Android move object along a path
Here are the animators I use:
Purpose: Move View "view" along Path "path"
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]);
}
});
Yes, it's possible to move image along path. I will provide simple solution to show the principle. The following code will animate the circle along the path.
int iCurStep = 0;// current animation step
@Override
protected void onDraw(Canvas canvas) {
PathMeasure pm = new PathMeasure(sPath, false);
float fSegmentLen = pm.getLength() / 20;//we'll get 20 points from path to animate the circle
float afP[] = {0f, 0f};
if (iCurStep <= 20) {
pm.getPosTan(fSegmentLen * iCurStep, afP, null);
canvas.drawCircle(afP[0],afP[1],20,pathPaint);
iCurStep++;
invalidate();
} else {
iCurStep = 0;
};
};