绘制在Android画布空心圆 [英] Draw a hollow circle on an Android Canvas

问题描述

我的工作创建一个自定义视图，用户可以选择的角度。下面是最终的结果应该是什么样子的例子：

I am working on creating a custom view where a user can select an angle. Below is an example of what the end result should look like:

我用下面的code实现这一目标：

I am achieving this with the following code:

mPaint.setColor(Color.BLACK);
canvas.drawCircle((int) (mSize.right / 2), (int) (mSize.bottom / 2),
        mWidthOutside, mPaint);

mPaint.setColor(Color.LTGRAY);
canvas.drawCircle((int) (mSize.right / 2), (int) (mSize.bottom / 2),
        mWidthInside, mPaint);

通过做这种方式的问题，就是背景是一个静态 LTGRAY ，我希望能够透明。

The problem with doing it this way, is the background is a static LTGRAY, which I hope to make Transparent.

我怎么会去离开圆心透明？

How would I go about leaving the center of the circle transparent?

我曾尝试以下的，希望在 drawArc 功能只会造成一条线涂料的宽度，而不是填补了中心。它在面对填充的中心。

I have tried the following hoping the the drawArc function would only create a line the width of the paint, and not fill the center. It does in face fill the center.

RectF rectF = new RectF(centerX - mRadius, centerY - mRadius, centerX
            + mRadius, centerY + mRadius);
canvas.drawArc(rectF, 0, 360, false, mPaint);

这是如何保持圆心建议透明？

Suggestions on how to keep the center of the circle transparent?

推荐答案

由于问:)
解决的办法是设置样式为 Paint.Style.STROKE

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