处理onClick以查看CellTable标头中的复选框

Question

我正在尝试创建一个包含一些文本和一个复选框的列的CellTable,它将用作全选复选框(参见下图,"cb"是复选框).目前我正在使用从Header派生的类并覆盖它的render方法来输出文本和一个复选框.我重写onBrowserEvent()但它只给我onChange事件,除了复选框无法正常工作外,它会正常工作.有没有人对此有任何想法？

+-------+------------+
| col 1 | Select All |
|       |     cb     | 
+-------+------------+
| row 1 |     cb     |
+-------+------------+

我在复选框中遇到的问题是,如果没有选中,则必须单击两次以显示复选标记(至少在Chrome上),即使第一次"已检查"属性为真.单击一下即可正确取消选中它.

这是一些代码:

设置CellTable列:

/** Setup the table's columns. */
private void setupTableColumns() {
    // Add the first column:
    TextColumn<MyObject> column1 = new TextColumn<MyObject>() {
        @Override
        public String getValue(final MyObject object) {
            return object.getColumn1Text();
        }
    };
    table.addColumn(macColumn, SafeHtmlUtils.fromSafeConstant("Column1"));

    // the checkbox column for selecting the lease
    Column<MyObject, Boolean> checkColumn = new Column<MyObject, Boolean>(
            new CheckboxCell(true, false)) {
        @Override
        public Boolean getValue(final MyObject object) {
            return selectionModel.isSelected(object);
        }
    };

    SelectAllHeader selectAll = new SelectAllHeader();
    selectAll.setSelectAllHandler(new SelectHandler());
    table.addColumn(checkColumn, selectAll);
}

我选择所有标题:

public static class SelectAllHeader extends Header<Boolean> {
    private final String checkboxID = "selectAllCheckbox";
    private ISelectAllHandler handler = null;

    @Override
    public void render(final Context context, final SafeHtmlBuilder sb) {
        String html = "<div>Select All<div><input type=\"checkbox\" id=\"" + checkboxID + "\"/>";

        sb.appendHtmlConstant(html);
    }

    private final Boolean allSelected;

    public SelectAllHeader() {
        super(new CheckboxCell());

        allSelected = false;
    }

    @Override
    public Boolean getValue() {
        Element checkboxElem = DOM.getElementById(checkboxID);

        return checkboxElem.getPropertyBoolean("checked");

    }

    @Override
    public void onBrowserEvent(final Context context, final Element element, final NativeEvent event) {
        Event evt = Event.as(event);
        int eventType = evt.getTypeInt();

        super.onBrowserEvent(context, element, event);

        switch (eventType) {
            case Event.ONCHANGE:
                handler.onSelectAllClicked(getValue());
                event.preventDefault();
                break;

            default:
                break;
        }

    }


    public void setSelectAllHandler(final ISelectAllHandler handler) {
        this.handler = handler;
    }

}

Answer 1

每当渲染标题时,您似乎都会渲染一个未选中的复选框,这可能会在每个单元格重新渲染时消除选择状态.

尝试存储已检查状态并使用状态呈现复选框.看起来你已经走了一半allSelected,你只是没有使用它.

编辑这是我刚刚为Zanata编写的一个工作实现(请参阅SearchResultsView.java).实现HasValue接口,以便可以以标准方式处理值更改事件.我没有覆盖渲染方法,如果你想这样做,请确保getValue()用于确定是否渲染已选中或未选中的复选框.选择/取消选择逻辑在相关的演示者类中处理(请参阅SearchResultsPresenter.java).

private class CheckboxHeader extends Header<Boolean> implements HasValue<Boolean> {

   private boolean checked;
   private HandlerManager handlerManager;

   public CheckboxHeader()
   {
      //TODO consider custom cell with text
      super(new CheckboxCell());
      checked = false;
   }

   // This method is invoked to pass the value to the CheckboxCell's render method
   @Override
   public Boolean getValue()
   {
      return checked;
   }

   @Override
   public void onBrowserEvent(Context context, Element elem, NativeEvent nativeEvent)
   {
      int eventType = Event.as(nativeEvent).getTypeInt();
      if (eventType == Event.ONCHANGE)
      {
         nativeEvent.preventDefault();
         //use value setter to easily fire change event to handlers
         setValue(!checked, true);
      }
   }

   @Override
   public HandlerRegistration addValueChangeHandler(ValueChangeHandler<Boolean> handler)
   {
      return ensureHandlerManager().addHandler(ValueChangeEvent.getType(), handler);
   }

   @Override
   public void fireEvent(GwtEvent<?> event)
   {
      ensureHandlerManager().fireEvent(event);
   }

   @Override
   public void setValue(Boolean value)
   {
      checked = value;
   }

   @Override
   public void setValue(Boolean value, boolean fireEvents)
   {
      checked = value;
      if (fireEvents)
      {
         ValueChangeEvent.fire(this, value);
      }
   }

   private HandlerManager ensureHandlerManager()
   {
      if (handlerManager == null)
      {
         handlerManager = new HandlerManager(this);
      }
      return handlerManager;
   }
}