在eventHandler中显示GWT DialogBox

import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.DialogBox;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.VerticalPanel;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;

public class MyDialogBox extends DialogBox {
  public MyDialogBox() {
    // 设置对话框标题
    setText("My Dialog Box");

    // 创建垂直面板
    VerticalPanel panel = new VerticalPanel();

    // 添加文本和按钮
    Label label = new Label("This is a dialog box.");
    Button closeButton = new Button("Close");
    closeButton.addClickHandler(new ClickHandler() {
      public void onClick(ClickEvent event) {
        // 关闭对话框
        hide();
      }
    });

    // 将组件添加到面板中
    panel.add(label);
    panel.add(closeButton);

    // 将面板添加到对话框中
    setWidget(panel);
  }
}

import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.user.client.ui.Button;

public class MyButton extends Button {
  public MyButton() {
    setText("Show Dialog Box");

    addClickHandler(new ClickHandler() {
      public void onClick(ClickEvent event) {
        // 创建对话框实例
        MyDialogBox dialogBox = new MyDialogBox();

        // 显示对话框
        dialogBox.show();
      }
    });
  }
}