Vaadin - 佈局元件

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佈局元件充當佔位符，用於在前端儲存和表示資料。本章，我們將學習 VAADIN 中不同型別的佈局元件。

垂直和水平佈局

垂直和水平佈局是有序佈局，幫助使用者以垂直或水平方式呈現資料。我們已經在之前看到的許多示例中使用了這個概念。以下示例將向您展示如何在 Vaadin 應用程式中使用它。

package com.TutorialsMy.myApp;

import javax.servlet.annotation.WebServlet;
import com.vaadin.annotations.Theme;
import com.vaadin.annotations.VaadinServletConfiguration;
import com.vaadin.server.VaadinRequest;
import com.vaadin.server.VaadinServlet;
import com.vaadin.shared.ui.ContentMode;
import com.vaadin.ui.Button;
import com.vaadin.ui.HorizontalLayout;
import com.vaadin.ui.Label;
import com.vaadin.ui.TextField;
import com.vaadin.ui.UI;
import com.vaadin.ui.VerticalLayout;

@Theme("mytheme")
public class MyUI extends UI {
   @Override
   protected void init(VaadinRequest vaadinRequest) {
      Label l1 = new Label("Your Name-\n",ContentMode.PREFORMATTED);
      Label l2 = new Label("Your Address-\n",ContentMode.PREFORMATTED);
      Label l3 = new Label("Your Postal code-\n",ContentMode.PREFORMATTED);
      final VerticalLayout vLayout = new VerticalLayout();
      final HorizontalLayout hLayout = new HorizontalLayout();
      vLayout.setDescription("This is a example of vertical layout");
      vLayout.addComponents(l1,l2,l3);;
      //hLayout.setDescription("This is example of Horizontal layout");
      // hLayout.addComponents(l1,l2,l3);
      setContent(vLayout);
      //setContent(hLayout);
   }
   @WebServlet(urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true)
   @VaadinServletConfiguration(ui = MyUI.class, productionMode = false)
   public static class MyUIServlet extends VaadinServlet {}
}

此程式碼將在瀏覽器中生成以下輸出。

當我們使用水平佈局而不是垂直佈局時，相同的程式碼將在瀏覽器中生成以下輸出。

網格

網格是 Vaadin 的另一個元件，使用者可以使用它在瀏覽器中表示表格資料。在本節中，我們將學習網格及其用法。

首先建立一個名為“Person”的類。

package com.TutorialsMy.myApp;

public class Person {
   private String name;
   private int number;
   public Person(){}
   public Person(String string, int i) {
      
      // TODO Auto-generated constructor stub
      this.name = string;
      this.number =i;
   }
   public String getName() {
      return name;
   }
   public void setName(String name) {
      this.name = name;
   }
   public int getNumber() {
      return number;
   }
   public void setNumber(int number) {
      this.number = number;
   }
}

現在，在 MyUI.java 類中新增以下程式碼：

package com.TutorialsMy.myApp;

import java.util.Arrays;
import java.util.List;
import javax.servlet.annotation.WebServlet;

import com.vaadin.annotations.Theme;
import com.vaadin.annotations.VaadinServletConfiguration;
import com.vaadin.server.VaadinRequest;
import com.vaadin.server.VaadinServlet;
import com.vaadin.shared.ui.ContentMode;

import com.vaadin.ui.Button;
import com.vaadin.ui.Grid;
import com.vaadin.ui.HorizontalLayout;
import com.vaadin.ui.Label;
import com.vaadin.ui.TextField;
import com.vaadin.ui.UI;
import com.vaadin.ui.VerticalLayout;

@Theme("mytheme")
public class MyUI extends UI {
   @Override
   protected void init(VaadinRequest vaadinRequest) {
      HorizontalLayout hLayout = new HorizontalLayout();
      
      // Have some data
      List<Person> people = Arrays.asList(
      new Person("First Boy", 98),
      new Person("Second Boy", 99),
      new Person("Thired Boy", 57));
      
      // Create a grid bound to the list
      Grid<Person> grid = new Grid<>();
      grid.setItems(people);
      grid.addColumn(Person::getName).setCaption("Name");
      grid.addColumn(Person::getNumber).setCaption("Number in Examination");
      hLayout.addComponent(grid);
      setContent(hLayout);
   }
   @WebServlet(urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true)
   @VaadinServletConfiguration(ui = MyUI.class, productionMode = false)
   public static class MyUIServlet extends VaadinServlet {}
}

完成這兩個步驟後，編譯並執行它們。您可以在瀏覽器中觀察以下輸出：

表單佈局

表單佈局是 Vaadin 的另一個元件，它幫助我們將資料以兩列格式表示。它看起來就像一個表單。在本節中，您將瞭解有關此佈局的更多資訊。

按如下所示編輯您的 MyUI.java 檔案：

package com.TutorialsMy.myApp;

import java.util.Arrays;
import java.util.List;
import javax.servlet.annotation.WebServlet;

import com.vaadin.annotations.Theme;
import com.vaadin.annotations.VaadinServletConfiguration;
import com.vaadin.icons.VaadinIcons;
import com.vaadin.server.UserError;
import com.vaadin.server.VaadinRequest;
import com.vaadin.server.VaadinServlet;
import com.vaadin.shared.ui.ContentMode;

import com.vaadin.ui.Button;
import com.vaadin.ui.FormLayout;
import com.vaadin.ui.Grid;
import com.vaadin.ui.HorizontalLayout;
import com.vaadin.ui.Label;
import com.vaadin.ui.TextField;
import com.vaadin.ui.UI;
import com.vaadin.ui.VerticalLayout;

@Theme("mytheme")
public class MyUI extends UI {
   
   @Override
   protected void init(VaadinRequest vaadinRequest) {
      FormLayout form = new FormLayout();
      TextField tf1 = new TextField("Name");
      tf1.setIcon(VaadinIcons.USER);
      tf1.setRequiredIndicatorVisible(true);
      form.addComponent(tf1);
      TextField tf2 = new TextField("Street address");
      tf2.setIcon(VaadinIcons.ROAD);
      form.addComponent(tf2);
      TextField tf3 = new TextField("Postal code");
      tf3.setIcon(VaadinIcons.ENVELOPE);
      form.addComponent(tf3);
      
      // normally comes from validation by Binder
      tf3.setComponentError(new UserError("Doh!"));
      setContent(form);
   }
   @WebServlet(urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true)
   @VaadinServletConfiguration(ui = MyUI.class, productionMode = false)
   public static class MyUIServlet extends VaadinServlet {}
}

編譯並執行上述程式碼後，它將在瀏覽器中呈現以下輸出：

面板

面板是一個帶有框架輪廓的單個元件容器。它為表單佈局提供了更多功能。在以下示例中，我們將瞭解如何在 Vaadin 中使用面板。

package com.TutorialsMy.myApp;

import java.util.Arrays;
import java.util.List;
import javax.servlet.annotation.WebServlet;

import com.vaadin.annotations.Theme;
import com.vaadin.annotations.VaadinServletConfiguration;
import com.vaadin.icons.VaadinIcons;
import com.vaadin.server.UserError;
import com.vaadin.server.VaadinRequest;
import com.vaadin.server.VaadinServlet;
import com.vaadin.shared.ui.ContentMode;

import com.vaadin.ui.Button;
import com.vaadin.ui.FormLayout;
import com.vaadin.ui.Grid;
import com.vaadin.ui.HorizontalLayout;
import com.vaadin.ui.Label;
import com.vaadin.ui.Panel;
import com.vaadin.ui.TextField;
import com.vaadin.ui.UI;
import com.vaadin.ui.VerticalLayout;

@Theme("mytheme")
public class MyUI extends UI {
   
   @Override
   protected void init(VaadinRequest vaadinRequest) {
      HorizontalLayout layout = new HorizontalLayout();
      Panel panel = new Panel("Panel Example ");
      panel.addStyleName("mypanelexample");
      panel.setSizeUndefined(); // Shrink to fit content
      layout.addComponent(panel);
      
      // Create the content
      FormLayout content = new FormLayout();
      content.addStyleName("mypanelcontent");
      content.addComponent(new TextField("Name"));
      content.addComponent(new TextField("Password"));
      content.setSizeUndefined(); // Shrink to fit
      content.setMargin(true);
      panel.setContent(content);
      setContent(panel);
   }
   @WebServlet(urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true)
   @VaadinServletConfiguration(ui = MyUI.class, productionMode = false)
   public static class MyUIServlet extends VaadinServlet {}
}

執行上述程式碼段後，它將在瀏覽器中生成以下輸出

子視窗

子視窗是活動瀏覽器內的浮動面板。這允許使用者將內容分割到不同的視窗中。與其他佈局元件一樣，它也由執行時 Vaadin Html 程式碼控制。在以下示例中，我們將看到子視窗面板的工作方式。

按如下所示更改您的 MYUI 程式碼。

package com.TutorialsMy.myApp;

import java.util.Arrays;
import java.util.List;
import javax.servlet.annotation.WebServlet;

import com.vaadin.annotations.Theme;
import com.vaadin.annotations.VaadinServletConfiguration;
import com.vaadin.icons.VaadinIcons;
import com.vaadin.server.UserError;
import com.vaadin.server.VaadinRequest;
import com.vaadin.server.VaadinServlet;
import com.vaadin.shared.ui.ContentMode;

import com.vaadin.ui.Button;
import com.vaadin.ui.FormLayout;
import com.vaadin.ui.Grid;
import com.vaadin.ui.HorizontalLayout;
import com.vaadin.ui.Label;
import com.vaadin.ui.Panel;
import com.vaadin.ui.TextField;
import com.vaadin.ui.UI;
import com.vaadin.ui.VerticalLayout;
import com.vaadin.ui.Window;

@Theme("mytheme")
public class MyUI extends UI {
   @Override
   protected void init(VaadinRequest vaadinRequest) {
      setContent(new Label("Sub Window"));

      // Create a sub-window and set the content
      Window subWindow = new Window("~~~~~~~~Sub-window Example~~~~~~~");
      VerticalLayout subContent = new VerticalLayout();
      subWindow.setContent(subContent);
      
      // Put some components in it
      subContent.addComponent(new Label("This is a new label inside the window"));
      subContent.addComponent(new Button("Click Me :)"));
      
      // Center it in the browser window
      subWindow.center();
      
      // Open it in the UI
      addWindow(subWindow);
   }
   @WebServlet(urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true)
   @VaadinServletConfiguration(ui = MyUI.class, productionMode = false)
   public static class MyUIServlet extends VaadinServlet {}
}

編譯並執行上述程式碼段後，您將在瀏覽器中獲得以下輸出。

選項卡頁

選項卡頁是一個多元件容器，允許使用選項卡在元件之間切換。所有選項卡都作為選項卡欄組織在選項卡頁的頂部。以下程式碼顯示瞭如何使用 Vaadin 選項卡頁。

請按如下所示修改您的 MyUI.java 類。

package com.TutorialsMy.myApp;

import java.util.Arrays;
import java.util.List;
import javax.servlet.annotation.WebServlet;import com.vaadin.annotations.Theme;

import com.vaadin.annotations.VaadinServletConfiguration;
import com.vaadin.icons.VaadinIcons;
import com.vaadin.server.UserError;
import com.vaadin.server.VaadinRequest;
import com.vaadin.server.VaadinServlet;
import com.vaadin.shared.ui.ContentMode;

import com.vaadin.ui.Button;
import com.vaadin.ui.FormLayout;
import com.vaadin.ui.Grid;
import com.vaadin.ui.HorizontalLayout;
import com.vaadin.ui.Label;
import com.vaadin.ui.Panel;
import com.vaadin.ui.TabSheet;
import com.vaadin.ui.TextField;
import com.vaadin.ui.UI;
import com.vaadin.ui.VerticalLayout;
import com.vaadin.ui.Window;

@Theme("mytheme")
public class MyUI extends UI {
   
   @Override
   protected void init(VaadinRequest vaadinRequest) {
      TabSheet tabsheet = new TabSheet();
      VerticalLayout layout = new VerticalLayout();
      layout.addComponent(tabsheet);
      
      // Create the first tab
      VerticalLayout tab1 = new VerticalLayout();
      tab1.addComponent(new Label("Eaxmple of Train"));
      tab1.setCaption("Train");
      tabsheet.addTab(tab1).setIcon(VaadinIcons.TRAIN);;
      
      // This tab gets its caption from the component caption
      VerticalLayout tab2 = new VerticalLayout();
      tab2.addComponent(new Label("Example of Plane"));
      tab2.setCaption("Plane");
      tabsheet.addTab(tab2).setIcon(VaadinIcons.AIRPLANE);
      setContent(layout);
   } 
   @WebServlet(urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true)
   @VaadinServletConfiguration(ui = MyUI.class, productionMode = false)
   public static class MyUIServlet extends VaadinServlet {}
}

執行上面給出的程式碼後，您可以在瀏覽器中觀察以下輸出。請注意，您可以根據您在選項卡標題中的選擇在火車和飛機之間切換。

絕對佈局

絕對佈局允許您以任意方式將內容放置在選擇位置。以下程式碼是絕對佈局用法的示例。

按如下所示更新 MyUI.java 類。

package com.TutorialsMy.myApp;

import java.util.Arrays;
import java.util.List;
import javax.servlet.annotation.WebServlet;

import com.vaadin.annotations.Theme;
import com.vaadin.annotations.VaadinServletConfiguration;
import com.vaadin.icons.VaadinIcons;
import com.vaadin.server.UserError;
import com.vaadin.server.VaadinRequest;
import com.vaadin.server.VaadinServlet;
import com.vaadin.shared.ui.ContentMode;

import com.vaadin.ui.AbsoluteLayout;
import com.vaadin.ui.Button;
import com.vaadin.ui.FormLayout;
import com.vaadin.ui.Grid;
import com.vaadin.ui.HorizontalLayout;
import com.vaadin.ui.Label;
import com.vaadin.ui.Panel;
import com.vaadin.ui.TabSheet;
import com.vaadin.ui.TextField;
import com.vaadin.ui.UI;
import com.vaadin.ui.VerticalLayout;
import com.vaadin.ui.Window;

@Theme("mytheme")
public class MyUI extends UI {
   
   @Override
   protected void init(VaadinRequest vaadinRequest) {
      
      // A 400x250 pixels size layout
      AbsoluteLayout layout = new AbsoluteLayout();
      layout.setWidth("400px");
      layout.setHeight("200px");
      
      // A component with coordinates for its top-left corner
      TextField text = new TextField("Example of Absolute Layout");
      layout.addComponent(text, "left: 50px; top: 50px;");
      setContent(layout);
   }
   @WebServlet(urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true)
   @VaadinServletConfiguration(ui = MyUI.class, productionMode = false)
   public static class MyUIServlet extends VaadinServlet {}
}

執行上述程式碼後，您可以在瀏覽器中觀察以下輸出：

自定義佈局

自定義佈局是可以根據您的需求自定義的佈局，因此得名。以下示例顯示瞭如何為我們的應用程式建立一個自定義佈局。

按如下所示更改 MyUI.java 類：

package com.TutorialsMy.myApp;

import java.util.Arrays;
import java.util.List;
import javax.servlet.annotation.WebServlet;

import com.vaadin.annotations.Theme;
import com.vaadin.annotations.VaadinServletConfiguration;
import com.vaadin.icons.VaadinIcons;
import com.vaadin.server.UserError;
import com.vaadin.server.VaadinRequest;
import com.vaadin.server.VaadinServlet;
import com.vaadin.shared.ui.ContentMode;

import com.vaadin.ui.AbsoluteLayout;
import com.vaadin.ui.Button;
import com.vaadin.ui.CustomLayout;
import com.vaadin.ui.FormLayout;
import com.vaadin.ui.Grid;
import com.vaadin.ui.HorizontalLayout;
import com.vaadin.ui.Label;
import com.vaadin.ui.Panel;
import com.vaadin.ui.TabSheet;
import com.vaadin.ui.TextField;
import com.vaadin.ui.UI;
import com.vaadin.ui.VerticalLayout;
import com.vaadin.ui.Window;

@Theme("mytheme")
public class MyUI extends UI {
   
   @Override
   protected void init(VaadinRequest vaadinRequest) {
      
      // A 400x250 pixels size layout
      Panel loginPanel = new Panel("Login");
      CustomLayout content = new CustomLayout("layoutname");
      content.setSizeUndefined();
      loginPanel.setContent(content);
      loginPanel.setSizeUndefined();
      
      // No captions for fields is they are provided in the template
      content.addComponent(new TextField(), "username");
      content.addComponent(new TextField(), "password");
      content.addComponent(new Button("Login"), "okbutton");
      
      //content.addComponent(loginPanel
      setContent(loginPanel);
      setContent(content);
   }
   @WebServlet(urlPatterns = "/*", name = "MyUIServlet", asyncSupported = true)
   @VaadinServletConfiguration(ui = MyUI.class, productionMode = false)
   public static class MyUIServlet extends VaadinServlet {}
}

執行上述程式碼段後，您可以在瀏覽器中觀察以下輸出：