package com.particle; 
public class Particle { 
  int color; // 粒子颜色 
  int r; // 粒子半径 
  double vertical_v; // 垂直速度 
  double horizontal_v; // 水平速度 
  int startX; // 初始X坐标 
  int startY; // 初始Y坐标 
  int x; // 实时X坐标 
  int y; // 实时Y坐标 
  double startTime; // 起始时间 
  public Particle(int color, int r, double vertical_v, double horizontal_v, int x, int y, double startTime) { 
    super(); 
    this.color = color; 
    this.r = r; 
    this.vertical_v = vertical_v; 
    this.horizontal_v = horizontal_v; 
    this.startX = x; 
    this.startY = y; 
    this.x = x; 
    this.y = y; 
    this.startTime = startTime; 
  } 
}

package com.particle; 
import java.util.ArrayList; 
import android.graphics.Color; 
public class ParticleSet { 
  ArrayList<Particle> particleSet; 
  public ParticleSet() { 
    particleSet = new ArrayList<Particle>(); 
  } 
  /** 
   * 向粒子集合中添加指定数量的粒子对象 
   */ 
  public void add(int count, double startTime) { 
    for (int i = 0; i < count; i++) { 
      int tempColor = this.getColor(i); 
      int tempR = 1; // 粒子半径 
      double tempv_v = -30 + 10 * (Math.random()); // 随机产生粒子竖直方向的速度
      double tempv_h = 10 - 20 * (Math.random()); // 随机产生粒子水平方向的速度
      int tempX = 160; 
      int tempY = (int) (100 - 10 * (Math.random())); // 随机产生粒子Y坐标，90到100之间 
      Particle particle = new Particle(tempColor, tempR, tempv_v,
          tempv_h, tempX, tempY, startTime); 
      particleSet.add(particle); 
    } 
  } 
  /** 
   * 获取指定索引的颜色 
   */ 
  public int getColor(int i) { 
    int color = Color.RED; 
    switch (i%4) { 
    case 0: 
      color = Color.RED; 
      break; 
    case 1: 
      color = Color.GREEN; 
      break; 
    case 2: 
      color = Color.YELLOW; 
      break; 
    case 3: 
      color = Color.GRAY; 
      break; 
    } 
    return color; 
  } 
}

package com.particle; 
import java.util.ArrayList; 
public class ParticleThread extends Thread { 
  boolean flag; 
  ParticleView father; 
  int sleepSpan = 80; 
  double time = 0; // 物理引擎的时间轴 
  double span = 0.15; // 每次计算粒子位移时采用的时间间隔 
  public ParticleThread(ParticleView father) { 
    this.father = father; 
    this.flag = true; 
  } 
  @Override 
  public void run() { 
    while (flag) { 
      father.ps.add(5, time); // 每次添加5个粒子 
      ArrayList<Particle> tempSet = father.ps.particleSet; // 获取粒子集合 
      for (int i = tempSet.size() - 1; i >= 0; i--) { 
        Particle particle = tempSet.get(i); 
        double timeSpan = time - particle.startTime; // 计算从程序开始到现在经过的时间 
        int tempX = (int) (particle.startX + particle.horizontal_v * timeSpan); 
        int tempY = (int) (particle.startY + 4.9 * timeSpan * timeSpan + particle.vertical_v * timeSpan); 
        if (tempY > ParticleView.DIE_OUT_LINE) { // 如果粒子超过屏幕下边沿 
          tempSet.remove(particle); 
        } 
        particle.x = tempX; 
        particle.y = tempY; 
      } 
      time += span; 
      try { 
        Thread.sleep(sleepSpan); 
      } catch (Exception e) { 
        e.printStackTrace(); 
      } 
    } 
  } 
}

package com.particle; 
import java.util.ArrayList; 
import android.content.Context; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Paint; 
import android.graphics.RectF; 
import android.view.SurfaceHolder; 
import android.view.SurfaceHolder.Callback; 
import android.view.SurfaceView; 
public class ParticleView extends SurfaceView implements Callback { 
  public static final int DIE_OUT_LINE = 300; 
  DrawThread dt; 
  ParticleSet ps; 
  ParticleThread pt; 
  String fps = "FPS:N/A"; 
  public ParticleView(Context context) { 
    super(context); 
    this.getHolder().addCallback(this); 
    dt = new DrawThread(this, getHolder()); 
    ps = new ParticleSet(); 
    pt = new ParticleThread(this); 
  } 
  public void doDraw(Canvas canvas) { 
    canvas.drawColor(Color.BLACK); // 清屏 
    ArrayList<Particle> particleSet = ps.particleSet; 
    Paint paint = new Paint(); 
    for (int i = 0; i < particleSet.size(); i++) { 
      Particle p = particleSet.get(i); 
      paint.setColor(p.color); 
      int tempX = p.x; 
      int tempY = p.y; 
      int tempRadius = p.r; 
      RectF oval = new RectF(tempX, tempY, tempX + 2 * tempRadius, tempY 
          + 2 * tempRadius); 
      canvas.drawOval(oval, paint); // 绘制椭圆粒子 
    } 
    paint.setColor(Color.WHITE); 
    paint.setTextSize(18); 
    paint.setAntiAlias(true); 
    canvas.drawText(fps, 15, 15, paint); 
  } 
  @Override 
  public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) { 
  } 
  @Override 
  public void surfaceCreated(SurfaceHolder arg0) { 
    if (!dt.isAlive()) { 
      dt.start(); 
    } 
    if (!pt.isAlive()) { 
      pt.start(); 
    } 
  } 
  @Override 
  public void surfaceDestroyed(SurfaceHolder arg0) { 
    dt.flag = false; 
    dt = null; 
    pt.flag = false; 
    pt = null; 
  } 
}

package com.particle; 
import android.graphics.Canvas; 
import android.view.SurfaceHolder; 
public class DrawThread extends Thread { 
  ParticleView pv; 
  SurfaceHolder surfaceHolder; 
  boolean flag=false; 
  int sleepSpan=30; 
  long start =System.nanoTime(); //记录起始时间，该变量用于计算帧速率
  int count=0 ; //记录帧数 
  public DrawThread(ParticleView pv,SurfaceHolder surfaceHolder) { 
    this.pv=pv; 
    this.surfaceHolder=surfaceHolder; 
    this.flag=true; 
  } 
  public void run() { 
    Canvas canvas=null; 
    while(flag) { 
      try { 
        canvas=surfaceHolder.lockCanvas(null); //获取BallView的画布 
        synchronized (surfaceHolder) { 
          pv.doDraw(canvas); 
        } 
      } catch (Exception e) { 
        e.printStackTrace(); 
      } finally { 
        if(canvas!=null) { 
          surfaceHolder.unlockCanvasAndPost(canvas); // surfaceHolder解锁，并将画布传回 
        } 
      } 
      this.count++; 
      if(count==20) { //计满20帧时计算一次帧速率 
        count=0; 
        long tempStamp=System.nanoTime(); 
        long span=tempStamp-start; 
        start=tempStamp; 
        double fps=Math.round(100000000000.0/span*20)/100.0; 
        pv.fps="FPS:"+fps; 
      } 
      try { 
        Thread.sleep(sleepSpan); 
      } catch (InterruptedException e) { 
        e.printStackTrace(); 
      } 
    } 
  } 
}

package com.particle; 
import android.app.Activity; 
import android.os.Bundle; 
import android.view.Window; 
import android.view.WindowManager; 
public class MainActivity extends Activity { 
  ParticleView pv; 
  @Override 
  public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    requestWindowFeature(Window.FEATURE_NO_TITLE); //设置不显示标题 
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN); //设置全屏 
    pv=new ParticleView(this); 
    setContentView(pv); 
  } 
}

/** 
* 向粒子集合中添加指定数量的粒子对象（瀑布粒子效果） 
*/ 
public void add2(int count, double startTime) { 
    for (int i = 0; i < count; i++) { 
      int tempColor = this.getColor(i); 
      int tempR = 1; // 粒子半径 
      double tempv_v = 0; // 粒子竖直方向的速度为0 
      double tempv_h = 10 + 20 * (Math.random()); // 随机产生粒子水平方向的速度 
      int tempX = 50; 
      int tempY = (int) (50 - 10 * (Math.random())); // 随机产生粒子Y坐标，90到100之间 
      Particle particle = new Particle(tempColor, tempR, tempv_v,
          tempv_h, tempX, tempY, startTime); 
      particleSet.add(particle); 
    } 
}