我的适配器无法正确更新我的listview选项

问题描述 投票:1回答:2

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

enter image description here

恰好通过删除第4项来选择第5项的复选框

enter image description here

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();
}
android android-listview android-arrayadapter
2个回答
3
投票

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。


0
投票

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);
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