对于上面提到的乔治·沃尔特斯二世，我只是把他的答案扩展了一下，以支持不同的圆角。这可以进一步优化(一些目标矩形重叠)，但不是很多。

我知道这个线程有点老了，但它是谷歌上关于如何在Android上圆角ImageViews的查询的顶级结果之一。

/**
 * Use this method to scale a bitmap and give it specific rounded corners.
 * @param context Context object used to ascertain display density.
 * @param bitmap The original bitmap that will be scaled and have rounded corners applied to it.
 * @param upperLeft Corner radius for upper left.
 * @param upperRight Corner radius for upper right.
 * @param lowerRight Corner radius for lower right.
 * @param lowerLeft Corner radius for lower left.
 * @param endWidth Width to which to scale original bitmap.
 * @param endHeight Height to which to scale original bitmap.
 * @return Scaled bitmap with rounded corners.
 */
public static Bitmap getRoundedCornerBitmap(Context context, Bitmap bitmap, float upperLeft,
        float upperRight, float lowerRight, float lowerLeft, int endWidth,
        int endHeight) {
    float densityMultiplier = context.getResources().getDisplayMetrics().density;

    // scale incoming bitmap to appropriate px size given arguments and display dpi
    bitmap = Bitmap.createScaledBitmap(bitmap, 
            Math.round(endWidth * densityMultiplier),
            Math.round(endHeight * densityMultiplier), true);

    // create empty bitmap for drawing
    Bitmap output = Bitmap.createBitmap(
            Math.round(endWidth * densityMultiplier),
            Math.round(endHeight * densityMultiplier), Config.ARGB_8888);

    // get canvas for empty bitmap
    Canvas canvas = new Canvas(output);
    int width = canvas.getWidth();
    int height = canvas.getHeight();

    // scale the rounded corners appropriately given dpi
    upperLeft *= densityMultiplier;
    upperRight *= densityMultiplier;
    lowerRight *= densityMultiplier;
    lowerLeft *= densityMultiplier;

    Paint paint = new Paint();
    paint.setAntiAlias(true);
    paint.setColor(Color.WHITE);

    // fill the canvas with transparency
    canvas.drawARGB(0, 0, 0, 0);

    // draw the rounded corners around the image rect. clockwise, starting in upper left.
    canvas.drawCircle(upperLeft, upperLeft, upperLeft, paint);
    canvas.drawCircle(width - upperRight, upperRight, upperRight, paint);
    canvas.drawCircle(width - lowerRight, height - lowerRight, lowerRight, paint);
    canvas.drawCircle(lowerLeft, height - lowerLeft, lowerLeft, paint);

    // fill in all the gaps between circles. clockwise, starting at top.
    RectF rectT = new RectF(upperLeft, 0, width - upperRight, height / 2);
    RectF rectR = new RectF(width / 2, upperRight, width, height - lowerRight);
    RectF rectB = new RectF(lowerLeft, height / 2, width - lowerRight, height);
    RectF rectL = new RectF(0, upperLeft, width / 2, height - lowerLeft);

    canvas.drawRect(rectT, paint);
    canvas.drawRect(rectR, paint);
    canvas.drawRect(rectB, paint);
    canvas.drawRect(rectL, paint);

    // set up the rect for the image
    Rect imageRect = new Rect(0, 0, width, height);

    // set up paint object such that it only paints on Color.WHITE
    paint.setXfermode(new AvoidXfermode(Color.WHITE, 255, AvoidXfermode.Mode.TARGET));

    // draw resized bitmap onto imageRect in canvas, using paint as configured above
    canvas.drawBitmap(bitmap, imageRect, imageRect, paint);

    return output;
}

在API 21的View类中添加了对圆形形状的剪切。

只要这样做:

创建一个可绘制的圆形形状，就像这样:

res - drawable round_outline xml。

<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <corners android:radius="10dp" />
    ...
</shape>

设置drawable作为ImageView的背景: android:背景= " @drawable / round_outline” 根据这个文档，那么你所需要做的就是添加android:clipToOutline="true"

不幸的是，有一个错误，无法识别该XML属性。幸运的是，我们仍然可以在Java中设置剪辑:

在你的活动或片段中:

下面是它的样子:

注意:

此方法适用于任何可绘制的形状(不仅仅是圆角)。它会剪辑ImageView到你在Drawable xml中定义的任何形状轮廓。

关于ImageViews的特别说明

setClipToOutline()仅在视图的背景设置为可绘制的形状时才有效。如果此背景形状存在，视图将形状的轮廓作为剪切和阴影目的的边界。

这意味着，如果你想使用setClipToOutline()圆角的ImageView，你的图像必须设置使用android:src而不是android:background(因为背景必须设置为您的圆角形状)。如果你必须使用背景来设置你的图像而不是src，你可以使用这个解决方案:

创建一个布局，并将其背景设置为可绘制的形状 将布局包装在ImageView周围(没有填充) ImageView(包括布局中的任何其他内容)现在将以圆角布局形状显示。

您应该扩展ImageView并绘制自己的圆角矩形。

如果你想在图像周围添加一个框架，你也可以在布局中将圆形框架叠加在图像视图的顶部。

例如，通过使用FrameLayout将帧叠加到原始图像上。FrameLayout的第一个元素将是你想要显示的图像。然后添加另一个ImageView与框架。第二个ImageView将显示在原始ImageView的顶部，因此Android将在原始ImageView上方绘制它的内容。

多亏了melanke，你可以使用一个自定义类并创建一个自定义循环ImageView。

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;

public class MLRoundedImageView extends android.support.v7.widget.AppCompatImageView {

    public MLRoundedImageView(Context context) {
        super(context);
    }

    public MLRoundedImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MLRoundedImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    protected void onDraw(Canvas canvas) {

        Drawable drawable = getDrawable();

        if (drawable == null) {
            return;
        }

        if (getWidth() == 0 || getHeight() == 0) {
            return;
        }
        Bitmap b = ((BitmapDrawable) drawable).getBitmap();
        Bitmap bitmap = b.copy(Bitmap.Config.ARGB_8888, true);

        int w = getWidth(), h = getHeight();

        Bitmap roundBitmap = getCroppedBitmap(bitmap, w);
        canvas.drawBitmap(roundBitmap, 0, 0, null);

    }

    public static Bitmap getCroppedBitmap(Bitmap bmp, int radius) {
        Bitmap sbmp;

        if (bmp.getWidth() != radius || bmp.getHeight() != radius) {
            float smallest = Math.min(bmp.getWidth(), bmp.getHeight());
            float factor = smallest / radius;
            sbmp = Bitmap.createScaledBitmap(bmp, (int)(bmp.getWidth() / factor), (int)(bmp.getHeight() / factor), false);
        } else {
            sbmp = bmp;
        }

        Bitmap output = Bitmap.createBitmap(radius, radius,
                Config.ARGB_8888);
        Canvas canvas = new Canvas(output);

        final int color = 0xffa19774;
        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, radius, radius);

        paint.setAntiAlias(true);
        paint.setFilterBitmap(true);
        paint.setDither(true);
        canvas.drawARGB(0, 0, 0, 0);
        paint.setColor(Color.parseColor("#BAB399"));
        canvas.drawCircle(radius / 2 + 0.7f,
                radius / 2 + 0.7f, radius / 2 + 0.1f, paint);
        paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
        canvas.drawBitmap(sbmp, rect, rect, paint);

        return output;
    }

}

然后在XML中使用它:

<your.package.name.MLRoundedImageView
..
/>

源

试试这个

Bitmap finalBitmap;
        if (bitmap.getWidth() != radius || bitmap.getHeight() != radius)
            finalBitmap = Bitmap.createScaledBitmap(bitmap, radius, radius,
                    false);
        else
            finalBitmap = bitmap;
        Bitmap output = Bitmap.createBitmap(finalBitmap.getWidth(),
                finalBitmap.getHeight(), Config.ARGB_8888);
        Canvas canvas = new Canvas(output);

        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, finalBitmap.getWidth(),
                finalBitmap.getHeight());

        paint.setAntiAlias(true);
        paint.setFilterBitmap(true);
        paint.setDither(true);
        canvas.drawARGB(0, 0, 0, 0);
        paint.setColor(Color.parseColor("#BAB399"));
        canvas.drawCircle(finalBitmap.getWidth() / 2 + 0.7f,
                finalBitmap.getHeight() / 2 + 0.7f,
                finalBitmap.getWidth() / 2 + 0.1f, paint);
        paint.setXfermode(new PorterDuffXfermode(
                android.graphics.PorterDuff.Mode.SRC_IN));
        canvas.drawBitmap(finalBitmap, rect, rect, paint);

        return output;

这是相当晚的响应，但对于任何其他人正在寻找这个，您可以执行以下代码手动圆角的图像。

http://www.ruibm.com/?p=184

这不是我的代码，但我用过它，它的工作非常出色。我将它用作ImageHelper类中的一个助手，并对它进行了一点点扩展，以便传入给定图像所需的羽化量。

最终代码如下所示:

package com.company.app.utils;

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Bitmap.Config;
import android.graphics.PorterDuff.Mode;

public class ImageHelper {
    public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, int pixels) {
        Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap
                .getHeight(), Config.ARGB_8888);
        Canvas canvas = new Canvas(output);

        final int color = 0xff424242;
        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
        final RectF rectF = new RectF(rect);
        final float roundPx = pixels;

        paint.setAntiAlias(true);
        canvas.drawARGB(0, 0, 0, 0);
        paint.setColor(color);
        canvas.drawRoundRect(rectF, roundPx, roundPx, paint);

        paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
        canvas.drawBitmap(bitmap, rect, rect, paint);

        return output;
    }
}