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();
        }
    }
}