Android购物车运动轨迹动画

来源：互联网发布：apache for mac下载编辑：程序博客网时间：2024/05/16 23:33

public class PathBezierView extends View implements View.OnClickListener{    private int mStartPointX;    private int mStartPointY;    private int mEndPointX;    private int mEndPointY;    private int mFlagPointX;    private int mFlagPointY;    private int mMovePointX;    private int mMovePointY;    private Path mPath;    private Paint mPaintPath;    private Paint mPaintCircle;    public PathBezierView(Context context) {        super(context);    }    public PathBezierView(Context context, AttributeSet attrs) {        super(context, attrs);        mPath = new Path();        mPaintPath = new Paint(Paint.ANTI_ALIAS_FLAG);        mPaintPath.setStyle(Paint.Style.STROKE);        mPaintPath.setStrokeWidth(8);        mPaintCircle = new Paint(Paint.ANTI_ALIAS_FLAG);        mStartPointX = 100;        mStartPointY = 100;        mMovePointX = mStartPointX;        mMovePointY = mStartPointY;        mEndPointX = 600;        mEndPointY = 600;        mFlagPointX = 500;        mFlagPointY = 0;        setOnClickListener(this);    }    public PathBezierView(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        canvas.drawCircle(mStartPointX, mStartPointY, 20, mPaintCircle);        canvas.drawCircle(mEndPointX, mEndPointY, 20, mPaintCircle);        canvas.drawCircle(mMovePointX, mMovePointY, 20, mPaintCircle);        mPath.reset();        mPath.moveTo(mStartPointX, mStartPointY);        mPath.quadTo(mFlagPointX, mFlagPointY, mEndPointX, mEndPointY);        canvas.drawPath(mPath, mPaintPath);    }    @Override    public void onClick(View view) {        BezierEvaluator evaluator = new BezierEvaluator(new PointF(mFlagPointX, mFlagPointY));        ValueAnimator animator = ValueAnimator.ofObject(evaluator,                new PointF(mStartPointX, mStartPointY),                new PointF(mEndPointX, mEndPointY));        animator.setDuration(600);        animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {            @Override            public void onAnimationUpdate(ValueAnimator valueAnimator) {                PointF pointF = (PointF) valueAnimator.getAnimatedValue();                mMovePointX = (int) pointF.x;                mMovePointY = (int) pointF.y;                invalidate();            }        });        animator.setInterpolator(new AccelerateDecelerateInterpolator());        animator.start();    }}

public class BezierEvaluator implements TypeEvaluator<PointF> {    private PointF mFlagPoint;    public BezierEvaluator(PointF flagPoint) {        mFlagPoint = flagPoint;    }    @Override    public PointF evaluate(float v, PointF pointF, PointF t1) {        return BezierUtil.CalculateBezierPointForQuadratic(v, pointF, mFlagPoint, t1);    }}

public class BezierUtil {    /**     * B(t) = (1 - t)^2 * P0 + 2t * (1 - t) * P1 + t^2 * P2, t ∈ [0,1]     *     * @param t  曲线长度比例     * @param p0 起始点     * @param p1 控制点     * @param p2 终止点     * @return t对应的点     */    public static PointF CalculateBezierPointForQuadratic(float t, PointF p0, PointF p1, PointF p2) {        PointF point = new PointF();        float temp = 1 - t;        point.x = temp * temp * p0.x + 2 * t * temp * p1.x + t * t * p2.x;        point.y = temp * temp * p0.y + 2 * t * temp * p1.y + t * t * p2.y;        return point;    }    /**     * B(t) = P0 * (1-t)^3 + 3 * P1 * t * (1-t)^2 + 3 * P2 * t^2 * (1-t) + P3 * t^3, t ∈ [0,1]     *     * @param t  曲线长度比例     * @param p0 起始点     * @param p1 控制点1     * @param p2 控制点2     * @param p3 终止点     * @return t对应的点     */    public static PointF CalculateBezierPointForCubic(float t, PointF p0, PointF p1, PointF p2, PointF p3) {        PointF point = new PointF();        float temp = 1 - t;        point.x = p0.x * temp * temp * temp + 3 * p1.x * t * temp * temp + 3 * p2.x * t * t * temp + p3.x * t * t * t;        point.y = p0.y * temp * temp * temp + 3 * p1.y * t * temp * temp + 3 * p2.y * t * t * temp + p3.y * t * t * t;        return point;    }}

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