VaAdin生成的页面不显示任何组件

我一般对vaadin框架有问题。

我创建了一个扩展vaadin应用程序的类(MyFirst)，之后我使用vaadin可视化设计器(MyFormApp)创建了一个自定义组件。

我确实实例化了自定义组件MyFormApp，并将其添加到MyFirst的主窗口。

部署应用后，vaadin生成的页面不显示任何组件。

我的代码：

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package com.example.vaadin;

import com.vaadin.Application;
import com.vaadin.ui.*;

/**
*
* @author anis.bouchenafa
*/
public class MyFirst extends Application{


private Button newContact = new Button("Add contact");
private Button search = new Button("Search");
private Button share = new Button("Share");
private Button help = new Button("Help");
private HorizontalSplitPanel horizontalSplit = new HorizontalSplitPanel();
private TextField tf = new TextField();

@Override
public void init() {
    //buildMainLayout();

    MyFirstApp a = new MyFirstApp();
   Window w = new Window("aness conf");
   w.addComponent(a);
   setMainWindow(w);


}

}

我的第二个类是MyFirstApp(自定义组件)：

package com.example.vaadin;



import com.vaadin.annotations.AutoGenerated;
import com.vaadin.ui.AbsoluteLayout;
import com.vaadin.ui.CustomComponent;
import com.vaadin.ui.LoginForm;

public class MyFirstApp extends CustomComponent {

@AutoGenerated
private AbsoluteLayout mainLayout;
@AutoGenerated
private LoginForm loginForm_2;

/*- VaadinEditorProperties=        {"grid":"RegularGrid,20","showGrid":true,"snapToGrid":true,"snapToObject":true,"movingGuides":false,"snappingDistance":10} */



/*- VaadinEditorProperties={"grid":"RegularGrid,20","showGrid":true,"snapToGrid":true,"snapToObject":true,"movingGuides":false,"snappingDistance":10} */

/**
 * The constructor should first build the main layout, set the
 * composition root and then do any custom initialization.
 *
 * The constructor will not be automatically regenerated by the
 * visual editor.
 */
public MyFirstApp() {
    buildMainLayout();
    setCompositionRoot(mainLayout);

    // TODO add user code here
}

@AutoGenerated
private AbsoluteLayout buildMainLayout() {
    // common part: create layout
    mainLayout = new AbsoluteLayout();
    mainLayout.setImmediate(false);
    mainLayout.setWidth("100%");
    mainLayout.setHeight("100%");

    // top-level component properties
    setWidth("100.0%");
    setHeight("100.0%");

    // loginForm_2
    loginForm_2 = new LoginForm();
    loginForm_2.setStyleName("v-loginform");
    loginForm_2.setImmediate(false);
    loginForm_2.setWidth("340px");
    loginForm_2.setHeight("-1px");
    mainLayout.addComponent(loginForm_2, "top:160.0px;left:200.0px;");

    return mainLayout;
}

}

执行Servlet后，浏览器上不显示任何内容。

---

解决方案

好的，您调用buildMainLayout()，它在视觉上是空的。它只包含一个AbsoluteLayout和一个LoginForm()，其中没有任何组件。这就像生成一个无边框的HTML表，而不添加任何文本。

我认为您要添加的组件

private Button newContact = new Button("Add contact");
private Button search = new Button("Search");
private Button share = new Button("Share");
private Button help = new Button("Help");
private HorizontalSplitPanel horizontalSplit = new HorizontalSplitPanel();
private TextField tf = new TextField();

应

1. 在"类MyFirstApp"中声明并初始化
2. 通过addComponent()添加到布局

详细布局(和其他基础知识)也在Vaadin书中介绍：

瓦丁之书：https://vaadin.com/book/-/page/intro.html

瓦丁之书-布局：Layout:https://vaadin.com/book/-/page/layout.html

Vaadin布局示例：http://demo.vaadin.com/sampler#Layouts