Internship 8th day: SurfaceView shows animation effect (1)

By Surface

Original address: http://blog.csdn.net/ypist/article/details/8571032

1. Basic knowledge:

SurfaceView inherits from View. View is responsible for updating the animation in the main thread, while SurfaceView updates the animation in a new thread.

SurfaceView类的主要方法:
// 在SurfaceView创建时调用
pubilic abstract void surfaceCreated(SurfaceHolder holder)
// Call
pubilic abstract void surfaceChanged when SurfaceView changes strong>(SurfaceHolder holder, int format, int width, int height)
// Called when SurfaceView is destroyed
pubilic abstract voidsurfaceDestroyed (SurfaceHolder holder)
// Draw SurfaceView screen
protected void onDraw strong>(Canvas canvas)
(The parameter canvas is the brush of the SurfaceView, and this method is called every time the screen changes in the SurfaceView)

Second, achieve the effect: span>

First, a picture starts from the lower left corner of the screen and moves to the upper right. When the upper edge of the picture collides with the upper edge of the mobile phone screen, the horizontal speed and direction of the picture remain unchanged, and the vertical speed does not change.< br> The direction is opposite; after the bottom edge collides, the same effect will be applied until the picture flies off the screen. After that, the screen gradually displays a picture.

Three, programming realization:

1. Interface editing (res\layout\main.xml):

[java] view plain copy

  1. “1.0” encoding=“utf-8” ?>
  2. “http://schemas.android.com/apk/res/android”
  3. android:orientation=“vertical”
  4. android:layout_width=“fill_parent”< /span>
  5. android:layout_height=“fill_parent”
  8. android:layout_width=“fill_parent”
  9. android:layout_height=“wrap_content”
  10. android:text=“@string/hello”


2. Code editing:< /p>

(\src\wyf\zcl\MyActivity.Java)< /span>

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  1. packagewyf.zcl;
  2. /*
  3. * This example demonstrates the drawing of simple scenes in surfaceView
  4. * MyActivity.java is the main Activity of the program
  5. * MySurfaceView.java is the SurfaceView class of the program
  6. * Constant.java Constant class, write all constants in this class
  7. * OnDrawThread.java The function of this class is to refresh onDraw from time to time and redraw the screen
  8. * PicRunThread.java This class is control The class of duke picture movement
  9. **/
  10. import android.app.Activity; android.app.Activity; //Introduce related packages
  11. importandroid.content.pm.ActivityInfo; //Introduce related packages
  12. importandroid.os.Bundle; android.os.Bundle; //Introduce related packages
  13. import android.view.Window; android.view.Window; //Introducing related packages li>
  14. importandroid.view.WindowManager; //Introduce related packages

    15. < li class="alt" style="border-style:none none none solid; border-left-width:3px; border-left-color:rgb(108,226,108); list-style:decimal-leading-zero outside; color: inherit; line-height:18px; margin:0px!impo rtant; padding:0px 3px 0px 10px!important"> publicclass MyActivityextendsActivity{

  15. /** Called when the activity is first created.*/< /li>
  16. private< /span>MySurfaceView msv; msv;//Get a reference to surfaceView
  17. @Override< /span>
  18. publicvoidonCreate(BundlesavedInstanceState){ //Activity life cycle function, this function is called when the program is created< /span>
  19. super.onCreate(savedInstanceState);

    20. < li class="alt" style="border-style:none none none solid; border-left-width:3px; border-left-color:rgb(108,226,108); list-style:decimal-leading-zero outside; color: inherit; line-height:18px; margin:0px!important; padding:0px 3px 0px 10px!important"> msv=new MySurfaceView(MyActivity.this) ; //Instantiate the object of MySurfaceView

  20. requestWindowFeature(Window.FEATURE_NO_TITLE);//set screen display without title bar
  21. getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
  22. WindowManager.LayoutParams.FLAG_FULLSCREE ); //Set full screen
  23. //Set to allow horizontal screen only
  24. this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);  
  25.         setContentView(msv);                            //设置Activity显示的内容为msv  
  26.     }  
  27. }  


(\src\wyf\zcl\Constant.java)

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  1. package wyf.zcl;  
  2. import android.view.Display;  
  3. //Constant.java     常量类，将常量全部写在该类中  
  4. public class Constant {  
  5.     public static int SCREENWIDTH=480;  //屏幕宽（本程序为横屏）  
  6.     public static int SCREENHEIGHT=320;     //屏幕高  
  7.     public static int PICWIDTH=64;          //图片宽度  
  8.     public static int PICHEIGHT=64;         //图片高度  
  9.     public static int ONDRAWSPEED=30;       //onDraw线程类的绘制间隔时间  
  10.     public static float PICXSPEED=1.5f;     //图片水平移动速度  
  11.     public static float PICYSPEED=2;        //图片垂直移动速度  
  12.     public static int PICRUNSPEED=30;       //图片的运动线程的刷新速度  
  13.     public static int PICALPHASPEED=20; //图片渐暗效果演示刷新速度  
  14. }  


(\src\wyf\zcl\MySurfaceView.java)

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  1. package wyf.zcl;  
  2. import android.content.Context;                 //引入相关包  
  3. import android.graphics.Bitmap;                 //引入相关包  
  4. import android.graphics.BitmapFactory;          //引入相关包  
  5. import android.graphics.Canvas;                 //引入相关包  
  6. import android.graphics.Color;                  //引入相关包  
  7. import android.graphics.Paint;                  //引入相关包  
  8. import android.view.Display;                    //引入相关包  
  9. import android.view.SurfaceHolder;              //引入相关包  
  10. import android.view.SurfaceView;                //引入相关包  
  11. public class MySurfaceView extends SurfaceView  
  12. implements SurfaceHolder.Callback{            
  13.     //此处实现SurfaceHolder.Callback接口，为surfaceView添加生命周期回调函数  
  14.     int dy=Display.DEFAULT_DISPLAY;  
  15.     MyActivity ma;                          //得到MyActivity的引用  
  16.     Paint paint;                            //画笔的引用  
  17.     OnDrawThread odt;                       //OnDrawThread类引用  
  18.     PicRunThread prt;                       //图片运动的Thread类引用  
  19.     private float picX=0;                       //图片x坐标  
  20.     private float picY=0;                       //图片y坐标  
  21.     boolean picAlphaFlag=false;                 //图片变暗效果的标记，false为不显示，true为显示。   
  22.     int picAlphaNum=0;                          //图片变暗效果中画笔的alpha值  
  23.     public MySurfaceView(Context context) {  
  24.         super(context);  
  25.         this.ma=(MyActivity) context;             
  26.         //将ma的引用指向调用了该Surfaceview类构造器方法的对象，本例为MyActivity  
  27.         this.getHolder().addCallback(this);     //注册回调接口  
  28.         paint=new Paint();                      //实例化画笔  
  29.         odt=new OnDrawThread(this);             //实例化OnDrawThread类  
  30.         prt=new PicRunThread(this);             //实例化PicRunThread类  
  31.         prt.start();  
  32.     }  
  33.     public void setPicX(float picX) {           //图片x坐标的设置器  
  34.         this.picX = picX;  
  35.     }  
  36.     public void setPicY(float picY) {           //图片y坐标的设置器  
  37.         this.picY = picY;  
  38.     }  
  39.     public void setPicAlphaNum(int picAlphaNum) {//图片变暗效果alpha参数设置器  
  40.         this.picAlphaNum = picAlphaNum;  
  41.     }  
  42.     @Override  
  43.     protected void onDraw(Canvas canvas) {  //onDraw方法，此方法用于绘制图像，图形等  
  44.         super.onDraw(canvas);  
  45.         paint.setColor(Color.WHITE);        //设置画笔为白色  
  46.         canvas.drawRect(0, 0, Constant.SCRE ENWIDTH, Constant.SCREENHEIGHT, paint);  
  47.         //此处画了一个白色的全屏幕的矩形，目的是设置背景为白色，同时每次重绘时清除背景  
  48.         //进行平面贴图  
  49.         Bitmap bitmapDuke=BitmapFactory.decodeResource(ma.getResources(), R.drawable.duke);  
  50.         canvas.drawBitmap(bitmapDuke, picX, picY, paint);  
  51.         //图片渐暗效果  
  52.         if(picAlphaFlag){  
  53.             Bitmap bitmapBG=BitmapFactory.decodeResource(ma.getResources(), R.drawable.jpg1);  
  54.             paint.setAlpha(picAlphaNum);  
  55.             canvas.drawBitmap(bitmapBG, 0,0, paint);  
  56.         }  
  57.     }  
  58.     @Override  
  59.     public void surfaceChanged(SurfaceHolder holder, int format, int width,  
  60.             int height) {           //此方法为当surfaceView改变时调用，如屏幕大小改变。   
  61.     }  
  62.     @Override  
  63.     public void surfaceCreated(SurfaceHolder holder) {//此方法为在surfaceView创建时调用  
  64.         odt.start();                //启动onDraw的绘制线程  
  65.     }  
  66.     @Override  
  67.     public void surfaceDestroyed(SurfaceHolder holder) {//此方法为在surfaceView销毁前调用  
  68.     }  
  69. }  


(\src\wyf\zcl\OnDrawThread.java)

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  1. package wyf.zcl;  
  2. import android.graphics.Canvas;                 //引入相关包  
  3. import android.view.SurfaceHolder;              //引入相关包  
  4. //该类的作用是时时刷新onDraw，进行画面的重绘  
  5. public class OnDrawThread extends Thread{  
  6.     MySurfaceView msv;      //得到MySurfaceView的引用  
  7.     SurfaceHolder sh;       //SurfaceHolder引用  
  8.     public OnDrawThread(MySurfaceView msv) {  
  9.         super();  
  10.         this.msv = msv;         //构造方法中，将msv引用指向调用了该类的MySurfaceView的对象  
  11.         sh=msv.getHolder();  
  12.     }  
  13.     @Override  
  14.     public void run() {  
  15.         super.run();  
  16.         Canvas canvas = null;   //Canvas的引用  
  17.         while(true){  
  18.             try{  
  19.                 canvas=sh.lockCanvas(null);         //将canvas的引用指向surfaceView的canvas的对象  
  20.                 synchronized(this. sh){              //绘制过程，可能带来同步方面的问题，加锁  
  21.                     if(canvas!=null< /span>){  
  22.                     msv.onDraw(canvas);  
  23.                     }  
  24.                 }  
  25.             }finally{  
  26.                 try{  
  27.                         if(sh!=null){  
  28.                             sh.unlockCanvasAndPost(canvas); //绘制完后解锁  
  29.                         }  
  30.                 }catch(Exception e){e.printStackTrace();}  
  31.             }  
  32.             try{  
  33.                 Thread.sleep(Constant.ONDRAWSPEED);                 //休息1秒钟  
  34.             }catch(Exception e){e.printStackTrace();}  
  35.         }  
  36.     }  
  37. }  


(\src\wyf\zcl\PicRunThread.java)

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  1. package wyf.zcl;  
  2. //该类是控制duke图片运动的类  
  3. public class PicRunThread extends T hread{  
  4.     MySurfaceView msv;                                  //MySurfaceView的引用  
  5.     private float picX=0;           //图片x坐标  
  6.     private float picY=Constant.SCREENHEIGHT-Constant.PICHEIGHT;            //图片y坐标  
  7.     boolean yRunFlag=false;     //y方向上的运动标记，false时y=y+speed，true时y=y-sp eed  
  8.     int picAlphaNum=0;                  //图片变暗效果中画笔的alpha值  
  9.     public PicRunThread(MySurfaceView msv) {  
  10.         super();  
  11.         this.msv = msv;         //将该线程类的引用指向调用其的MySurfaceView的对象  
  12.     }  
  13.     @Override  
  14.     public void run() {  
  15.         super.run();  
  16.         while(true){  
  17.             //控制duke图片的运动  
  18.             while(this.picX//当图片的左边完全超过屏幕的右边时，循环结束  
  19.                 msv.setPicX(picX);  
  20.                 msv.setPicY(picY);  
  21.                 picX=picX+Constant.PICXSPEED;  
  22.                 if(yRunFlag){//应该向上运动，自减  
  23.                     picY=picY-Constant.PICYSPEED;  
  24.                 }else{//应该向下运动，自加  
  25.                     picY=picY+Constant.PICYSPEED;  
  26.                 }  
  27.                 if(picY<=0){                                 //到达屏幕上沿  
  28.                     yRunFlag=false;  
  29.                 }else if(picY>Constant.SCREENHEIGHT-Constant.PICHEIGHT){     //到达屏幕下沿  
  30.                     yRunFlag=true;  
  31.                 }  
  32.                 try{  
  33.                     Thread.sleep(Constant.PICRUNSPEED);  
  34.                 }catch(Exception e){e.printStackTrace();}  
  35.             }  
  36.             //图片变暗效果演示  
  37.             msv.picAlphaFlag=true;                          //开启图片变暗效果  
  38.             for(picAlphaNum=0;picAlphaNum<=255;picAlphaNum++){  
  39.                 if (picAlphaNum==255){  
  40.                     msv.picAlphaFlag=false;                 //当图片变暗效果结束，标记重置  
  41.                     picX=0;         //图片x坐标  
  42.                     picY=Constant.SCREENHEIGHT-Constant.PICHEIGHT;          //图片y坐标  
  43.                     System.out.println(msv.picAlphaFlag+“picX:”+picX+“picY:”+picY);  
  44.                 }  
  45.                 msv.setPicAlphaNum(picAlphaNum);  
  46.                 try{  
  47.                     Thread.sleep(Constant.PICALPHASPEED);  
  48.                 }catch(Exception e){e.printStackTrace();}  
  49.             }  
  50.         }  
  51.     }  
  52. }  


这部分代码对于我这个初学java的人来说比较吃力，但是硬着头皮看了两天，还是基本弄清了这个框架。

代码中涉及一些java的基础知识，我做了一点笔记，如下：


[ extends ]:

一个类使用关键字extends继承其他类，关键字extends出现在类声明时的类名后，
extends后面跟着的是要继承的类的名称，extends实现了继承。在Java中的类只能继承一个类。

[ super ]:

B 继承 A ，B想调用A的方法，那么就可以 用super.A的方法。如果用中文解释：super就是父类的一个别名。


[ implements ]:

implements是一个类实现一个接口用的关键字，
他是用来实现接口中定义的抽象方法
。比如：people是一个接口，他里面有say这个方法。
public interface people()
{
   public say();
}
但是接口没有方法体。
只能通过一个具体的类去实现其中的方法体。
比如chinese这个类，就实现了people这个接口。
 public class chinese implements peopel{ 
   public say()
   {System.out.println(“你好！”);}
}


[ e xtends和implements区别]:

[plain]  view plain  copy

  1. extends是继承父类，只要那个类不是声明为final或者那个类定义为abstract的就能继承，  
  2. JAVA中不支持多重继承，但是可以用接口来实现，这样就要用到implements，继承只能继承一个类，  
  3. 但implements可以实现多个接口，用逗号分开就行了   
  4. 比如   
  5. class A extends B implements C,D,E  

[java]  view plain  copy

  1. “1.0” encoding=“utf-8”?>  
  2. “http://schemas.android.com/apk/res/android”  
  3.     android:orientation=“vertical”  
  4.     android:layout_width=“fill_parent”  
  5.     android:layout_height=“fill_parent”  
  6.     >  
  8.     android:layout_width=“fill_parent”   
  9.     android:layout_height=“wrap_content”   
  10.     android:text=“@string/hello”  
  11.     />  
  12.   

[java]  view plain  cop y

[java]  view plain  copy

[java]  view plain  copy

  1. package wyf.zcl;  
  2. /* 
  3.  *  该例子演示surfaceView中简单场景的绘制 
  4.  *  MyActivity.java     为程序的主Activity 
  5.  *  MySurfaceView.java  为程序的SurfaceView类 
  6.  *  Constant.java       常量类，将常量全部写在该类中 
  7.  *  OnDrawThread.java   该类的作用是时时刷新onDraw，进行画面的重绘 
  8.  *  PicRunThread.java   该类是控制duke图片运动的类 
  9.  * */  
  10. import android.app.Activity;                        //引入相关包  
  11. import android.content.pm.ActivityInfo;             //引入相关包  
  12. import android.os.Bundle;                           //引入相关包  
  13. import android.view.Window;                         //引入相关包  
  14. import android.view.WindowManager;                  //引入相关包   
  15. public class MyActivity extends Activity {  
  16.     /** Called when the activity is first created. */  
  17.     private MySurfaceView msv;          //得到surfaceView的引用  
  18.     @Override  
  19.     public void onCreate(Bundle savedInstanceState) {   //Activity的生命周期函数，该函数是在程序创建时调用  
  20.         super.onCreate(savedInstanceState);  
  21.         msv=new MySurfaceView(MyActivity.this);         //实例化MySurfaceView的对象  
  22.         requestWindowFeature(Window.FEATURE_NO_TITLE);  //设置屏幕显示没有title栏   
  23.         getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN ,    
  24.                       WindowManager.LayoutParams.FLAG_FULLSCREEN);  //设置全屏  
  25.         //设置只允许横屏  
  26.         this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);  
  27.         setContentView(msv);                            //设置Activity显示的内容为msv  
  28.     }  
  29. }  

[java]  view plain  copy

[java]  view plain  copy

[java]  view plain  copy

  1. package wyf.zcl;  
  2. import android.view.Display;  
  3. //Constant.java     常量类，将常量全部写在该类中  
  4. public class Constant {  
  5.     public static int SCREENWIDTH=480;  //屏幕宽（本程序为横屏）  
  6.     public static int SCREENHEIGHT=320;     //屏幕高  
  7.     public static int PICWIDTH=64;          //图片宽度  
  8.     public static int PICHEIGHT=64;         //图片高度  
  9.     public static int ONDRAWSPEED=30;       //onDraw线程类的绘制间隔时间  
  10.     public static float PICXSPEED=1.5f;     //图片水平移动速度  
  11.     public static float PICYSPEED=2;        //图片垂直移动速度  
  12.     public static int PICRUNSPEED=30;       //图片的运动线程的刷新速度  
  13.     public static int PICALPHASPEED=20; //图片渐暗效果演示刷新速度  
  14. }  

[java]  view plain  copy

[java]  view plain  copy

[java]  view plain  copy

  1. package wyf.zcl;  
  2. import android.content.Context;                 //引入相关包  
  3. import android.graphics.Bitmap;                 //引入相关包  
  4. import android.graphics.BitmapFactory;          //引入相关包  
  5. import android.graphics.Canvas;                 //引入相关包  
  6. import android.graphics.Color;                  //引入相关包  
  7. import android.graphics.Paint;                  //引入相关包  
  8. import android.view.Display;                    //引入相关包  
  9. import android.view.SurfaceHolder;              //引入相关包  
  10. import android.view.SurfaceView;                //引入相关包  
  11. public class MySurfaceView extends SurfaceView  
  12. implements SurfaceHolder.Callback{            
  13.     //此处实现SurfaceHolder.Callback接口，为surfaceView添加生命周期回调函数  
  14.     int dy=Display.DEFAULT_DISPLAY;  
  15.     MyActivity ma;                          //得到MyActivity的引用  
  16.     Paint paint;                            //画笔的引用  
  17.     OnDrawThread odt;                       //OnDrawThread类引用  
  18.     PicRunThread prt;                       //图片运动的Thread类引用  
  19.     private float picX=0;                       //图片x坐标  
  20.     private float picY=0;                       //图片y坐标  
  21.     boolean picAlphaFlag=false;                 //图片变暗效果的标记，false为不显示，true为显示。   
  22.     int picAlphaNum=0;                          //图片变暗效果中画笔的alpha值  
  23.     public MySurfaceView(Context context) {  
  24.         super(context);  
  25.         this.ma=(MyActivity) context;             
  26.         //将ma的引用指向调用了该Surfaceview类构造器方法的对象，本例为MyActivity  
  27.         this.getHolder().addCallback(this);     //注册回调接口  
  28.         paint=new Paint();                      //实例化画笔  
  29.         odt=new OnDrawThread(this);             //实例化OnDrawThread类  
  30.         prt=< span class="keyword" style="margin:0px; padding:0px; border:none; color:rgb(0,102,153); font-weight:bold; background-color:inherit">new PicRunThread(this);             //实例化PicRunThread类  
  31.         prt.start();  
  32.     }  
  33.     public void setPicX(float picX) {           //图片x坐标的设置器  
  34.         this.picX = picX;  
  35.     }  
  36.     public void setPicY(float picY) {           //图片y坐标的设置器  
  37.         this.picY = picY;  
  38.     }  
  39.     public void setPicAlphaNum(int picAlphaNum) {//图片变暗效果alpha参数设置器  
  40.         this.picAlphaNum = picAlphaNum;  
  41.     }  
  42.     @Override  
  43.     protected void onDraw(Canvas canvas) {  //onDraw方法，此方法用于绘制图像，图形等  
  44.         super.onDraw(canvas);  
  45.         paint.setColor(Color.WHITE);        //设置画笔为白色  
  46.         canvas.drawRect(0, 0, Constant.SCREENWIDTH, Constant.SCREENH EIGHT, paint);  
  47.         //此处画了一个白色的全屏幕的矩形，目的是设置背景为白色，同时每次重绘时清除背景  
  48.         //进行平面贴图  
  49.         Bitmap bitmapDuke=BitmapFactory.decodeResource(ma.getResources(), R.drawable.duke);  
  50.         canvas.drawBitmap(bitmapDuke, picX, picY, paint);  
  51.         //图片渐暗效果  
  52.         if(picAlphaFlag){  
  53.             Bitmap bitmapBG=BitmapFactory.decodeResource(ma.getResources(), R.drawable.jpg1);  
  54.             paint.setAlpha(picAlphaNum);  
  55.             canvas.drawBitmap(bitmapBG, 0,0, paint);  
  56.         }  
  57.     }  
  58.     @Override  
  59.     public void surfaceChanged(SurfaceHolder holder, int format, int width,  
  60.             int height) {           //此方法为当surfaceView改变时调用，如屏幕大小改变。   
  61.     }  
  62.     @Override  
  63.     public void surfaceCreated(SurfaceHolder holder) {//此方法为在surfaceView创建时调用  
  64.         odt.start();                //启动onDraw的绘制线程  
  65.     }  
  66.     @Override  
  67.     public void surfaceDestroyed(SurfaceHolder holder) {//此方法为在surfaceView销毁前调用  
  68.     }  
  69. }  

[java]  view plain  copy

[java]  view plain  copy

[java]  view plain  copy

  1. package wyf.zcl;  
  2. import android.graphics.Canvas;                 //引入相关包  
  3. import android.view.SurfaceHolder;              //引入相关包  
  4. //该类的作用是时时刷新onDraw，进行画面的重绘  
  5. public class OnDrawThread extends Thread{  
  6.     MySurfaceView msv;      //得到MySurfaceView的引用  
  7.     SurfaceHolder sh;       //SurfaceHolder引用  
  8.     public OnDrawThread(MySurfaceView msv) {  
  9.         super();  
  10.         this.msv = msv;         //构造方法中，将msv引用指向调用了该类的MySurfaceView的对象  
  11.         sh=msv.getHolder();  
  12.     }  
  13.     @Override  
  14.     public void run() {  
  15.         super.run();  
  16.         Canvas canvas = null;   //Canvas的引用  
  17.         while(true){  
  18.             try{  
  19.                 canvas=sh.lockCanvas(null);         //将canvas的引用指向surfaceView的canvas的对象  
  20.                 synchronized(this.sh){              //绘制过程，可能带来同步方面的问题，加锁  
  21.                     if(canvas!=null){  
  22.                     msv.onDraw(canvas);  
  23.                     }  
  24.                 }  
  25.             }finally{  
  26.                 try{  
  27.                         if(sh!=null){  
  28.                             sh.unlockCanvasAndPost(canvas); //绘制完后解锁  
  29.                         }  
  30.                 }catch(Exception e){e.printStackTrace();}  
  31.             }  
  32.             try{  
  33.                 Thread.sleep(Constant.ONDRAWSPEED);                 //休息1秒钟  
  34.             }catch(Exception e){e.printStackTrace();}  
  35.         }  
  36.     }  
  37. }  

[java]  view plain  copy

[java]  view plain  copy

[java]  view plain  copy

  1. package wyf.zcl;  
  2. //该类是控制duke图片运动的类  
  3. public class PicRunThread extends Thread{  
  4.     MySurfaceView msv;                                  //MySurfaceView的引用  
  5.     private float picX=0;           //图片x坐标  
  6.     private float picY=Constant.SCREENHEIGHT-Constant.PICHEIGHT;            //图片y坐标  
  7.     boolean yRunFlag=false;     //y方向上的运动标记，false时y=y+speed，true时y=y-speed  
  8.     int picAlphaNum=0;                  //图片变暗效果中画笔的alpha值  
  9.     public PicRunThread(MySurfaceView msv) {  
  10.         super();  
  11.         this.msv = msv;         //将该线程类的引用指向调用其的MySurfaceView的对象  
  12.     }  
  13.     @Override  
  14.     public void run() {  
  15.         super.run();  
  16.         while(true){  
  17.             //控制duke图片的运动  
  18.             while(this.picX//当图片的左边完全超过屏幕的右边时，循环结束  
  19.                 msv.setPicX(picX);  
  20.                 msv.setPicY(picY);  
  21.                 picX=picX+Constant. PICXSPEED;  
  22.                 if(yRunFlag){//应该向上运动，自减  
  23.                     picY=picY-Constant.PICYSPEED;  
  24.                 }else{//应该向下运动，自加  
  25.                     picY=picY+Constant.PICYSPEED;  
  26.                 }  
  27.                 if(picY<=0){                                 //到达屏幕上沿  
  28.                     yRunFlag=false;  
  29.                 }else if(picY>Constant.SCREENHEIGHT-Constant.PICHEIGHT){     //到达屏幕下沿  
  30.                     yRunFlag=true;  
  31.                 }  
  32.                 try{  
  33.                     Thread.sleep(Constant.PICRUNSPEED);  
  34.                 }catch(Exception e){e.printStackTrace();}  
  35.             }  
  36.             //图片变暗效果演示  
  37.             msv.picAlphaFlag=true;                          //开启图片变暗效果  
  38.             for(picAlphaNum=0;picAlphaNum<=255;picAlphaNum++){  
  39.                 if(picAlphaNum==255){  
  40.                     msv.picAlphaFlag=false;                 //当图片变暗效果结束，标记重置  
  41.                     picX=0;         //图片x坐标  
  42.                     picY=Constant.SCREENHEIGHT-Constant.PICHEIGHT;          //图片y坐标  
  43.                     System.out.println(msv.picAlphaFlag+“picX:”+picX+“picY:”+picY);  
  44.                 }  
  45.                 msv.setPicAlphaNum(picAlphaNum);  
  46.                 try{  
  47.                     Thread.sleep(Constant.PICALPHASPEED);  
  48.                 }catch(Exception e){e.printStackTrace();}  
  49.             }  
  50.         }  
  51.     }  
  52. }  

[java]  view plain  copy

[java]  view plain  copy

[plain]  view plain  copy

  1. extends是继承父类，只要那个类不是声明为final或者那个类定义为abstract的就能继承，  
  2. JAVA中不支持多重继承，但是可以用接口来实现，这样就要用到implements，继承只能继承一个类，  
  3. 但implements可以实现多个接口，用逗号分开就行了   
  4. 比如   
  5. class A extends B implements C,D,E  

[plain]  view plain  copy

[plain]  view plain  copy

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