android - 使 ImageView 变圆(不是图像)

Question

要求是:

请求 1:从 url 中获取图像

R2:将它们保存在缓存中

R3: 使 ImageView 变圆而不是图像

所以对于 R1 和 R2，我找到了一个库: http://loopj.com/android-smart-image-view/

对于 R3，我做了很多研发工作，我发现的所有内容都会转换图像而不是 ImageView。这是我搜索过的:

Mask ImageView with round corner background

How to make an ImageView with rounded corners?

https://github.com/vinc3m1/RoundedImageView

https://github.com/lopspower/CircularImageView

我知道可以使用 ImageView 位图并使图像四舍五入，但是对于我想使用的特定库，这是不可能的(可能使用非常复杂的线程)。

所以请帮我把 ImageView 弄圆而不是图像。

Answer 1

所以这是简约版本:

class RoundImageView extends ImageView {
    private static final int RADIUS = 32;
    private Paint mPaint;
    private Paint mSrcIn;
    private RectF mRect;

    public RoundImageView(Context context) {
        super(context);
//        setBackgroundColor(0xffffffff);
        mSrcIn = new Paint();
        mSrcIn.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mRect = new RectF();
    }

    @Override
    public void onDraw(Canvas canvas) {
        Drawable dr = getDrawable();
        if (dr != null) {
            mRect.set(dr.getBounds());
            getImageMatrix().mapRect(mRect);
            mRect.offset(getPaddingLeft(), getPaddingTop());

            int rtc = canvas.saveLayer(mRect, null, Canvas.ALL_SAVE_FLAG);
            // draw DST
            canvas.drawRoundRect(mRect, RADIUS, RADIUS, mPaint);

            canvas.saveLayer(mRect, mSrcIn, Canvas.ALL_SAVE_FLAG);
            // draw SRC
            super.onDraw(canvas);
            canvas.restoreToCount(rtc);
        }
    }
}

或者在不使用硬件加速时使用更短的一个，你可以使用 Canvas.clipPath:

class RoundImageViewClipped extends ImageView {
    private static final int RADIUS = 32;
    private RectF mRect;
    private Path mClip;

    public RoundImageViewClipped(Context context) {
        super(context);
//        setBackgroundColor(0xffffffff);
        mRect = new RectF();
        mClip = new Path();
    }

    @Override
    public void onDraw(Canvas canvas) {
        Drawable dr = getDrawable();
        if (dr != null) {
            mRect.set(dr.getBounds());
            getImageMatrix().mapRect(mRect);
            mRect.offset(getPaddingLeft(), getPaddingTop());
            mClip.reset();
            mClip.addRoundRect(mRect, RADIUS, RADIUS, Direction.CCW);

            canvas.clipPath(mClip);
            super.onDraw(canvas);
        }
    }
}