1、前言
今天项目要用到1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1下，用到的技术应当是路径动画，不知道这样就正不正确，反正就是画1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样画这个路径？然后路径画出来后怎样取路径上的所有点的坐标值？
这里解决这两个问题就看1个类PathMeasure 这个类接收1个path对象，然后可以根据pathMeasure.getPosTan（）可以得到长度比例的坐标值。这两个问题就直接弄定了。用path画1个路径然后取点，动态移动对象，就变成了路径动画了。是否是很简单。
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<fllower> fllowers1 = new ArrayList<fllower>();
private List<fllower> fllowers2 = new ArrayList<fllower>();
private List<fllower> fllowers3 = new ArrayList<fllower>();
/**
* 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<fllower> 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<cpoint> 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<cpoint> 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<cpoint> builderPath(CPoint point) {
List<cpoint> points = new ArrayList<cpoint>();
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<fllower> 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<fllower> 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;
}
}
}
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