Question

我已经创建了一个自定义列表视图，我想在列表视图中预先选择一个项目。我在网上尝试了很多事情，但是没有运气。下面给出了我的尝试。

lvModifierSet.requestFocusFromTouch();

lvModifierSet.setSelection(1);

lvModifierSet.setItemChecked(1, true);

lvModifierSet.performItemClick(lvModifierSet.getChildAt(1), 1, lvModifierSet.getItemIdAtPosition(1));

这是我的列表视图

<ListView
            android:id="@+id/menu_lv_modifier_set"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_marginEnd="1dp"
            android:layout_marginRight="1dp"
            android:layout_marginTop="1dp"
            android:layout_weight="1"
            android:background="@color/colorWhite"
            android:divider="@color/colorLightGray"
            android:dividerHeight="1dp"
            android:listSelector="@color/colorLightGray" />

自定义适配器代码

public class ModifierSetListAdapter extends ArrayAdapter<ModifierSet> {

    private Context context;
    private int resourceLayout;
    private List<ModifierSet> modifierSets;

    public ModifierSetListAdapter(Context context, int resource, List<ModifierSet> modifierSets) {
        super(context, resource, modifierSets);
        this.context = context;
        resourceLayout = resource;
        this.modifierSets = modifierSets;
    }

    @Nullable
    @Override
    public ModifierSet getItem(int position) {
        return modifierSets.get(position);
    }

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

        View view = convertView;
        if (view == null) {
            LayoutInflater vi = LayoutInflater.from(context);
            view = vi.inflate(resourceLayout, null);
        }

        ModifierSet modifierSet = modifierSets.get(position);
        view.setId(modifierSet.getMenu_modifier_set_id());


        TextView tvModifierName = view.findViewById(R.id.modifier_set_tv_modifier_name);
        tvModifierName.setText(modifierSet.getModifier_set_name());

        return view;

    }

}

Answer 1

使用Runnable()尝试类似的事情：

lvModifierSet.post(new Runnable() {

        @Override
        public void run() {
            lvModifierSet.requestFocusFromTouch();
            lvModifierSet.setSelection(1);
        }
    });

Answer 2

您需要使用ArrayList进行操作。在模型类中添加isSelected布尔参数，如下所示：-

private boolean isSelected;


public boolean isSelected() {
      return isSelected;
}

public void setIsSelected(boolean isSelected) {
      isSelected = isSelected;
}

在您的 Java 类中，我们需要分配特定的项目（已选择或未选择）。

YOUR_ARRAYLIST.get(POSITION_WHICH_U_WANT_TO_SELECT).setIsSelected(true);

在适配器类的getView方法中，您需要检查视图是否为 SELECTED 或 UN-SELECTED

  public View getView(int position, View convertView, ViewGroup parent) {
            // Get the data item for this position
            ModifierSet dataModel = getItem(position);
            // Check if an existing view is being reused, otherwise inflate the view
            ViewHolder viewHolder; // view lookup cache stored in tag

            final View result;

            if (convertView == null) {

                viewHolder = new ViewHolder();
                LayoutInflater inflater = LayoutInflater.from(getContext());
                convertView = inflater.inflate(R.layout.row_item, parent, false);

                result=convertView;
                convertView.setTag(viewHolder);
            } else {
                viewHolder = (ViewHolder) convertView.getTag();
                result=convertView;
            }

        if(dataModel.get(position).isSelected())
          {
            /**
             * SET THE LISTVIEW'S ITEM SELECTED HERE
             */

          }
         else
          {
            /**
             * SET THE LISTVIEW'S ITEM UN-SELECTED HERE
             */
          }  
      }

如何预先选择一个列表视图行？

2 个答案: