);
}
@Override
public boolean onContextItemSelected(MenuItem itemMenu) {
final AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo)itemMenu.getMenuInfo();
switch (itemMenu.getItemId()) {
case R.id.context_menu_rename:
Toast.makeText(this, "Rename", Toast.LENGTH_SHORT).show();
return true;
case R.id.context_menu_delete:
// NOTE TESTING the line of code below caused a runtime error: java.lang.UnsupportedOperationException
customListViewAdapter.remove(customListViewAdapter.getItem(info.position));
customListViewAdapter.notifyDataSetChanged();
Toast.makeText(getApplicationContext(), "position = " + info.position, Toast.LENGTH_SHORT).show();
Toast.makeText(this, "Delete", Toast.LENGTH_SHORT).show();
return true;
return super.onContextItemSelected(itemMenu);
}
}
}
Logcat 输出：
11-13 10:45:21.229 21432-21432/com.testing.listapp D/AndroidRuntime﹕ Shutting down VM
--------- beginning of crash
11-13 10:45:21.246 21432-21432/com.testing.listapp E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.testing.listapp, PID: 21432
java.lang.UnsupportedOperationException
at java.util.AbstractList.remove(AbstractList.java:638)
at java.util.AbstractList$SimpleListIterator.remove(AbstractList.java:75)
at java.util.AbstractCollection.remove(AbstractCollection.java:229)
at android.widget.ArrayAdapter.remove(ArrayAdapter.java:244)
at com.testing.listapp.TestActivity.onContextItemSelected(TestActivity.java:5468)
at android.app.Activity.onMenuItemSelected(Activity.java:2905)
at com.android.internal.policy.impl.PhoneWindow$DialogMenuCallback.onMenuItemSelected(PhoneWindow.java:4701)
at com.android.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:761)
at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:152)
at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:904)
at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:894)
at com.android.internal.view.menu.MenuDialogHelper.onClick(MenuDialogHelper.java:167)
at com.android.internal.app.AlertController$AlertParams.onItemClick(AlertController.java:1082)
at android.widget.AdapterView.performItemClick(AdapterView.java:305)
at android.widget.AbsListView.performItemClick(AbsListView.java:1146)
at android.widget.AbsListView$PerformClick.run(AbsListView.java:3053)
at android.widget.AbsListView.run(AbsListView.java:3860)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
只需从 nameArray 和 modifiedArray 中删除特定位置的项目，然后通知 adapter数据集更改。
我明白了。一个大错误是在需要动态大小数组的地方使用固定大小数组。
改变你的
String nameArray[];
String modifiedArray[];
至
ArrayList<String> nameArray;
ArrayList<String> modifiedArray;
我修改了你的作品：
public class TestActivity extends ListActivity {
private ArrayList<String> itemNameArray;
private ArrayList<String> dateArray;
private ListView listview;
CustomListViewAdapter customListViewAdapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test);
registerForContextMenu(getListView());
String root = Environment.getExternalStorageDirectory() + File.separator + "/ListTestFiles";
getDir(root);
listview = getListView();
CustomListViewAdapter = new CustomListViewAdapter(this, itemNameArray, dateArray);
listview.setAdapter(customListViewAdapter);
}
// End of onCreate code. class
CustomListViewAdapter extends ArrayAdapter<String> {
ArrayList<String> nameArray;
ArrayList<String> modifiedArray; CustomListViewAdapter(Context c, ArrayList<String> name, ArrayList<String> lastmod) {
super(c, 0, name);
this.nameArray = name;
this.modifiedArray = lastmod;
}
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater=LayoutInflater.from(parent.get context());
convertView = inflater.inflate(R.layout.layout_item_view, parent, false);
TextView myName;
TextView myLastMod;
myName=(TextView) row.findViewById(R.id.rowtext);
myName.setText(nameArray.get(position));
myLastMod=(TextView) row.findViewById(R.id.textView6);
myLastMod.setText(modifiedArray.get(position));
return convertView;
}
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
getMenuInflater().inflate(R.menu.context_menu, menu);
}
@Override
public boolean onContextItemSelected(MenuItem itemMenu) {
switch (itemMenu.getItemId()) {
case R.id.context_menu_rename:
Toast.makeText(this, "Rename", Toast.LENGTH_SHORT).show();
break;
case R.id.context_menu_delete: itemNameArray.remove(listView.getSelectedItemPosition());
dateArray.remove(listView.getSelectedItemPosition()); customListViewAdapter.notifyDataSetChanged();
break;
}
return true;
}
}
问题是：我的 ContextMenu 无法使用自定义适配器从 ListView 中删除行，并且 应用程序崩溃并出现错误：UnsupportedOperationException，请参阅 Logcat 输出。
我进行了 Google 搜索并搜索了 Whosebug。 None 我找到的信息解决了这个问题。
我的问题是：我的代码有什么问题？ 请提供正确的代码来解决这个问题。
Java代码：
public class TestActivity extends ListActivity {
private String itemNameArray[];
private String dateArray[];
private ListView listview;
CustomListViewAdapter customListViewAdapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test);
registerForContextMenu(getListView());
root = Environment.getExternalStorageDirectory() + File.separator + "/ListTestFiles";
getDir(root);
listview = getListView();
name=itemNameArray;
lastmod=dateArray;
customListViewAdapter = new CustomListViewAdapter(this, name, lastmod);
listview.setAdapter(customListViewAdapter);
} // End of onCreate code.
class CustomListViewAdapter extends ArrayAdapter<String> {
Context context;
String[] nameArray;
String[] modifiedArray;
CustomListViewAdapter(Context c, String[] name, String[] lastmod)
{
super(c, R.layout.layout_item_view, R.id.rowtext, name);
this.context = c;
this.nameArray = name;
this.modifiedArray = lastmod;
}
public View getView(int position, View convertView, ViewGroup parent)
{
LayoutInflater inflater=(LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View row = inflater.inflate(R.layout.layout_item_view, parent, false);
TextView myName;
TextView myLastMod;
myName=(TextView) row.findViewById(R.id.rowtext);
myName.setText(nameArray[position]);
myLastMod=(TextView) row.findViewById(R.id.textView6);
myLastMod.setText(modifiedArray[position]);
return row;
}
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.context_menu, menu);
}
@Override
public boolean onContextItemSelected(MenuItem itemMenu) {
final AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo)itemMenu.getMenuInfo();
switch (itemMenu.getItemId()) {
case R.id.context_menu_rename:
Toast.makeText(this, "Rename", Toast.LENGTH_SHORT).show();
return true;
case R.id.context_menu_delete:
// NOTE TESTING the line of code below caused a runtime error: java.lang.UnsupportedOperationException
customListViewAdapter.remove(customListViewAdapter.getItem(info.position));
customListViewAdapter.notifyDataSetChanged();
Toast.makeText(getApplicationContext(), "position = " + info.position, Toast.LENGTH_SHORT).show();
Toast.makeText(this, "Delete", Toast.LENGTH_SHORT).show();
return true;
return super.onContextItemSelected(itemMenu);
}
}
}
Logcat 输出：
11-13 10:45:21.229 21432-21432/com.testing.listapp D/AndroidRuntime﹕ Shutting down VM
--------- beginning of crash
11-13 10:45:21.246 21432-21432/com.testing.listapp E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.testing.listapp, PID: 21432
java.lang.UnsupportedOperationException
at java.util.AbstractList.remove(AbstractList.java:638)
at java.util.AbstractList$SimpleListIterator.remove(AbstractList.java:75)
at java.util.AbstractCollection.remove(AbstractCollection.java:229)
at android.widget.ArrayAdapter.remove(ArrayAdapter.java:244)
at com.testing.listapp.TestActivity.onContextItemSelected(TestActivity.java:5468)
at android.app.Activity.onMenuItemSelected(Activity.java:2905)
at com.android.internal.policy.impl.PhoneWindow$DialogMenuCallback.onMenuItemSelected(PhoneWindow.java:4701)
at com.android.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:761)
at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:152)
at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:904)
at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:894)
at com.android.internal.view.menu.MenuDialogHelper.onClick(MenuDialogHelper.java:167)
at com.android.internal.app.AlertController$AlertParams.onItemClick(AlertController.java:1082)
at android.widget.AdapterView.performItemClick(AdapterView.java:305)
at android.widget.AbsListView.performItemClick(AbsListView.java:1146)
at android.widget.AbsListView$PerformClick.run(AbsListView.java:3053)
at android.widget.AbsListView.run(AbsListView.java:3860)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
只需从 nameArray 和 modifiedArray 中删除特定位置的项目，然后通知 adapter数据集更改。
我明白了。一个大错误是在需要动态大小数组的地方使用固定大小数组。
改变你的
String nameArray[];
String modifiedArray[];
至
ArrayList<String> nameArray;
ArrayList<String> modifiedArray;
我修改了你的作品：
public class TestActivity extends ListActivity {
private ArrayList<String> itemNameArray;
private ArrayList<String> dateArray;
private ListView listview;
CustomListViewAdapter customListViewAdapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test);
registerForContextMenu(getListView());
String root = Environment.getExternalStorageDirectory() + File.separator + "/ListTestFiles";
getDir(root);
listview = getListView();
CustomListViewAdapter = new CustomListViewAdapter(this, itemNameArray, dateArray);
listview.setAdapter(customListViewAdapter);
}
// End of onCreate code. class
CustomListViewAdapter extends ArrayAdapter<String> {
ArrayList<String> nameArray;
ArrayList<String> modifiedArray; CustomListViewAdapter(Context c, ArrayList<String> name, ArrayList<String> lastmod) {
super(c, 0, name);
this.nameArray = name;
this.modifiedArray = lastmod;
}
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater inflater=LayoutInflater.from(parent.get context());
convertView = inflater.inflate(R.layout.layout_item_view, parent, false);
TextView myName;
TextView myLastMod;
myName=(TextView) row.findViewById(R.id.rowtext);
myName.setText(nameArray.get(position));
myLastMod=(TextView) row.findViewById(R.id.textView6);
myLastMod.setText(modifiedArray.get(position));
return convertView;
}
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
getMenuInflater().inflate(R.menu.context_menu, menu);
}
@Override
public boolean onContextItemSelected(MenuItem itemMenu) {
switch (itemMenu.getItemId()) {
case R.id.context_menu_rename:
Toast.makeText(this, "Rename", Toast.LENGTH_SHORT).show();
break;
case R.id.context_menu_delete: itemNameArray.remove(listView.getSelectedItemPosition());
dateArray.remove(listView.getSelectedItemPosition()); customListViewAdapter.notifyDataSetChanged();
break;
}
return true;
}
}