@Override
protected void onDraw(Canvas canvas) {
for (int i = 0; i < balls.size(); ++i) {
ShapeHolder shapeHolder = balls.get(i);
canvas.save();
canvas.translate(shapeHolder.getX(), shapeHolder.getY());
shapeHolder.getShape().draw(canvas);
canvas.restore();
}
}
private ShapeHolder addBall(float x, float y) {
OvalShape circle = new OvalShape();
circle.resize(50f, 50f);
ShapeDrawable drawable = new ShapeDrawable(circle);
ShapeHolder shapeHolder = new ShapeHolder(drawable);
shapeHolder.setX(x - 25f);
shapeHolder.setY(y - 25f);
int red = (int) (Math.random() * 255);
int green = (int) (Math.random() * 255);
int blue = (int) (Math.random() * 255);
int color = 0xff000000 | red << 16 | green << 8 | blue;
Paint paint = drawable.getPaint(); // new Paint(Paint.ANTI_ALIAS_FLAG);
int darkColor = 0xff000000 | red / 4 << 16 | green / 4 << 8 | blue / 4;
RadialGradient gradient =
new RadialGradient(37.5f, 12.5f, 50f, color, darkColor, Shader.TileMode.CLAMP);
paint.setShader(gradient);
shapeHolder.setPaint(paint);
balls.add(shapeHolder);
return shapeHolder;
}
@Override
public boolean onTouchEvent(MotionEvent event) {
if (event.getAction() != MotionEvent.ACTION_DOWN
&& event.getAction() != MotionEvent.ACTION_MOVE) {
return false;
}
ShapeHolder newBall = addBall(event.getX(), event.getY());
// Bouncing animation with squash and stretch
float startY = newBall.getY();
float endY = getHeight() - 50f;
float h = (float) getHeight();
float eventY = event.getY();
int duration = (int) (500 * ((h - eventY) / h));
ValueAnimator bounceAnim = ObjectAnimator.ofFloat(newBall, "y", startY, endY);
bounceAnim.setDuration(duration);
bounceAnim.setInterpolator(new AccelerateInterpolator());
ValueAnimator squashAnim1 =
ObjectAnimator.ofFloat(newBall, "x", newBall.getX(), newBall.getX() - 25f);
squashAnim1.setDuration(duration / 4);
squashAnim1.setRepeatCount(1);
squashAnim1.setRepeatMode(ValueAnimator.REVERSE);
squashAnim1.setInterpolator(new DecelerateInterpolator());
ValueAnimator squashAnim2 =
ObjectAnimator.ofFloat(newBall, "width", newBall.getWidth(), newBall.getWidth() + 50);
squashAnim2.setDuration(duration / 4);
squashAnim2.setRepeatCount(1);
squashAnim2.setRepeatMode(ValueAnimator.REVERSE);
squashAnim2.setInterpolator(new DecelerateInterpolator());
ValueAnimator stretchAnim1 = ObjectAnimator.ofFloat(newBall, "y", endY, endY + 25f);
stretchAnim1.setDuration(duration / 4);
stretchAnim1.setRepeatCount(1);
stretchAnim1.setInterpolator(new DecelerateInterpolator());
stretchAnim1.setRepeatMode(ValueAnimator.REVERSE);
ValueAnimator stretchAnim2 =
ObjectAnimator.ofFloat(newBall, "height", newBall.getHeight(), newBall.getHeight() - 25);
stretchAnim2.setDuration(duration / 4);
stretchAnim2.setRepeatCount(1);
stretchAnim2.setInterpolator(new DecelerateInterpolator());
stretchAnim2.setRepeatMode(ValueAnimator.REVERSE);
ValueAnimator bounceBackAnim = ObjectAnimator.ofFloat(newBall, "y", endY, startY);
bounceBackAnim.setDuration(duration);
bounceBackAnim.setInterpolator(new DecelerateInterpolator());
// Sequence the down/squash&stretch/up animations
AnimatorSet bouncer = new AnimatorSet();
bouncer.play(bounceAnim).before(squashAnim1);
bouncer.play(squashAnim1).with(squashAnim2);
bouncer.play(squashAnim1).with(stretchAnim1);
bouncer.play(squashAnim1).with(stretchAnim2);
bouncer.play(bounceBackAnim).after(stretchAnim2);
// Fading animation - remove the ball when the animation is done
ValueAnimator fadeAnim = ObjectAnimator.ofFloat(newBall, "alpha", 1f, 0f);
fadeAnim.setDuration(250);
fadeAnim.addListener(
new AnimatorListenerAdapter() {
@Override
public void onAnimationEnd(Animator animation) {
balls.remove(((ObjectAnimator) animation).getTarget());
}
});
// Sequence the two animations to play one after the other
AnimatorSet animatorSet = new AnimatorSet();
animatorSet.play(bouncer).before(fadeAnim);
// Start the animation
animatorSet.start();
return true;
}
