用J2ME在移动设备上实现动画1_JSP教程

教程Tag：暂无Tag,欢迎添加,赚取U币!

推荐：用J2ME与ASP建立数据库连接
J2ME是利用HttpConnection建立HTTP连接，然后获取数据，ASP也是利用HTTP协议，因而可以利用J2ME与ASP建立连接，从而访问数据库。 ASP是MicroSoft公司的服务器端动态页面技术，可以根

使用MIDP(Mobile Information Device Profile)的开发人员经常会抱怨用些什么办法才可以在一个MIDlet上显示动画。 MIDP 1.0 没有直接提供对动画的支持(正在开发中的MIDP 2.0支持)，但真要是自己去实现，其实也并非是一件很难的事。

任何动画的最基本的前提，是要在足够快的时间内显示和更换一张张的图片，让人的眼睛看到动的画面效果。图片必须按照顺序画出来。从一张图片到下一张图片之间的变化越小，效果会越好。

首先要做的，是使用你的图片处理软件（比如ps或者firework）创建一系列相同大小的图片来组成动画。每张图片代表动画一帧。需要制作一定数量的祯－－越多的帧会让你的动画看上去越平滑。制作好的图片一定要保存成PNG(Portable Network Graphics)格式，MIDP唯一支持的图片格式；有两个办法让你刚做好的图片在MIDlet上变成动画。第一，把图片都放到一个web服务器上，让MIDlet下载他们，MIDP内置的HTTP支持。第二个办法更简单，把图片用MIDlet打包成jar文件。如果你使用的是J2ME开发工具，把PNG文件放入你的项目文件里面就可以了。

动画的过程其实更像帐本记录：显示当前帧，然后适当地更换到下一帧。那么使用一个类来完成这个工作应该是很恰当的，那好，我们就先定义一个AnimatedImage类：

import java.util.*;

import javax.microedition.lcdui.*;

// 定义了一个动画，该动画其实只是一系列相同大小的图片

// 轮流显示，然后模拟出的动画

public class AnimatedImage extends TimerTask {;

private Canvas canvas;

private Image[] images;

private int[][] clipList;

private int current;

private int x;

private int y;

private int w;

private int h;

// Construct an animation with no canvas.

public AnimatedImage( Image[] images ){;

this( null, images, null );

};

// Construct an animation with a null clip list.

public AnimatedImage( Canvas canvas, Image[]

images ){; this( canvas, images, null );

};

// Construct an animation. The canvas can be null,

// but if not null then a repaint will be triggered

// on it each time the image changes due to a timer

// event. If a clip list is specified, the image is

// drawn multiple times, each time with a different

// clip rectangle, to simulate transparent parts.

public AnimatedImage( Canvas canvas, Image[] images,

int[][] clipList ){;

this.canvas = canvas;

this.images = images;

this.clipList = clipList;

if( images != null && clipList != null ){;

if( clipList.length < images.length ){;

throw new IllegalArgumentException();

};

};

if( images != null && images.length > 0 ){;

w = images[0].getWidth();

h = images[0].getHeight();

};

};

// Move to the next frame, wrapping if necessary.

public void advance( boolean repaint ){;

if( current >= images.length ){;

current = 0;

};

if( repaint && canvas != null && canvas.isShown()

){;

canvas.repaint( x, y, w, h );

canvas.serviceRepaints();

};

};

// Draw the current image in the animation. If

// no clip list, just a simple copy, otherwise

// set the clipping rectangle accordingly and

// draw the image multiple times.

public void draw( Graphics g ){;

if( w == 0 || h == 0 ) return;

int which = current;

if( clipList == null || clipList[which] == null

){;

g.drawImage( images[which], x, y,

g.TOP | g.LEFT );

}; else {;

int cx = g.getClipX();

int cy = g.getClipY();

int cw = g.getClipWidth();

int ch = g.getClipHeight();

int[] list = clipList[which];

for( int i = 0; i 3 <= list.length; i =

4 ){;

g.setClip( x list[0], y list[1],

list[2], list[3] );

g.drawImage( images[which], x, y,

g.TOP | g.LEFT );

};

g.setClip( cx, cy, cw, ch );

};

};

// Moves the animation's top left corner.

public void move( int x, int y ){;

this.x = x;

this.y = y;

};

// Invoked by the timer. Advances to the next frame

// and causes a repaint if a canvas is specified.

public void run(){;

if( w == 0 || h == 0 ) return;

advance( true );

};

};

你实例化一个AnimatedImage对象的时候你必须给AnimatedImage类的构造方法传一个Image对象数组，该数组代表动画的每一帧。

// Construct an animation with no canvas.

public AnimatedImage( Image[] images ){;

this( null, images, null );

};

// Construct an animation with a null clip list.

public AnimatedImage( Canvas canvas, Image[]

images ){; this( canvas, images, null );

};

public AnimatedImage( Canvas canvas, Image[] images,

int[][] clipList ){;

this.canvas = canvas;

this.images = images;

this.clipList = clipList;

if( images != null && clipList != null ){;

if( clipList.length < images.length ){;

throw new IllegalArgumentException();

};

};

if( images != null && images.length > 0 ){;

w = images[0].getWidth();

h = images[0].getHeight();

};

};

// Move to the next frame, wrapping if necessary.

public void advance( boolean repaint ){;

if( current >= images.length ){;

current = 0;

};

if( repaint && canvas != null && canvas.isShown()

){;

canvas.repaint( x, y, w, h );

canvas.serviceRepaints();

};

};

// Draw the current image in the animation. If

// no clip list, just a simple copy, otherwise

// set the clipping rectangle accordingly and

// draw the image multiple times.

public void draw( Graphics g ){;

if( w == 0 || h == 0 ) return;

int which = current;

int[] list = clipList[which];

for( int i = 0; i 3 <= list.length; i =

4 ){;

g.setClip( x list[0], y list[1],

list[2], list[3] );

g.drawImage( images[which], x, y,

g.TOP | g.LEFT );

};

g.setClip( cx, cy, cw, ch );

};

};

// Moves the animation's top left corner.

public void move( int x, int y ){;

this.x = x;

this.y = y;

};

// Invoked by the timer. Advances to the next frame

// and causes a repaint if a canvas is specified.

public void run(){;

if( w == 0 || h == 0 ) return;

advance( true );

};

};

你实例化一个AnimatedImage对象的时候你必须给AnimatedImage类的构造方法传一个Image对象数组，该数组代表动画的每一帧。

// Construct an animation with no canvas.

public AnimatedImage( Image[] images ){;

this( null, images, null );

};

// Construct an animation with a null clip list.

public AnimatedImage( Canvas canvas, Image[]

images ){; this( canvas, images, null );

};

public AnimatedImage( Canvas canvas, Image[] images,

int[][] clipList ){;

this.canvas = canvas;

this.images = images;

this.clipList = clipList;

if( images != null && clipList != null ){;

if( clipList.length < images.length ){;

throw new IllegalArgumentException();

};

};

if( images != null && images.length > 0 ){;

w = images[0].getWidth();

h = images[0].getHeight();

};

};

// Move to the next frame, wrapping if necessary.

public void advance( boolean repaint ){;

if( current >= images.length ){;

current = 0;

};

if( repaint && canvas != null && canvas.isShown()

){;

canvas.repaint( x, y, w, h );

canvas.serviceRepaints();

};

};

// Draw the current image in the animation. If

// no clip list, just a simple copy, otherwise

// set the clipping rectangle accordingly and

// draw the image multiple times.

public void draw( Graphics g ){;

if( w == 0 || h == 0 ) return;

int which = current;

int[] list = clipList[which];

for( int i = 0; i 3 <= list.length; i =

4 ){;

g.setClip( x list[0], y list[1],

list[2], list[3] );

g.drawImage( images[which], x, y,

g.TOP | g.LEFT );

};

g.setClip( cx, cy, cw, ch );

};

};

// Moves the animation's top left corner.

public void move( int x, int y ){;

this.x = x;

this.y = y;

};

// Invoked by the timer. Advances to the next frame

// and causes a repaint if a canvas is specified.

public void run(){;

if( w == 0 || h == 0 ) return;

advance( true );

};

};

你实例化一个AnimatedImage对象的时候你必须给AnimatedImage类的构造方法传一个Image对象数组，该数组代表动画的每一帧。

分享：使用OTA来发布J2ME程序
众所周知，J2ME程序发布的形式主要有：OTA、数据线传输、红外和蓝牙传输等。这里简单说说如何通过OTA来发布你的程序。OTA是Over The Air的简写，也就是通过网络下载，这是主要的发布