属性动画实战二

上一篇文章已经介绍个属性动画，参考属性动画实战一
今天开始第二个实战动画，仿雅虎加载动画
实现思路：
1、绘制指定个数的圆，并且开启旋转动画
2、内聚动画，绘制的圆向外扩展一定距离后，在开始内聚
3、扩散动画。
实现代码：
创建一个动画抽象类，其他动画类实现该类，完成绘制操作

 /**
     * 定义一个加载状态动画抽象类
     */
    private abstract class LoadStateAnimator {
        abstract void draw(Canvas canvas);
    }

绘制指定个数圆，并且开启旋转动画

 /**
     * 旋转动画
     */
    private class RotationAnimator extends LoadStateAnimator {
        private ValueAnimator mValueAnimator;
        //变化的角度
        private float changeAngle;
        public RotationAnimator() {
            fixAngle = (float) (2 * Math.PI / mCircleColors.length);
            mValueAnimator = ValueAnimator.ofFloat(0, 2 * (float) Math.PI);
            mValueAnimator.setDuration(ANIMATOR_DURATION);
            mValueAnimator.setInterpolator(new LinearInterpolator());
            mValueAnimator.addUpdateListener(animation -> {
                changeAngle = (float) animation.getAnimatedValue();
                invalidate();
            });

            //无限重复
            mValueAnimator.setRepeatCount(-1);
            mValueAnimator.start();
        }

        @Override
        void draw(Canvas canvas) {
            canvas.drawColor(mBgColor);
            //绘制指定个数的圆
            for (int i = 0; i < mCircleColors.length; i++) {
                mPaint.setColor(ContextCompat.getColor(getContext(), mCircleColors[i]));
                float cx = (float) (mCenterX + mCenterRadius * Math.cos(changeAngle + i * fixAngle));
                float cy = (float) (mCenterY + mCenterRadius * Math.sin(changeAngle + i * fixAngle));
                canvas.drawCircle(cx, cy, mRotationCircleRadius, mPaint);
            }
        }

        public void cancel() {
            mValueAnimator.cancel();
        }
    }

内聚动画，先进行向外扩展，然后向内缩进

/**
     * 内聚动画
     */
    private class MergeStateAnimator extends LoadStateAnimator {
        private ValueAnimator mValueAnimator;
        private float changeRadius;

        public MergeStateAnimator() {
            mValueAnimator = ValueAnimator.ofFloat(mCenterRadius, 0);
            mValueAnimator.setDuration(ANIMATOR_DURATION);

            //向外扩展一定距离后，向内缩的插值器
            mValueAnimator.setInterpolator(new AnticipateInterpolator(3));
            mValueAnimator.addUpdateListener(animation -> {
                changeRadius = (float) animation.getAnimatedValue();
                Log.e("YaHuLoadingView", "changeRadius：" + changeRadius);
                invalidate();
            });
            mValueAnimator.addListener(new AnimatorListenerAdapter() {
                @Override
                public void onAnimationEnd(Animator animation) {
                    mLoadStateAnimator = new ExtendStateAnimator();
                }
            });
            mValueAnimator.start();
        }

        @Override
        void draw(Canvas canvas) {
            canvas.drawColor(mBgColor);
            mPaint.setStyle(Paint.Style.FILL);
            for (int i = 0; i < mCircleColors.length; i++) {
                mPaint.setColor(ContextCompat.getColor(getContext(), mCircleColors[i]));
                float cx = (float) (mCenterX + changeRadius * Math.cos(i * fixAngle));
                float cy = (float) (mCenterY + changeRadius * Math.sin(i * fixAngle));
                canvas.drawCircle(cx, cy, mRotationCircleRadius, mPaint);
            }
        }
    }

扩散动画：

 /**
     * 扩展动画
     */
    private class ExtendStateAnimator extends LoadStateAnimator {
        private ValueAnimator mValueAnimator;
        private float changeCenterRadius;

        public ExtendStateAnimator() {
            mValueAnimator = ValueAnimator.ofFloat(0, mDiagonal);
            mValueAnimator.setDuration(ANIMATOR_DURATION);
            mValueAnimator.setInterpolator(new LinearInterpolator());
            mValueAnimator.addUpdateListener(animation -> {
                changeCenterRadius = (float) animation.getAnimatedValue();

                invalidate();
            });

            mValueAnimator.start();
        }

        @Override
        void draw(Canvas canvas) {
            mPaint.setColor(ContextCompat.getColor(getContext(), mCircleColors[1]));
            //画笔的宽度为屏幕对角线一半减去渐变的半径
            float strokeWidth = mDiagonal - changeCenterRadius;
            mPaint.setStrokeWidth(strokeWidth);
            mPaint.setStyle(Paint.Style.STROKE);
          //绘制的空心圆的半径等于画笔宽度一半加上渐变半径
            float radius = strokeWidth/2 + changeCenterRadius;
            canvas.drawCircle(mCenterX, mCenterY, radius, mPaint);
        }
    }

优化代码：

 /**
     * 进行代码优化
     * @param visibility
     */
    @Override
    public void setVisibility(int visibility) {
        super.setVisibility(INVISIBLE);
        //清除动画
        clearAnimation();
        //移除加载布局
        ViewGroup parent = (ViewGroup) getParent();
        if (parent !=null){
            parent.removeView(this);
        }
    }

完整代码：

/**
 * @author yifuyun
 * @date 2020/5/15
 */
public class YaHuLoadingView extends View {

    private final long ANIMATOR_DURATION = 5000;
    //当前加载的动画状态
    private LoadStateAnimator mLoadStateAnimator;

    //画笔
    private Paint mPaint;

    //需要绘制圆颜色总数
    private int[] mCircleColors;

    //中心点位置
    private int mCenterX, mCenterY;

    //屏幕对角线的一半
    private float mDiagonal;

    //中心圆的半径
    private int mCenterRadius;

    //绘制旋转圆的半径
    private int mRotationCircleRadius;

    //绘制View背景颜色
    private int mBgColor = Color.WHITE;

    //初始角度
    private float fixAngle;

    //是否所有动画都已经结束
    private boolean mIsAllAnimatorFinish = true;
    //实时记录当前旋转圆的角度
    private double[] mRotationCircleCurrentAngles;

    public YaHuLoadingView(Context context) {
        this(context, null);
    }

    public YaHuLoadingView(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public YaHuLoadingView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        initParams();
    }

    private void initParams() {
        mPaint = new Paint();
        mPaint.setAntiAlias(true);
        mPaint.setDither(true);

        mCircleColors = new int[]{R.color.orange, R.color.aqua, R.color.yellow,
                R.color.blue, R.color.green, R.color.pink};

        mRotationCircleCurrentAngles = new double[mCircleColors.length];

        mCenterX = getMeasuredWidth() / 2;
        mCenterY = getMeasuredHeight() / 2;
        mDiagonal = (float) Math.sqrt(mCenterX * mCenterX + mCenterY * mCenterY);
        mCenterRadius = mCenterX / 3;
        mRotationCircleRadius = mCenterRadius / 8;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        if (mLoadStateAnimator == null) {
            mLoadStateAnimator = new RotationAnimator();
        }

        mLoadStateAnimator.draw(canvas);

    }

    /**
     * 开启内聚动画
     */
    public void startMergeAnimator() {
        if (!mIsAllAnimatorFinish) {
            return;
        }
        mIsAllAnimatorFinish = false;
        if (mLoadStateAnimator instanceof RotationAnimator) {
            RotationAnimator animator = (RotationAnimator) mLoadStateAnimator;
            animator.cancel();
        }
        mLoadStateAnimator = new MergeStateAnimator();

    }

    /**
     * 定义一个加载状态动画抽象类
     */
    private abstract class LoadStateAnimator {
        abstract void draw(Canvas canvas);

        abstract void cancel();
    }

    /**
     * 旋转动画
     */
    private class RotationAnimator extends LoadStateAnimator {
        private ValueAnimator mValueAnimator;
        //变化的角度
        private float changeAngle;


        public RotationAnimator() {
            fixAngle = (float) (2 * Math.PI / mCircleColors.length);
            mValueAnimator = ValueAnimator.ofFloat(0, 2 * (float) Math.PI);
            mValueAnimator.setDuration(ANIMATOR_DURATION);
            mValueAnimator.setInterpolator(new LinearInterpolator());
            mValueAnimator.addUpdateListener(animation -> {
                changeAngle = (float) animation.getAnimatedValue();
                invalidate();
            });

            //无限重复
            mValueAnimator.setRepeatCount(-1);
            mValueAnimator.start();
        }

        @Override
        void draw(Canvas canvas) {
            canvas.drawColor(mBgColor);


            for (int i = 0; i < mCircleColors.length; i++) {
                mPaint.setColor(ContextCompat.getColor(getContext(), mCircleColors[i]));
                mRotationCircleCurrentAngles[i]= changeAngle + i * fixAngle;
                float cx = (float) (mCenterX + mCenterRadius * Math.cos(mRotationCircleCurrentAngles[i]));
                float cy = (float) (mCenterY + mCenterRadius * Math.sin(mRotationCircleCurrentAngles[i]));
                canvas.drawCircle(cx, cy, mRotationCircleRadius, mPaint);
            }
        }

        @Override
        public void cancel() {
            mValueAnimator.cancel();
            mValueAnimator.removeAllUpdateListeners();
        }
    }

    /**
     * 内聚动画
     */
    private class MergeStateAnimator extends LoadStateAnimator {
        private ValueAnimator mValueAnimator;
        private float changeRadius;
        public MergeStateAnimator() {
            mValueAnimator = ValueAnimator.ofFloat(mCenterRadius, 0);
            mValueAnimator.setDuration(ANIMATOR_DURATION);
            mValueAnimator.setInterpolator(new AnticipateInterpolator(3));
            mValueAnimator.addUpdateListener(animation -> {
                changeRadius = (float) animation.getAnimatedValue();
                Log.e("YaHuLoadingView", "changeRadius：" + changeRadius);
                invalidate();
            });
            mValueAnimator.addListener(new AnimatorListenerAdapter() {
                @Override
                public void onAnimationEnd(Animator animation) {
                    cancel();
                    mLoadStateAnimator = new ExtendStateAnimator();
                }
            });
            mValueAnimator.start();
        }

        @Override
        void draw(Canvas canvas) {
            canvas.drawColor(mBgColor);
            mPaint.setStyle(Paint.Style.FILL);
            for (int i = 0; i < mCircleColors.length; i++) {
                mPaint.setColor(ContextCompat.getColor(getContext(), mCircleColors[i]));
                float cx = (float) (mCenterX + changeRadius * Math.cos(mRotationCircleCurrentAngles[i]));
                float cy = (float) (mCenterY + changeRadius * Math.sin(mRotationCircleCurrentAngles[i]));
                canvas.drawCircle(cx, cy, mRotationCircleRadius, mPaint);
            }
        }

        @Override
        public void cancel() {
            mValueAnimator.cancel();
            mValueAnimator.removeAllUpdateListeners();
            mValueAnimator.removeAllListeners();
        }
    }

    /**
     * 扩展动画
     */
    private class ExtendStateAnimator extends LoadStateAnimator {
        private ValueAnimator mValueAnimator;
        private float changeCenterRadius;

        public ExtendStateAnimator() {
            mValueAnimator = ValueAnimator.ofFloat(0, mDiagonal);
            mValueAnimator.setDuration(ANIMATOR_DURATION);
            mValueAnimator.setInterpolator(new LinearInterpolator());
            mValueAnimator.addUpdateListener(animation -> {
                changeCenterRadius = (float) animation.getAnimatedValue();
                invalidate();
            });
            mValueAnimator.addListener(new AnimatorListenerAdapter() {
                @Override
                public void onAnimationEnd(Animator animation) {
                    mIsAllAnimatorFinish = true;
                }
            });
            mValueAnimator.start();
        }

        @Override
        void draw(Canvas canvas) {
            mPaint.setColor(ContextCompat.getColor(getContext(), mCircleColors[1]));
            float strokeWidth = mDiagonal - changeCenterRadius;
            mPaint.setStrokeWidth(strokeWidth);
            mPaint.setStyle(Paint.Style.STROKE);

            float radius = strokeWidth / 2 + changeCenterRadius;

            canvas.drawCircle(mCenterX, mCenterY, radius, mPaint);
        }

        @Override
        public void cancel() {
            mValueAnimator.cancel();
            mValueAnimator.removeAllUpdateListeners();
            mValueAnimator.removeAllListeners();
        }
    }

    /**
     * 进行代码优化
     *
     * @param visibility
     */
    @Override
    public void setVisibility(int visibility) {
        super.setVisibility(INVISIBLE);
        //清除动画
        clearAnimation();
        //移除加载布局
        ViewGroup parent = (ViewGroup) getParent();
        if (parent != null) {
            parent.removeView(this);
        }

    }

    @Override
    protected void onDetachedFromWindow() {
        super.onDetachedFromWindow();
        //取消动画
        if (mLoadStateAnimator != null) {
            mLoadStateAnimator.cancel();
            mLoadStateAnimator = null;
        }
    }
}