Android沿路径移动对象

Question

我已经创建了一个路径和圆圈，并在屏幕上显示它们如下:

public void onDraw(Canvas canvas){
        
        Path sPath = new Path();
        sPath.moveTo(100, 100);
        sPath.lineTo(300, 100);
        sPath.lineTo(300, 300);
        sPath.lineTo(100,300);
        sPath.lineTo(100,100);
        sPath.close();
        
        Paint ballPaint = new Paint();
        ballPaint.setColor(Color.GREEN);
        Paint pathPaint = new Paint();
        pathPaint.setColor(Color.BLUE);
        
        canvas.drawPath(sPath, ballPaint);
        canvas.drawCircle(100,100,20,pathPaint);
    }

我想让圆圈沿着路径移动，我该怎么做？

Answer 1

以下是我使用的动画师:

目的:沿路径“路径”移动 View “ View ”

v21+:

ValueAnimator pathAnimator = ObjectAnimator.ofFloat(view, "x", "y", path)

v11+:

ValueAnimator pathAnimator = ValueAnimator.ofFloat(0.0f, 1.0f);

pathAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
float[] point = new float[2];

@Override
    public void onAnimationUpdate(ValueAnimator animation) {
        float val = animation.getAnimatedFraction();
        PathMeasure pathMeasure = new PathMeasure(path, true);
        pathMeasure.getPosTan(pathMeasure.getLength() * val, point, null);
        view.setX(point[0]);
        view.setY(point[1]);
    }
});