Vaadin8声明与NativeSelect无法正常工作

Question

我使用以下4行代码成功在vaadin java web应用程序中设置NativeSelect，并且我的enum（ApplicationStatus）创建并填充了NativeSelect菜单。

当我尝试在声明文件中执行相同操作时，NativeSelect菜单显示为空。

class Application extends VerticalLayout
{
public Application()
{
..
    //ApplicationStatus is an enum, these exact four lines of code work fine without declarative

    private NativeSelect<ApplicationStatus> categorySelect = new NativeSelect<ApplicationStatus>("Application Status");

    categorySelect.setItems( ApplicationStatus.values());
    categorySelect.setItemCaptionGenerator( ApplicationStatus::getName );
    categorySelect.setSelectedItem(ApplicationStatus.ACTIVE);

..
}

这是声明性HTML文件（ATTEMPT1） //菜单显示为空

...

    <row>
      <column><vaadin-label><strong>Decline Reason</strong></vaadin-label></column>
    <column><v-native-select _id="categorySelect"></v-native-select></column>
    </row>

...

**Here is the Declarative  HTML FILE  (ATTEMPT2)** //I tried populating it inline but the result was that the menu now has the word "Duplicate" showing 5 times.
...
        <row>
         <column><vaadin-label><strong>Change Category</strong></vaadin-label></column>
         <column><vaadin-native-select _id="categorySelect">
                <option value="D">Decline</option>
                <option value="W">Waitlist</option>
                <option value="R">Rejected by VCS</option>
                <option value="P">Prospect</option>
                <option value="C">Duplicate</option>
                </vaadin-native-select></column>
        </row>

...

Answer 1

你没有为声明性实现包含Java源代码，所以只是试着去做。

在类对象中声明NativeSelect变量，用于定义它所在的布局。让设计使用您提供的_id将变量绑定到声明。然后使用枚举填充控件并像以前一样指定默认值。

NativeSelect<ApplicationStatus> categorySelect;

public DemoView()
{
    Design.read( "DemoView.html", this );

    categorySelect.setItems( ApplicationStatus.values() );
    categorySelect.setSelectedItem( ApplicationStatus.ACTIVE );

这会产生一个带有所需字幕和枚举映射的选择控件。

我追踪了一些Vaadin代码，我不确定是否有办法用纯粹使用声明性方法的枚举填充控件。