LWUIT显示漂亮的loading界面的两种方法

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原文出处：http://blog.csdn.net/pjw100/archive/2009/11/23/4854740.aspx

 

 

我们加载某一个Form页面时，如果这个页面内容较多，加载需要一定的时间，那我们就希望做一个等待的画面，比如"某某正在加载,请等 待..."，在这个画面中以动态效果来说为最好，用户也知道需要等待很短的时间。我做等待界面有两种方法：

首先是方法一，这种方法属于文字等待，就是在界面上画一串文字，"..."是以动态的形式显示，代码如下：

 /*
  * To change this template, choose Tools | Templates
  * and open the template in the editor.
  */
 package  com.thinkrace.icredit;
 import  com.sun.lwuit.Font;
 import  com.sun.lwuit.Form;
 import  com.sun.lwuit.Graphics;
 import  com.sun.lwuit.Image;
 import  com.sun.lwuit.Label;
 import  com.sun.lwuit.layouts.BorderLayout;
 import  java.io.IOException;
 import  java.util.Random;
 import  java.util.Timer;
 import  java.util.TimerTask;
 /**
  *
  * @author Administrator
  */
 public   class  SplashForm  extends  Form  implements  Runnable {
     private  Timer timer =  new  Timer();
     private   long  displayTime =  1000 ;
     private  StringBuffer loading =  new  StringBuffer( "Saleslion is loading" );
     public  SplashForm() {
         Thread t = new  Thread( this );
         t.start();
         this .setLayout( new  BorderLayout());
         this .show();
     }
     public   void  paint(Graphics g) {
         try  {
             Image wait = Image.createImage("/logo.png" );
             //绘制logo
             g.drawImage(wait, (getWidth() - wait.getWidth()) / 2 , (getHeight() - wait.getHeight()-  70 ) /  2 );
             g.setColor(0xffffff );
             Font fnt = Font.createSystemFont(Font.FACE_PROPORTIONAL, Font.STYLE_PLAIN, Font.SIZE_LARGE);
             g.setFont(fnt);
             int  wordWidth = fnt.stringWidth( "Saleslion is loading..." );
             //绘制等待字符串
             g.drawString(loading.toString(), (getWidth() - wordWidth) / 2 , (getHeight() + wait.getHeight() - 60 ) /  2 );
         } catch  (IOException ex) {
             ex.printStackTrace();
         }
     }
     private   void  disappear() {
         timer.cancel();
         try  {
             new  LoginForm();
         } catch  (IOException ex) {
             ex.printStackTrace();
         }
     }
     //调用TimerTask，时间到了后，调用 disappear()，当前画面消失，跳至另一个Form
     protected   void  showNotify() {
         timer.schedule(new  TimerTask() {
             public   void  run() {
                 disappear();
             }
         }, displayTime);
     }
     //设置字符串
     public   void  setLoading() {
         if  (loading.toString().indexOf( "..." ) >  0 ) {
             loading.delete(loading.length() - 3 , loading.length());
         }
     }
     public   void  run() {
         while  ( true ) {
             try  {
                 //调用线程来绘制字符串
                 Thread.sleep(500 );
                 setLoading();
                 loading.append("." );
             } catch  (Exception e) {
             }
             repaint();
         }
     }
 }

/* * To change this template, choose Tools | Templates * and open the template in the editor. */ package com.thinkrace.icredit; import com.sun.lwuit.Font; import com.sun.lwuit.Form; import com.sun.lwuit.Graphics; import com.sun.lwuit.Image; import com.sun.lwuit.Label; import com.sun.lwuit.layouts.BorderLayout; import java.io.IOException; import java.util.Random; import java.util.Timer; import java.util.TimerTask; /** * * @author Administrator */ public class SplashForm extends Form implements Runnable { private Timer timer = new Timer(); private long displayTime = 1000; private StringBuffer loading = new StringBuffer("Saleslion is loading"); public SplashForm() { Thread t = new Thread(this); t.start(); this.setLayout(new BorderLayout()); this.show(); } public void paint(Graphics g) { try { Image wait = Image.createImage("/logo.png"); //绘制logo g.drawImage(wait, (getWidth() - wait.getWidth()) / 2, (getHeight() - wait.getHeight()- 70) / 2); g.setColor(0xffffff); Font fnt = Font.createSystemFont(Font.FACE_PROPORTIONAL, Font.STYLE_PLAIN, Font.SIZE_LARGE); g.setFont(fnt); int wordWidth = fnt.stringWidth("Saleslion is loading..."); //绘制等待字符串 g.drawString(loading.toString(), (getWidth() - wordWidth) / 2, (getHeight() + wait.getHeight() -60) / 2); } catch (IOException ex) { ex.printStackTrace(); } } private void disappear() { timer.cancel(); try { new LoginForm(); } catch (IOException ex) { ex.printStackTrace(); } } //调用TimerTask，时间到了后，调用disappear()，当前画面消失，跳至另一个Form protected void showNotify() { timer.schedule(new TimerTask() { public void run() { disappear(); } }, displayTime); } //设置字符串 public void setLoading() { if (loading.toString().indexOf("...") > 0) { loading.delete(loading.length() - 3, loading.length()); } } public void run() { while (true) { try { //调用线程来绘制字符串 Thread.sleep(500); setLoading(); loading.append("."); } catch (Exception e) { } repaint(); } } }

以上代码比较简单，也不做多的解释，它是基于Form的。

但是这并不是我想要的效果，假如在一个九宫格中，我点击某一格时，我希望出现一个loading画面显示正在加载这一项，但是以遮罩的形式显示（就 像web开发里面弹出的遮罩层对话框一样），也就是说，弹出loading时，我仍然能够见到原来的九宫格画面。我要的效果如下图：

如果要实现这种形式的loading画面，只有通过Dialog类来实现。

制作这种Dialog有几个小问题需要解决：

1.lwuit中如何显示gif动画

2.Dialog全透明

3.Dialog自动释放

一直没有实现这个效果，关键是问题1，但是在上一节 我已经解决了，下面就看关键代码，代码仍然很简单：

 /*
  * To change this template, choose Tools | Templates
  * and open the template in the editor.
  */
 package  com.thinkrace.UCHome.ui;
 import  com.sun.lwuit.Dialog;
 import  com.sun.lwuit.Display;
 import  com.sun.lwuit.Image;
 import  com.sun.lwuit.Label;
 import  com.sun.lwuit.util.Resources;
 import  java.io.IOException;
 /**
  *
  * @author Administrator
  */
 public   class  LoadingDialog  extends  Dialog {
     public  LoadingDialog() {
         try  {
             //设置对话框全透明
             for  ( int  i =  0 ; i < getComponentCount(); i++) {
                 getComponentAt(i).getStyle().setBgTransparency(0 );
             }
             Image icon = Resources.open("/resources.res" ).getImage( "loading.gif" );
             Label l = new  Label(icon);
             l.getStyle().setBgTransparency(0 );
             addComponent(l);
             int  w = Display.getInstance().getDisplayWidth();
             int  h = Display.getInstance().getDisplayHeight();
             int  top = (h - icon.getHeight()) /  2  -  10 ;
             int  left = (w - icon.getWidth()) /  2  -  10 ;

             setTimeout(3000 );
             show(top,top,left,left,false );

         } catch  (IOException ex) {
             ex.printStackTrace();
         }
     }
 }