在单个GWT UiBinder模板中使用带有小部件的TreeItem作为内容

我正试图使用在UI活页夹模板中定义为

TreeItem

内容的

Widget

初始化

TreeItem

。最初，我使用的模板如下：

<g:Tree>
    <g:TreeItem>
        <g:HTMLPanel>
            <p>This is the root item's content.</p>
        </g:HTMLPanel>
        <g:TreeItem>
            <g:HTMLPanel>
                <p>This is the child's content.</p>
            </g:HTMLPanel>
        </g:TreeItem>
    </g:TreeItem>
</g:Tree>

+ This is the root item's content.

- (root item has no content)
 \ This is the root item's content.
  - (first child has no content)
   \ This is the child's content.

<g:Tree>
    <c:WidgetTreeItem>
        <c:widget>
            <g:HTMLPanel>
                <p>This is the root item's content.</p>
            </g:HTMLPanel>
        </c:widget>
        <!-- Should create a child TreeItem with the HTMLPanel as its Widget. -->
        <g:HTMLPanel>
            <p>This is the child's content.</p>
        </g:HTMLPanel>
    </c:WidgetTreeItem>
</g:Tree>

<g:Tree>
    <g:HTMLPanel ui:field="rootContent">
        <p>This is the root item's content.</p>
    </g:HTMLPanel>
    <g:HTMLPanel ui:field="childContent">
        <p>This is the child's content.</p>
    </g:HTMLPanel>
    <g:TreeItem widget="{rootContent}">
        <g:TreeItem widget="{childContent}">
        </g:TreeItem>
    </g:TreeItem>
</g:Tree>

扩展到：

- This is the root item's content.
 \ This is the child's content.

但这不起作用。

HTMLPanel

小部件是作为

TreeItem

s的子项创建的，而不是作为项的小部件，因此我最终得到如下结构：

<g:Tree>
    <g:TreeItem>
        <g:HTMLPanel>
            <p>This is the root item's content.</p>
        </g:HTMLPanel>
        <g:TreeItem>
            <g:HTMLPanel>
                <p>This is the child's content.</p>
            </g:HTMLPanel>
        </g:TreeItem>
    </g:TreeItem>
</g:Tree>

+ This is the root item's content.

- (root item has no content)
 \ This is the root item's content.
  - (first child has no content)
   \ This is the child's content.

<g:Tree>
    <c:WidgetTreeItem>
        <c:widget>
            <g:HTMLPanel>
                <p>This is the root item's content.</p>
            </g:HTMLPanel>
        </c:widget>
        <!-- Should create a child TreeItem with the HTMLPanel as its Widget. -->
        <g:HTMLPanel>
            <p>This is the child's content.</p>
        </g:HTMLPanel>
    </c:WidgetTreeItem>
</g:Tree>

<g:Tree>
    <g:HTMLPanel ui:field="rootContent">
        <p>This is the root item's content.</p>
    </g:HTMLPanel>
    <g:HTMLPanel ui:field="childContent">
        <p>This is the child's content.</p>
    </g:HTMLPanel>
    <g:TreeItem widget="{rootContent}">
        <g:TreeItem widget="{childContent}">
        </g:TreeItem>
    </g:TreeItem>
</g:Tree>

因此我尝试扩展

TreeItem

类，如下所示：

public class WidgetTreeItem extends TreeItem {

    @UiChild(tagname="widget", limit=1)
    public void setWidget(IsWidget isWidget) {
        super.setWidget(isWidget.asWidget());
    }

}

然后，将包含

widgetreeitem

的包导入

c

命名空间，我有一个如下模板：

<g:Tree>
    <g:TreeItem>
        <g:HTMLPanel>
            <p>This is the root item's content.</p>
        </g:HTMLPanel>
        <g:TreeItem>
            <g:HTMLPanel>
                <p>This is the child's content.</p>
            </g:HTMLPanel>
        </g:TreeItem>
    </g:TreeItem>
</g:Tree>

+ This is the root item's content.

- (root item has no content)
 \ This is the root item's content.
  - (first child has no content)
   \ This is the child's content.

<g:Tree>
    <c:WidgetTreeItem>
        <c:widget>
            <g:HTMLPanel>
                <p>This is the root item's content.</p>
            </g:HTMLPanel>
        </c:widget>
        <!-- Should create a child TreeItem with the HTMLPanel as its Widget. -->
        <g:HTMLPanel>
            <p>This is the child's content.</p>
        </g:HTMLPanel>
    </c:WidgetTreeItem>
</g:Tree>

<g:Tree>
    <g:HTMLPanel ui:field="rootContent">
        <p>This is the root item's content.</p>
    </g:HTMLPanel>
    <g:HTMLPanel ui:field="childContent">
        <p>This is the child's content.</p>
    </g:HTMLPanel>
    <g:TreeItem widget="{rootContent}">
        <g:TreeItem widget="{childContent}">
        </g:TreeItem>
    </g:TreeItem>
</g:Tree>

这是根项目的内容

这是孩子的内容

但这也不行。它失败，但出现以下异常：

只有TreeItem或Widget子类是有效的子类：

---

有人知道如何实现我的目标吗？

从中得到一些启发，我找到了解决方案。在我最初的示例中，XML现在如下所示：

<g:Tree>
    <g:TreeItem>
        <g:HTMLPanel>
            <p>This is the root item's content.</p>
        </g:HTMLPanel>
        <g:TreeItem>
            <g:HTMLPanel>
                <p>This is the child's content.</p>
            </g:HTMLPanel>
        </g:TreeItem>
    </g:TreeItem>
</g:Tree>

+ This is the root item's content.

- (root item has no content)
 \ This is the root item's content.
  - (first child has no content)
   \ This is the child's content.

<g:Tree>
    <c:WidgetTreeItem>
        <c:widget>
            <g:HTMLPanel>
                <p>This is the root item's content.</p>
            </g:HTMLPanel>
        </c:widget>
        <!-- Should create a child TreeItem with the HTMLPanel as its Widget. -->
        <g:HTMLPanel>
            <p>This is the child's content.</p>
        </g:HTMLPanel>
    </c:WidgetTreeItem>
</g:Tree>

<g:Tree>
    <g:HTMLPanel ui:field="rootContent">
        <p>This is the root item's content.</p>
    </g:HTMLPanel>
    <g:HTMLPanel ui:field="childContent">
        <p>This is the child's content.</p>
    </g:HTMLPanel>
    <g:TreeItem widget="{rootContent}">
        <g:TreeItem widget="{childContent}">
        </g:TreeItem>
    </g:TreeItem>
</g:Tree>

这是根项目的内容

这是孩子的内容

---

这里需要一些游戏。最值得注意的是，只有当内容面板包含在实现

haswidget

接口的小部件中时，这才有效。

树

类满足此要求。同样值得注意的是，在使用内容字段之前，必须对其进行定义。

以下内容可能会对您有所帮助

<g:Tree>
    <g:TreeItem text="This is the first parent item's content.">
        <g:TreeItem text="This is the child 1's content." />
        <g:TreeItem text="This is the child 2's content." />

    </g:TreeItem>

    <g:TreeItem text="This is the second parent item's content.">
        <g:TreeItem text="This is the child 3's content." />
        <g:TreeItem text="This is the child 4's content." />

    </g:TreeItem>
</g:Tree>

---

您可以根据需要添加任意数量的树项。

这是我的方法，问题是，实际上，内容包含复杂的小部件，而不仅仅是文本。本质上，我是在寻找一种使用

TreeItem（Widget w）

构造函数的方法。一旦我了解了如何构造模板，我提供的自我回答就完全达到了预期的效果。