android 路径动画制作

1、前言

             今天项目要用到一个类似微信发送么么哒，那种屏幕飘表情的功能，所以分析研究了一下，用到的技术应该是路径动画，不知道这样就正不正确，反正就是画一个路径线，然后对象根据这个路径去运动。所以就叫他路径动画了。

路径动画要首先要解决的问题就是怎么画这个路径？然后路径画出来后怎么取路径上的所有点的坐标值？

       这里解决这两个问题就看一个类PathMeasure 这个类接收一个path对象，然后可以根据pathMeasure.getPosTan（）可以得到长度比例的坐标值。这两个问题就直接搞定了。用path画一个路径然后取点，动态移动对象，就变成了路径动画了。是不是很简单。

2、看效果

3、核心代码

 /**
  * 撒花
  *
  * @author yd
  *

  用到的知识点：
     1、android属性动画
     2、Path路径绘制
     3、贝塞尔曲线
  *
  *
  *
  *
  *
  *
  *
  *
  */
 public class FllowerAnimation extends View implements AnimatorUpdateListener {

     /**
      * 动画改变的属性值
      */
     private float phase1 = 0f;
     private float phase2 = 0f;
     private float phase3 = 0f;

     /**
      * 小球集合
      */
     private List fllowers1 = new ArrayList();
     private List fllowers2 = new ArrayList();
     private List fllowers3 = new ArrayList();

     /**
      * 动画播放的时间
      */
     private int time = 4000;
     /**
      * 动画间隔
      */
     private int delay = 500;

     /**
      * 资源ID
      */
 //  private int resId = R.drawable.fllower_love;

     public FllowerAnimation(Context context) {
         super(context);
         init(context);
 //      this.resId = resId;
     }

     @SuppressWarnings("deprecation")
     private void init(Context context) {
         WindowManager wm = (WindowManager) context
                 .getSystemService(Context.WINDOW_SERVICE);
         width = wm.getDefaultDisplay().getWidth();
         height = (int) (wm.getDefaultDisplay().getHeight() * 3 / 2f);

         mPaint = new Paint();
         mPaint.setAntiAlias(true);
         mPaint.setStrokeWidth(2);
         mPaint.setColor(Color.BLUE);
         mPaint.setStyle(Style.STROKE);

         pathMeasure = new PathMeasure();

         builderFollower(fllowerCount, fllowers1);
         builderFollower(fllowerCount , fllowers2);
         builderFollower(fllowerCount , fllowers3);

     }

     /**
      * 宽度
      */
     private int width = 0;
     /**
      * 高度
      */
     private int height = 0;

     /**
      * 曲线高度个数分割
      */
     private int quadCount = 10;
     /**
      * 曲度
      */
     private float intensity = 0.2f;

     /**
      * 第一批个数
      */
     private int fllowerCount = 4;

     /**
      * 创建花
      */
     private void builderFollower(int count, List fllowers) {

         int max = (int) (width * 3 / 4f);
         int min = (int) (width / 4f);
         Random random = new Random();
         for (int i = 0; i < count; i++) {
             int s = random.nextInt(max) % (max - min + 1) + min;
             Path path = new Path();
             CPoint CPoint = new CPoint(s, 0);
             List points = builderPath(CPoint);
             drawFllowerPath(path, points);
             Fllower fllower = new Fllower();
             fllower.setPath(path);
             fllowers.add(fllower);
         }

     }

     /**
      * 画曲线
      * @param path
      * @param points
      */
     private void drawFllowerPath(Path path, List points) {
         if (points.size() > 1) {
             for (int j = 0; j < points.size(); j++) {

                 CPoint point = points.get(j);

                 if (j == 0) {
                     CPoint next = points.get(j + 1);
                     point.dx = ((next.x - point.x) * intensity);
                     point.dy = ((next.y - point.y) * intensity);
                 } else if (j == points.size() - 1) {
                     CPoint prev = points.get(j - 1);
                     point.dx = ((point.x - prev.x) * intensity);
                     point.dy = ((point.y - prev.y) * intensity);
                 } else {
                     CPoint next = points.get(j + 1);
                     CPoint prev = points.get(j - 1);
                     point.dx = ((next.x - prev.x) * intensity);
                     point.dy = ((next.y - prev.y) * intensity);
                 }

                 // create the cubic-spline path
                 if (j == 0) {
                     path.moveTo(point.x, point.y);
                 } else {
                     CPoint prev = points.get(j - 1);
                     path.cubicTo(prev.x + prev.dx, (prev.y + prev.dy),
                             point.x - point.dx, (point.y - point.dy),
                             point.x, point.y);
                 }
             }
         }
     }

     /**
      * 曲线摇摆的幅度
      */
     private int range = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 70, getResources().getDisplayMetrics());

     /**
      * 画路径
      *
      * @param point
      * @return
      */
     private List builderPath(CPoint point) {
         List points = new ArrayList();
         Random random = new Random();
         for (int i = 0; i < quadCount; i++) {
             if (i == 0) {
                 points.add(point);
             } else {
                 CPoint tmp = new CPoint(0, 0);
                 if (random.nextInt(100) % 2 == 0) {
                     tmp.x = point.x + random.nextInt(range);
                 } else {
                     tmp.x = point.x - random.nextInt(range);
                 }
                 tmp.y = (int) (height / (float) quadCount * i);
                 points.add(tmp);
             }
         }
         return points;
     }

     /**
      * 画笔
      */
     private Paint mPaint;

     /**
      * 测量路径的坐标位置
      */
     private PathMeasure pathMeasure = null;

     @Override
     protected void onDraw(Canvas canvas) {
         super.onDraw(canvas);

         drawFllower(canvas, fllowers1);
         drawFllower(canvas, fllowers2);
         drawFllower(canvas, fllowers3);

     }

     /**
      * 高度往上偏移量,把开始点移出屏幕顶部
      */
     private float dy = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,40, getResources().getDisplayMetrics());

     /**
      *
      * @param canvas
      * @param fllowers
      */
     private void drawFllower(Canvas canvas, List fllowers) {
         for (Fllower fllower : fllowers) {
             float[] pos = new float[2];
             canvas.drawPath(fllower.getPath(),mPaint);
             pathMeasure.setPath(fllower.getPath(), false);
             pathMeasure.getPosTan(height * fllower.getValue(), pos, null);
             canvas.drawCircle(pos[0], pos[1], 10, mPaint);
 //          Bitmap bitmap = BitmapFactory.decodeResource(getResources(), resId);
 //          canvas.drawBitmap(bitmap, pos[0], pos[1] - dy, null);
 //          bitmap.recycle();
         }
     }

     public void startAnimation() {
         ObjectAnimator mAnimator1 = ObjectAnimator.ofFloat(this, "phase1", 0f,
                 1f);
         mAnimator1.setDuration(time);
         mAnimator1.addUpdateListener(this);
         mAnimator1.start();
         mAnimator1.setInterpolator(new AccelerateInterpolator(1f));

         ObjectAnimator mAnimator2 = ObjectAnimator.ofFloat(this, "phase2", 0f,
                 1f);
         mAnimator2.setDuration(time);
         mAnimator2.addUpdateListener(this);
         mAnimator2.start();
         mAnimator2.setInterpolator(new AccelerateInterpolator(1f));
         mAnimator2.setStartDelay(delay);

         ObjectAnimator mAnimator3 = ObjectAnimator.ofFloat(this, "phase3", 0f,
                 1f);
         mAnimator3.setDuration(time);
         mAnimator3.addUpdateListener(this);
         mAnimator3.start();
         mAnimator3.setInterpolator(new AccelerateInterpolator(1f));
         mAnimator3.setStartDelay(delay * 2);
     }

     /**
      * 跟新小球的位置
      *
      * @param value
      * @param fllowers
      */
     private void updateValue(float value, List fllowers) {
         for (Fllower fllower : fllowers) {
             fllower.setValue(value);
         }
     }

     /**
      * 动画改变回调
      */
     @Override
     public void onAnimationUpdate(ValueAnimator arg0) {

         updateValue(getPhase1(), fllowers1);
         updateValue(getPhase2(), fllowers2);
         updateValue(getPhase3(), fllowers3);
         Log.i(tag, getPhase1() + "");
         invalidate();
     }

     public float getPhase1() {
         return phase1;
     }

     public void setPhase1(float phase1) {
         this.phase1 = phase1;
     }

     public float getPhase2() {
         return phase2;
     }

     public void setPhase2(float phase2) {
         this.phase2 = phase2;
     }

     public float getPhase3() {
         return phase3;
     }

     public void setPhase3(float phase3) {
         this.phase3 = phase3;
     }

     private String tag = this.getClass().getSimpleName();

     private class CPoint {

         public float x = 0f;
         public float y = 0f;

         /** x-axis distance */
         public float dx = 0f;

         /** y-axis distance */
         public float dy = 0f;

         public CPoint(float x, float y) {
             this.x = x;
             this.y = y;
         }
     }

 }

4、项目地址

http://download.csdn.net/detail/hxc2008q/8473053

转自：http://blog.csdn.net/spring_he/article/details/44064607