Explosion.java

package com.dk.view.drop;

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; 
    public static final int STATE_DEAD = 1; 

    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;
        }
    }

    /**
     * When all particles are dead
     * The Explosition should be finished.
     * @param canvas
     * @return
     */
    public boolean draw(Canvas canvas) {
        boolean isAlive = false;
        for (int i = 0; i < this.particles.length; i++) {
            if (this.particles[i].isAlive()) {
                this.particles[i].draw(canvas);
                isAlive = true;
            }
        }
        return isAlive;
    }
  }