rotateimagemidlet.java

Java ME手机应用开发大全一书的配套光盘上的源码

import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
import java.io.*;
import javax.microedition.lcdui.game.Sprite;
public class RotateImageMIDlet extends MIDlet {
  //声明Display对象
  Display display;
  Image image = null;
  public void startApp() {
	Display display = Display.getDisplay(this);
    //通过外部图像文件创建Image对象
	try{
	  image = Image.createImage("/10.png");
	}
	catch(Exception e){
	}
    //实例化画布屏幕
    Displayable d = new RotateImageCanvas(image);
    display.setCurrent(d);
  }

  public void pauseApp() {}

  public void destroyApp(boolean unconditional) {}
 
  class RotateImageCanvas extends Canvas implements CommandListener{

     int width = 0;
     int height = 0;
     Image image = null;
     private Command exitCommand;
	 //声明是否翻转图像的标志位
     boolean rotate=false;
   RotateImageCanvas(Image image){
	  this.image = image;
	  exitCommand = new Command("翻转", Command.SCREEN, 1);
	  addCommand(exitCommand);
      setCommandListener(this);
  }
  public void paint(Graphics g) {
	//获取屏幕的高度和宽度
    width  = getWidth();
    height = getHeight();
	//填充屏幕
    g.setGrayScale(255);
	g.fillRect(0,0,width-1,height-1);
	g.setGrayScale(0);
    g.drawRect(0,0,width-1,height-1);
	if(rotate)
    //翻转图像270度
	g.drawRegion(image,0,0,image.getWidth(),image.getHeight(),Sprite.TRANS_ROT270,width/2,height/2,g.TOP|g.HCENTER);
	else
	//正常显示图像
    g.drawImage(image,width/2,height/2,g.HCENTER|g.VCENTER);	     
  }
 public void commandAction(Command c, Displayable s) {
	     //点击翻转按钮，设置翻转标志位为true，调用paint()方法
         rotate=true;
		 repaint();   

  }
}
}