我有下一个问题。当我从我的适配器中的ListView中删除一个项目时,CheckBox的状态从列表中的项目改变,为什么?而且,怎么能解决这个问题呢?
public class CustomAdapter extends ArrayAdapter<RowModel> implements View.OnClickListener {
private ArrayList<RowModel> DataSet;
Context context;
public CustomAdapter(ArrayList<RowModel> data, Context context) {
super(context, R.layout.list_item_main, data);
this.DataSet = data;
this.context = context;
}
@Override
public void onClick(View v) {
int position = (Integer) v.getTag();
Object object = getItem(position);
RowModel dataRowModel = (RowModel) object;
switch (v.getId()) {
case R.id.list_checkbox:
CheckBox checkBox = v.findViewById(R.id.list_checkbox);
int bool = (checkBox.isChecked()) ? 1 : 0;
new ListFacade(context).UpdateState(dataRowModel.getRowid(), bool);
break;
case R.id.list_delete_button:
new ListFacade(context).DeleteRow(dataRowModel.getRowid());
DataSet.remove(object);
break;
}
notifyDataSetChanged();
updateWidgetToChange();
}
如果我删除项目4
恰好通过删除第4项来选择第5项的复选框
编辑1:添加了getView
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// Get the data item for this position
RowModel dataRowModel = getItem(position);
// Check if an existing view is being reused, otherwise inflate the view
ViewHolder viewHolder; // view lookup cache stored in tag
if (convertView == null) {
viewHolder = new ViewHolder();
LayoutInflater inflater = LayoutInflater.from(getContext());
convertView = inflater.inflate(R.layout.list_item_main, parent, false);
viewHolder.checkbox = convertView.findViewById(R.id.list_checkbox);
viewHolder.checkbox.setChecked(dataRowModel.isChecked());
viewHolder.title = convertView.findViewById(R.id.list_title);
viewHolder.classes = convertView.findViewById(R.id.list_classes);
viewHolder.rowid = convertView.findViewById(R.id.list_rowid);
viewHolder.delete_button = convertView.findViewById(R.id.list_delete_button);
convertView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) convertView.getTag();
}
viewHolder.rowid.setText(dataRowModel.getStringRowid());
viewHolder.title.setText(dataRowModel.getAction());
viewHolder.classes.setText(dataRowModel.getType());
viewHolder.checkbox.setOnClickListener(this);
viewHolder.checkbox.setTag(position);
viewHolder.delete_button.setOnClickListener(this);
viewHolder.delete_button.setTag(position);
// Return the completed view to render on screen
return convertView;
}
编辑2:添加了ListFacade
public void UpdateState(int rowid, int bool){
SQLiteDatabase conn = new SqliteHandler(context).getWritableDatabase();
String strSQL = "UPDATE TODO_LIST SET CHECKED='"+ bool +"' WHERE ROWID = "+ rowid;
conn.execSQL(strSQL);
conn.close();
}
public void DeleteRow(int rowid){
SQLiteDatabase conn = new SqliteHandler(context).getWritableDatabase();
conn.delete("TODO_LIST", "ROWID=?", new String[]{String.valueOf(rowid)});
conn.close();
}
只是猜测,但我认为你需要在getView-method中更新复选框的状态。从dataSet中删除对象时,需要确保在getView方法中更新了isChecked。现在,当您从dataSet中删除一个数据并更新列表项时,CheckBox的状态不会更改。
你的代码中有这样的东西吗?:
@Override
public View getView(int position, View convertView, @NonNull ViewGroup parent) {
// Other code...
RowModel model = getItem(position);
CheckBox cb = (CheckBox) convertView.findViewById(R.id.list_checkbox);
cb.setChecked(model.isChecked());
// ...
}
因为我发现你没有在CheckBox的点击监听器中更新数据集。
所以你需要在里面添加这个,或者类似的东西:
case R.id.list_checkbox:
CheckBox checkBox = v.findViewById(R.id.list_checkbox);
dataRowModel.isChecked(checkBox.isChecked());
// ... rest of the code
编辑:
问题是,当View(convertView)为null时,您只更新CheckBox!您需要将该代码从if(convertView == null)移开,因为它仅在创建View时调用,并且当您调用notifyDataSetChanged时,不会再次创建Views并且未到达if块。
要添加到@ vilpe89的答案,问题不是你没有在setChecked()
中调用getView()
,而是你在错误的位置调用它:
viewHolder.checkbox.setChecked(dataRowModel.isChecked());
只有在convertView == null
时才调用此行,但更新列表时convertView
不会为null。因此,要解决您的问题,您需要将该行移到if else
语句之后,如下所示:
viewHolder.checkbox.setOnClickListener(this);
viewHolder.checkbox.setChecked(dataRowModel.isChecked());
viewHolder.checkbox.setTag(position);