android objectanimator 卡顿,android那些事--属性动画05-ObjectAnimator的高级使用

最新推荐文章于 2024-08-11 03:42:31 发布

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最新推荐文章于 2024-08-11 03:42:31 发布

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文章标签： android objectanimator 卡顿

本文详细介绍了如何在Android中使用ObjectAnimator进行自定义属性动画，结合TypeEvaluator实现小球移动并改变颜色的效果。通过示例代码展示了如何创建动画并避免性能卡顿，包括PointEvaluator和ColorEvaluator的使用。

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如果看了objectanimator(真正的劳动者)和TypeEvaluator的使用那么你对自定义TypeEvaluator和对任意属性做动画这两个概念就应该很熟悉了.下面这个例子就是对二者的综合使用.

我们知道补间动画的效果很局限于移动,缩放,旋转,和淡入淡出这四种效果.通过ObjectAnimator我们可以完成对任意属性设置动画效果,通过TypeEvaluator我们可以改变动画的效果显示状态.

需求:移动小球,并改变小球颜色.

blic class MyView extends View {

private Paint mPaint;

private Point mPoint;

private String color;

public String getColor() {

return color;

}

public void setColor(String color) {

this.color = color;

mPaint.setColor(Color.parseColor(color));

invalidate();

}

public MyView(Context context) {

super(context);

init();

}

public MyView(Context context, AttributeSet attrs) {

super(context, attrs);

init();

}

public MyView(Context context, AttributeSet attrs, int defStyleAttr) {

super(context, attrs, defStyleAttr);

init();

}

private void init() {

mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);

mPaint.setColor(Color.BLUE);

}

@Override

protected void onDraw(Canvas canvas) {

super.onDraw(canvas);

if (mPoint == null) {

mPoint = new Point(50, 50);

drawCircle(canvas);

startAnimation();

} else {

drawCircle(canvas);

}

private void drawCircle(Canvas canvas) {

canvas.drawCircle(mPoint.getX(), mPoint.getY(), 50, mPaint);

}

private void startAnimation() {

Point startPoint = new Point(50, 50);

Point endPoint = new Point(getWidth() - 50, getHeight() - 50);

ValueAnimator animator = ValueAnimator

.ofObject(new PointEvaluator(), startPoint, endPoint);

animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {

@Override

public void onAnimationUpdate(ValueAnimator animation) {

mPoint = ((Point) animation.getAnimatedValue());

LogUtil.i(mPoint.getX() + "------" + mPoint.getY());

invalidate();

}

});

ObjectAnimator colorAnimator = ObjectAnimator.ofObject(this, "color", new ColorEvaluator(),

"#0000ff", "#ff0000");

AnimatorSet animatorSet = new AnimatorSet();

animatorSet.play(animator).with(colorAnimator);

animatorSet.setDuration(5000);

animatorSet.start();

}

颜色的控制

public class ColorEvaluator implements TypeEvaluator {

private int currentRed = -1;

private int currentGreen = -1;

private int currentBlue = -1;

@Override

public String evaluate(float fraction, String startValue, String endValue) {

int startRed = Integer.parseInt(startValue.substring(1, 3), 16);

int startGreen = Integer.parseInt(startValue.substring(3, 5), 16);

int startBlue = Integer.parseInt(startValue.substring(5, 7), 16);

int endRed = Integer.parseInt(endValue.substring(1, 3), 16);

int endGreen = Integer.parseInt(endValue.substring(3, 5), 16);

int endBlue = Integer.parseInt(endValue.substring(5, 7), 16);

if (currentRed == -1) {

currentRed = startRed;

}

if (currentBlue == -1) {

currentBlue = startBlue;

}

if (currentGreen == -1) {

currentGreen = startGreen;

}

int diffRed = Math.abs(startRed - endRed);

int diffGreen = Math.abs(startGreen - endGreen);

int diffBlue = Math.abs(startBlue - endBlue);

if (currentRed != endRed) {

currentRed = getCurrentColor(startRed, endRed, diffRed, 0, fraction);

} else if (currentGreen != endGreen) {

currentGreen = getCurrentColor(startGreen, endGreen, diffGreen, diffRed, fraction);

} else if (currentBlue != endBlue) {

currentBlue = getCurrentColor(startBlue, endBlue, diffBlue, diffRed + diffGreen, fraction);

}

String currentColor = "#" + getHexString(currentRed) +

getHexString(currentGreen) +

getHexString(currentBlue);

LogUtil.i(currentColor);

return currentColor;

}

private int getCurrentColor(int startColor, int endColor,

int diffColor, int offset, float fraction) {

int currentColor = 0;

if (startColor > endColor) {

currentColor = (int) (startColor - (fraction * diffColor - offset));

if (currentColor < endColor) {

currentColor = endColor;

}

} else {

currentColor = (int) (startColor + (fraction * diffColor - offset));

if (currentColor > endColor) {

currentColor = endColor;

}

return currentColor;

}

private String getHexString(int value) {

String hexString = Integer.toHexString(value);

if (hexString.length() == 1) {

hexString = "0" + hexString;

}

return hexString;

}

效果:

32a01d26b66f

这里写图片描述