GWT标头复选框可以选中/取消选中表中的所有复选框

问题描述

我已经使用Google Web Toolkit创建了一个CellTable.我刚刚开始使用它，而我对此的了解非常少.但是，我在搜索有关如何在CellTable标题中创建复选框的教程或代码示例，但我发现的所有内容我都不理解或不起作用.

到目前为止，我已经获得了以下代码来为复选框和普通表创建一个Column，该普通表与CellTable的Google教程基本相同:

  Column< Contact，Boolean>checkColumn = new Column< Contact，Boolean>(new CheckboxCell(true，false)){@Overridepublic Boolean getValue(Contact contact){返回null；}};table.addColumn(checkColumn，SafeHtmlUtils.fromSafeConstant(< br/&";)));table.setColumnWidth(checkColumn，40，Unit.PX); 

现在，我正在搜索要在标题中添加复选框的代码，以及如何使其选中或取消选中所有复选框.

感谢您的时间.

解决方案

来自

我正在使用选择模型和数据列表提供程序来完成选择魔术.可能并不适合所有人.

这是我的自定义标头:

 公共最终类CheckboxHeader扩展了Header {私有最终MultiSelectionModel selectionModel;私有的最终ListDataProvider提供程序；公共CheckboxHeader(MultiSelectionModel selectionModel，ListDataProvider提供程序){超级(新CheckboxCell());this.selectionModel = selectionModel;this.provider =提供程序；}@Overridepublic Boolean getValue(){boolean allItemsSelected = selectionModel.getSelectedSet().size()==提供程序.getList().size();返回allItemsSelected;}@Override公共无效onBrowserEvent(上下文上下文，元素elem，NativeEvent事件){InputElement输入= elem.getFirstChild().cast();布尔值isChecked = input.isChecked();对于(TYPE元素:provider.getList()){selectionModel.setSelected(element，isChecked);}}} 

I´ve created an CellTable with the Google Web Toolkit.I just started using it and my knowledge about it is very small...However I was searching for a tutorial or just a code example of how to create a checkbox in the CellTable header but everythin I´ve found I didn´t understand or it didn´t worked.

So far I´ve got this code to create a Column for checkboxes and a normal table mostly the same as the Google tutorial for a CellTable:

Column<Contact, Boolean> checkColumn = new Column<Contact, Boolean>(
new CheckboxCell(true, false)) {

@Override
public Boolean getValue(Contact contact) {
    return null;
}

};

table.addColumn(checkColumn, SafeHtmlUtils.fromSafeConstant("<br/>"));
table.setColumnWidth(checkColumn, 40, Unit.PX);

Now I´m searching for the code to add a checkbox to the header and how to make it check or uncheck all checkboxes.

Thanks for your time.

解决方案

From my blog post:

Here is a simple column header that selects/ de-selects all rows in a table. When all rows are checked, the header becomes checked automatically. Clicking the checkbox in the header causes either to select or de-select all rows.

I am using the selection model and the data list provider to do the selection magic. It may not work for everyone.

And here is my custom header:

public final class CheckboxHeader extends Header {

    private final MultiSelectionModel selectionModel;
    private final ListDataProvider provider;

    public CheckboxHeader(MultiSelectionModel selectionModel,
            ListDataProvider provider) {
        super(new CheckboxCell());
        this.selectionModel = selectionModel;
        this.provider = provider;
    }

    @Override
    public Boolean getValue() {
        boolean allItemsSelected = selectionModel.getSelectedSet().size() == provider
                .getList().size();
        return allItemsSelected;
    }

    @Override
    public void onBrowserEvent(Context context, Element elem, NativeEvent event) {
        InputElement input = elem.getFirstChild().cast();
        Boolean isChecked = input.isChecked();
        for (TYPE element : provider.getList()) {
            selectionModel.setSelected(element, isChecked);
        }
    }

}

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