最近需要完成这样的一个效果：
sdasd.gif
看上去就是动画跟贝塞尔曲线的组合，但是因为动画不熟悉，所以比较难以实现，这里的代码是摘取至 hcc大神的分享
LoveLikeLayout：
public class LoveLikeLayout extends RelativeLayout {
//线性插值器
private Interpolator line = new LinearInterpolator();
//加速插值器
private Interpolator acc = new AccelerateInterpolator();
//减速插值器
private Interpolator dce = new DecelerateInterpolator();
//先加速后减速插值器
private Interpolator accdec = new AccelerateDecelerateInterpolator();
//插值器数组
private Interpolator[] interpolators;
//随机数
private Random mRandom = new Random();
//爱心图片数组
private Drawable[] drawables;
//爱心图片的高度
private int drawableHeight;
//爱心图片的宽度
private int drawableWidth;
//参数值
private LayoutParams layoutParams;
//layout高度
private int measuredHeight;
//layout宽度
private int measuredWidth;
public LoveLikeLayout(Context context) {
this(context, null);
}
public LoveLikeLayout(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public LoveLikeLayout(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
/**
* 初始化
*/
private void init() {
//初始化爱心图片
drawables = new Drawable[3];
Drawable red = getResources().getDrawable(R.drawable.pl_red);
Drawable yellow = getResources().getDrawable(R.drawable.pl_yellow);
Drawable blue = getResources().getDrawable(R.drawable.pl_blue);
drawables[0] = red;
drawables[1] = yellow;
drawables[2] = blue;
//获取爱心的宽高
drawableHeight = red.getIntrinsicHeight();
drawableWidth = red.getIntrinsicWidth();
//设置爱心的显示位置
layoutParams = new LayoutParams(drawableWidth, drawableHeight);
layoutParams.addRule(CENTER_HORIZONTAL, TRUE);
layoutParams.addRule(ALIGN_PARENT_BOTTOM, TRUE);
//初始化动画插值器
interpolators = new Interpolator[4];
interpolators[0] = line;
interpolators[1] = acc;
interpolators[2] = dce;
interpolators[3] = accdec;
}
/**
* 测量layout的宽高
* 用于计算爱心的显示位置
*
* @param widthMeasureSpec
* @param heightMeasureSpec
*/
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
measuredHeight = getMeasuredHeight();
measuredWidth = getMeasuredWidth();
}
/**
* 显示爱心
*/
public void addLove() {
final ImageView imageView = new ImageView(getContext());
//随机生成爱心颜色
imageView.setImageDrawable(drawables[mRandom.nextInt(3)]);
imageView.setLayoutParams(layoutParams);
addView(imageView);
Animator animtor = getAnimtor(imageView);
animtor.addListener(new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
removeView(imageView);
super.onAnimationEnd(animation);
}
});
animtor.start();
}
/**
* 爱心的显示和运行轨迹动画组合实现
*
* @param target
* @return
*/
private Animator getAnimtor(View target) {
AnimatorSet enterAnimtorSet = getEnterAnimtorSet(target);
ValueAnimator bezierAnimtor = getBezierAnimtor(target);
AnimatorSet animatorSet = new AnimatorSet();
animatorSet.playSequentially(enterAnimtorSet);
animatorSet.playSequentially(enterAnimtorSet, bezierAnimtor);
animatorSet.setInterpolator(interpolators[mRandom.nextInt(4)]);
animatorSet.setTarget(target);
return animatorSet;
}
/**
* 爱心的显示动画实现
*
* @param target
* @return
*/
private AnimatorSet getEnterAnimtorSet(View target) {
//爱心的3中动画组合 透明度 x，y轴的缩放
ObjectAnimator alpha = ObjectAnimator.ofFloat(target, View.ALPHA, 0.2f, 1f);
ObjectAnimator scaleX = ObjectAnimator.ofFloat(target, View.SCALE_X, 0.2f, 1f);
ObjectAnimator scaleY = ObjectAnimator.ofFloat(target, View.SCALE_Y, 0.2f, 1f);
//组合动画
AnimatorSet set = new AnimatorSet();
set.setDuration(500);
set.setInterpolator(new LinearInterpolator());
set.playTogether(alpha, scaleX, scaleY);
set.setTarget(target);
return set;
}
/**
* 爱心运动轨迹的动画实现
*
* @param target
* @return
*/
private ValueAnimator getBezierAnimtor(final View target) {
BezierEvaluator evaluator = new BezierEvaluator(getPoint(2), getPoint(1));
ValueAnimator animator = ValueAnimator.ofObject(evaluator,
new PointF((measuredWidth - drawableWidth) / 2, measuredHeight - drawableHeight),
new PointF(mRandom.nextInt(getWidth()), 0));
animator.setDuration(3000);
animator.setTarget(target);
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator valueAnimator) {
//获取贝塞尔曲线的运动轨迹 让爱心跟随着移动
PointF animatedValue = (PointF) valueAnimator.getAnimatedValue();
target.setX(animatedValue.x);
target.setY(animatedValue.y);
//增加透明度的变化
target.setAlpha(1 - valueAnimator.getAnimatedFraction());
}
});
return animator;
}
/**
* 获取中间的两个点
*
* @return
*/
private PointF getPoint(int scale) {
PointF pointF = new PointF();
pointF.x = mRandom.nextInt((measuredWidth - 100));
pointF.y = mRandom.nextInt((measuredHeight - 100)) / scale;
return pointF;
}
}
BezierEvaluator：
public class BezierEvaluator implements TypeEvaluator {
private PointF pointF1;
private PointF pointF2;
public BezierEvaluator(PointF pointF1, PointF pointF2) {
this.pointF1 = pointF1;
this.pointF2 = pointF2;
}
@Override
public PointF evaluate(float time, PointF startValue, PointF endValue) {
float timeLeft = 1.0f - time;
PointF point = new PointF();//结果
point.x = timeLeft * timeLeft * timeLeft * (startValue.x)
+ 3 * timeLeft * timeLeft * time * (pointF1.x)
+ 3 * timeLeft * time * time * (pointF2.x)
+ time * time * time * (endValue.x);
point.y = timeLeft * timeLeft * timeLeft * (startValue.y)
+ 3 * timeLeft * timeLeft * time * (pointF1.y)
+ 3 * timeLeft * time * time * (pointF2.y)
+ time * time * time * (endValue.y);
return point;
}
}
用法：
public class LoveActivity extends AppCompatActivity {
private LoveLikeLayout mLoveLikeLayout;
private Button btn;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_love);
mLoveLikeLayout = (LoveLikeLayout) findViewById(R.id.id_LoveLikeLayout);
btn = (Button) findViewById(R.id.btn);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mLoveLikeLayout.addLove();
}
});
}
先把代码摘录下来，后面再研究。。