Android实现粒子爆炸效果的方法

本文实例讲述了android实现粒子爆炸效果的方法。分享给大家供大家参考。具体如下：

1. explosion.java文件：

package net.obviam.particles.model;
import android.graphics.canvas;
import android.graphics.rect;
import android.util.log;
public class explosion {
  private static final string tag = explosion.class.getsimplename();
  public static final int state_alive   = 0;
  // at least 1 particle is alive
  public static final int state_dead   = 1;
  // all particles are dead
  private particle[] particles;
  // particles in the explosion
  private int x, y;
  // the explosion's origin
  private float gravity;
  // the gravity of the explosion (+ upward, - down)
  private float wind;
  // speed of wind on horizontal
  private int size; // number of particles
  private int state; // whether it's still active or not
  public explosion(int particlenr, int x, int y) {
    log.d(tag, "explosion created at " + x + "," + y);
    this.state = state_alive;
    this.particles = new particle[particlenr];
    for (int i = 0; i < this.particles.length; i++) {
      particle p = new particle(x, y);
      this.particles[i] = p;
    }
    this.size = particlenr;
  }
  public particle[] getparticles() {
    return particles;
  }
  public void setparticles(particle[] particles) {
    this.particles = particles;
  }
  public int getx() {
    return x;
  }
  public void setx(int x) {
    this.x = x;
  }
  public int gety() {
    return y;
  }
  public void sety(int y) {
    this.y = y;
  }
  public float getgravity() {
    return gravity;
  }
  public void setgravity(float gravity) {
    this.gravity = gravity;
  }
  public float getwind() {
    return wind;
  }
  public void setwind(float wind) {
    this.wind = wind;
  }
  public int getsize() {
    return size;
  }
  public void setsize(int size) {
    this.size = size;
  }
  public int getstate() {
    return state;
  }
  public void setstate(int state) {
    this.state = state;
  }
  // helper methods -------------------------
  public boolean isalive() {
    return this.state == state_alive;
  }
  public boolean isdead() {
    return this.state == state_dead;
  }
  public void update() {
    if (this.state != state_dead) {
      boolean isdead = true;
      for (int i = 0; i < this.particles.length; i++) {
        if (this.particles[i].isalive()) {
          this.particles[i].update();
          isdead = false;
        }
      }
      if (isdead)
        this.state = state_dead; 
    }
  }
  public void update(rect container) {
    if (this.state != state_dead) {
      boolean isdead = true;
      for (int i = 0; i < this.particles.length; i++) {
        if (this.particles[i].isalive()) {
          this.particles[i].update(container);
//         this.particles[i].update();
          isdead = false;
        }
      }
      if (isdead)
        this.state = state_dead; 
    }
  }
  public void draw(canvas canvas) {
    for(int i = 0; i < this.particles.length; i++) {
      if (this.particles[i].isalive()) {
        this.particles[i].draw(canvas);
      }
    }
  }
}

2. particle.java文件如下：

package net.obviam.particles.model;
import android.graphics.canvas;
import android.graphics.color;
import android.graphics.paint;
import android.graphics.rect;
public class particle {
  public static final int state_alive = 0;  // particle is alive
  public static final int state_dead = 1;   // particle is dead
  public static final int default_lifetime  = 200; // play with this
  public static final int max_dimension    = 5;  // the maximum width or height
  public static final int max_speed      = 10;  // maximum speed (per update)
  private int state;     // particle is alive or dead
  private float widht;    // width of the particle
  private float height;    // height of the particle
  private float x, y;     // horizontal and vertical position
  private double xv, yv;   // vertical and horizontal velocity
  private int age;      // current age of the particle
  private int lifetime;    // particle dies when it reaches this value
  private int color;     // the color of the particle
  private paint paint;    // internal use to avoid instantiation
  public int getstate() {
    return state;
  }
  public void setstate(int state) {
    this.state = state;
  }
  public float getwidht() {
    return widht;
  }
  public void setwidht(float widht) {
    this.widht = widht;
  }
  public float getheight() {
    return height;
  }
  public void setheight(float height) {
    this.height = height;
  }
  public float getx() {
    return x;
  }
  public void setx(float x) {
    this.x = x;
  }
  public float gety() {
    return y;
  }
  public void sety(float y) {
    this.y = y;
  }
  public double getxv() {
    return xv;
  }
  public void setxv(double xv) {
    this.xv = xv;
  }
  public double getyv() {
    return yv;
  }
  public void setyv(double yv) {
    this.yv = yv;
  }
  public int getage() {
    return age;
  }
  public void setage(int age) {
    this.age = age;
  }
  public int getlifetime() {
    return lifetime;
  }
  public void setlifetime(int lifetime) {
    this.lifetime = lifetime;
  }
  public int getcolor() {
    return color;
  }
  public void setcolor(int color) {
    this.color = color;
  }
  // helper methods -------------------------
  public boolean isalive() {
    return this.state == state_alive;
  }
  public boolean isdead() {
    return this.state == state_dead;
  }
  public particle(int x, int y) {
    this.x = x;
    this.y = y;
    this.state = particle.state_alive;
    this.widht = rndint(1, max_dimension);
    this.height = this.widht;
//   this.height = rnd(1, max_dimension);
    this.lifetime = default_lifetime;
    this.age = 0;
    this.xv = (rnddbl(0, max_speed * 2) - max_speed);
    this.yv = (rnddbl(0, max_speed * 2) - max_speed);
    // smoothing out the diagonal speed
    if (xv * xv + yv * yv > max_speed * max_speed) {
      xv *= 0.7;
      yv *= 0.7;
    }
    this.color = color.argb(255, rndint(0, 255), rndint(0, 255), rndint(0, 255));
    this.paint = new paint(this.color);
  }
  /**
   * resets the particle
   * @param x
   * @param y
   */
  public void reset(float x, float y) {
    this.state = particle.state_alive;
    this.x = x;
    this.y = y;
    this.age = 0;
  }
  // return an integer that ranges from min inclusive to max inclusive.
  static int rndint(int min, int max) {
    return (int) (min + math.random() * (max - min + 1));
  }
  static double rnddbl(double min, double max) {
    return min + (max - min) * math.random();
  }
  public void update() {
    if (this.state != state_dead) {
      this.x += this.xv;
      this.y += this.yv;
      // extract alpha
      int a = this.color >>> 24;
      a -= 2;               // fade by 5
      if (a <= 0) {            // if reached transparency kill the particle
        this.state = state_dead;
      } else {
        this.color = (this.color & 0x00ffffff) + (a << 24);    // set the new alpha
        this.paint.setalpha(a);
        this.age++;           // increase the age of the particle
//       this.widht *= 1.05;
//       this.height *= 1.05;
      }
      if (this.age >= this.lifetime) { // reached the end if its life
        this.state = state_dead;
      }
      // http://lab.polygonal.de/2007/05/10/bitwise-gems-fast-integer-math/
      //32bit
//     var color:uint = 0xff336699;
//     var a:uint = color >>> 24;
//     var r:uint = color >>> 16 & 0xff;
//     var g:uint = color >>> 8 & 0xff;
//     var b:uint = color & 0xff;
       
    }
  }
  public void update(rect container) {
    // update with collision
    if (this.isalive()) {
      if (this.x <= container.left || this.x >= container.right - this.widht) {
        this.xv *= -1;
      }
      // bottom is 480 and top is 0 !!!
      if (this.y <= container.top || this.y >= container.bottom - this.height) {
        this.yv *= -1;
      }
    }
    update();
  }
  public void draw(canvas canvas) {
//   paint.setargb(255, 128, 255, 50);
    paint.setcolor(this.color);
    canvas.drawrect(this.x, this.y, this.x + this.widht, this.y + this.height, paint);
//   canvas.drawcircle(x, y, widht, paint);
  }
}

希望本文所述对大家的android程序设计有所帮助。