Question

我有一个arraylist，其中长按一个元素，它显示一个上下文菜单，我可以删除或编辑arraylist的选定项目。

我有疑问，我如何定义我选择的项目，编辑或删除它？

这些是上下文菜单中引用的方法。这是我第一次使用这个菜单而我还没有测试过功能，所以这些方法可能都是错误的。

@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
    super.onCreateContextMenu(menu, v, menuInfo);

    AdapterView.AdapterContextMenuInfo info;
    info = (AdapterView.AdapterContextMenuInfo) menuInfo;

    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.context_menu, menu);
}

@Override
public boolean onContextItemSelected(MenuItem item) {

    AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();
    switch (item.getItemId()) {
        case R.id.edit_travel:

            return true;
        case R.id.delete_travel:

            return true;
        default:
            return super.onContextItemSelected(item);
    }
}

正如我所说，我认为错过了确定我想编辑或删除哪个arraylist元素的方法，但我不知道如何定义

更新 - 添加代码

public class TravelListActivity extends ListActivity {

private static final int REQUEST_CODE_CREATE_TRAVEL = 0;
private TravelAdapter adapter;

private class TravelAdapter extends ArrayAdapter<TravelInfo>{

    private final Context context;
    private final ArrayList<TravelInfo> travels;
    private static final int RESOURCE = android.R.layout.simple_list_item_2;

    public TravelAdapter(Context context, ArrayList<TravelInfo> travels) {
        super(context, RESOURCE, travels);

        this.context = context;
        this.travels = travels;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        LinearLayout view;
        ViewHolder holder;

        if (convertView == null){
            view = new LinearLayout(context);

            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            inflater.inflate(RESOURCE, view, true);

            holder = new ViewHolder();
            holder.text1 = (TextView) view.findViewById(android.R.id.text1);
            holder.text2 = (TextView) view.findViewById(android.R.id.text2);
            view.setTag(holder);

        } else {
            view = (LinearLayout) convertView;
            holder = (ViewHolder) view.getTag();
        }

        TravelInfo info = travels.get(position);
        holder.text1.setText(info.getCity() + " (" + info.getCountry() + ")");
        holder.text2.setText(getResources().getString(R.string.year) + " " + info.getYear());

        return view;
    }

}

static class ViewHolder {
    TextView text1;
    TextView text2;
}


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    registerForContextMenu(getListView());

Answer 1

您可以通过以下行获得item长按：

TravelInfo itemSelected = adapter.getItem(info.position);

示例：

@Override
public boolean onContextItemSelected(MenuItem item) {

    AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();
    TravelInfo itemSelected = adapter.getItem(info.position);
    switch (item.getItemId()) {
        case R.id.edit_travel:

            return true;
        case R.id.delete_travel:

            return true;
        default:
            return super.onContextItemSelected(item);
    }
}

注意：要使其工作（1），您应该通过调用adapter <onCreate（2）设置列表适配器初始化setAdapter(adapter) / p>

Answer 2

您可以获取所选行列表视图的位置：

 @Override
 public boolean onContextItemSelected(MenuItem item) {
    AdapterContextMenuInfo info = (AdapterContextMenuInfo) item
                    .getMenuInfo();

    switch (item.getItemId()) {
       case R.id.edit_travel:
       Toast.makeText(getBaseContext(), "edit: "+info.position, Toast.LENGTH_SHORT).show();
            return true;
       case R.id.delete_travel:
       Toast.makeText(getBaseContext(), "delete: "+info.position, Toast.LENGTH_SHORT).show();
            return true;
                             }
            return false;
        }

获取位置后，从该位置的Arraylist更新它。现在，请致电notifyDataSetChanged :: youradapter.notifyDataSetChanged();

从arraylist中删除或编辑元素

2 个答案: