j2me-ImageItem类

Java ME应用示例

最新推荐文章于 2019-12-02 11:33:32 发布

原创最新推荐文章于 2019-12-02 11:33:32 发布 · 385 阅读

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#user #getter #null #image #command #methods

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本文介绍了一个基于Java ME平台的应用示例，展示了如何创建并显示一个包含图片的基本界面，并实现退出功能。通过这个示例，读者可以了解Java ME应用程序的基本结构。

代码如下:

package hello;

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

public class HelloMIDlet extends MIDlet implements CommandListener{

privateboolean midletPaused = false;

   //<editor-fold defaultstate="collapsed" desc="Generated Fields ">
    privateCommand exitCommand;
    private Formform;
    privateImageItem imageItem;
    privateImage image1;
   //</editor-fold>

    publicHelloMIDlet() {
    }

//<editor-fold defaultstate="collapsed" desc="Generated Methods ">
//</editor-fold>

   //<editor-fold defaultstate="collapsed" desc="Generated Method: initialize ">

    private voidinitialize() {
       // write pre-initialize user code here

       // write post-initialize user code here
    }
   //</editor-fold>

   //<editor-fold defaultstate="collapsed" desc="Generated Method: startMIDlet ">

    public voidstartMIDlet() {
       // write pre-action user code here
       switchDisplayable(null, getForm());
       // write post-action user code here
    }
   //</editor-fold>

   //<editor-fold defaultstate="collapsed" desc="Generated Method: resumeMIDlet ">

    public voidresumeMIDlet() {
       // write pre-action user code here

       // write post-action user code here
    }
   //</editor-fold>

   //<editor-fold defaultstate="collapsed" desc="Generated Method: switchDisplayable ">

    public voidswitchDisplayable(Alert alert, Displayable nextDisplayable) {
       // write pre-switch user code here
       Display display = getDisplay();
       if (alert == null) {
           display.setCurrent(nextDisplayable);
       } else {
           display.setCurrent(alert, nextDisplayable);
       }
       // write post-switch user code here
    }
   //</editor-fold>

   //<editor-fold defaultstate="collapsed" desc="Generated Method: commandAction for Displayables">

    public voidcommandAction(Command command, Displayable displayable) {
       // write pre-action user code here
       if (displayable == form) {
           if (command == exitCommand) {
               // write pre-action user code here
               exitMIDlet();
               // write post-action user code here
           }
       }
       // write post-action user code here
    }
   //</editor-fold>

   //<editor-fold defaultstate="collapsed" desc="Generated Getter: exitCommand ">

    publicCommand getExitCommand() {
       if (exitCommand == null) {
           // write pre-init user code here
           exitCommand = new Command("Exit", Command.EXIT, 0);
           // write post-init user code here
       }
       return exitCommand;
    }
   //</editor-fold>

   //<editor-fold defaultstate="collapsed" desc="Generated Getter: form ">

    public FormgetForm() {
       if (form == null) {
           // write pre-init user code here
           form = new Form("Welcome", new Item[] { getImageItem() });
           form.addCommand(getExitCommand());
           form.setCommandListener(this);
           // write post-init user code here
       }
       return form;
    }
   //</editor-fold>

   //<editor-fold defaultstate="collapsed" desc="Generated Getter: imageItem ">

    public ImageItem getImageItem() {
       if (imageItem == null) {
           // write pre-init user code here
           imageItem = new ImageItem("imageItem", getImage1(),ImageItem.LAYOUT_DEFAULT,"</u7F3A/u5C11/u56FE/u50CF>");
           // write post-init user code here
       }
       return imageItem;
   }
   //</editor-fold>

   //<editor-fold defaultstate="collapsed" desc="Generated Getter: image1 ">

    public Image getImage1() {
       if (image1 == null) {
           // write pre-init user code here
           try {
               image1 = Image.createImage("/Snap1.jpg");
           } catch (java.io.IOException e) {
               Alert alert=new Alert("错误","找不到图像文件",null,null);
               alert.setTimeout(2000);
               alert.setType(AlertType.ERROR);
               switchDisplayable(alert,form);
           }
           // write post-init user code here
       }
       return image1;
   }
   //</editor-fold>

    publicDisplay getDisplay () {
       return Display.getDisplay(this);
    }

    public voidexitMIDlet() {
       switchDisplayable (null, null);
       destroyApp(true);
       notifyDestroyed();
    }

    public voidstartApp() {
       if (midletPaused) {
           resumeMIDlet ();
       } else {
           initialize ();
           startMIDlet ();
       }
       midletPaused = false;
    }

    public voidpauseApp() {
       midletPaused = true;
    }

    public voiddestroyApp(boolean unconditional) {
    }

}