Question

如何在弧的边缘添加小圆。
并且它也应该在时钟方向上以弧形边缘移动现在我通过改变扫掠角度成功地为弧设置动画还有黑点。

enter image description here

下面是getView和动画类的代码

--- init method and implement constructor ----

 mRectF = new RectF(mWidth / 2 - 360, mHeight / 2 - 360, mWidth / 2 + 360, mHeight / 2 + 360);

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    //draw circle background
    mPaint.setColor(getResources().getColor(R.color.timer_background_color));
    canvas.drawCircle(mWidth / 2, mHeight / 2, 360, mPaint);

    mPaint.setColor(getResources().getColor(R.color.actionbar_back_color));
    canvas.drawArc(mRectF, mStartAnagle, mSweepAngle, false, mPaint);
}

public class TimerAnimation extends Animation{

    public TimerAnimation (float startAngle, float sweepAngle, long duration) {
        mStartAnagle = startAngle;
        mSweepAngle = sweepAngle;
        setDuration(duration);
        setRepeatCount(Animation.INFINITE);
        setInterpolator(new LinearInterpolator());
    }

    @Override
    protected void applyTransformation(float interpolatedTime, Transformation t) {
        if (!isComplete) {
            mSweepAngle = mSweepAngle + 6;
            if (mSweepAngle >= 360) {
                isComplete = true;
                mSweepAngle = 360;
            }
        } else {
            mStartAnagle = mStartAnagle + 6;
            mSweepAngle = mSweepAngle - 6;
            if (mStartAnagle >= 360)
                mStartAnagle = 0;
            if (mStartAnagle == 270 || mSweepAngle <= 0) {
                isComplete = false;
                mSweepAngle = 0;
            }
        }
        invalidate();
    }
}

Answer 1

也许您应该使用Path：

Path path = new Path();
// Set the starting position of the path to (0,0).
path.moveTo(0, 0);
path.arcTo(...); //draw your arc here
path.circleTo(); //draw a small circle here at the end of arc

也许你应该calc the arc's end position并用作小圈子的中心。

Answer 2

第1步：计算黑点的位置

建议中心位置是（centerX，centerY），黑点的位置是（x，y），然后，

x = radius * cos(mStartAnagle+mSweepAngle) + centerX;
y = radius * sin(mStartAnagle+mSweepAngle) + centerY;

第2步：绘制黑点

建议点图像为R.drawable.dot，

Bitmap bitmap = BitmapFactory.decodeResource(getResources(),R.drawable.dot) 
                             .copy(Bitmap.Config.ARGB_8888, true);
canvas.drawBitmap(bitmap, x, y, null);

在arc android的边缘添加一个圆圈？

2 个答案: