圆形ImageView，加上自定义属性，可以设置边框的颜色和宽度（8以上的版本可以用前景色加padding实现）

摘自不知道什么时候copy过来的代码（忘记来源了）~~

 public class CustomCircleImageView extends android.support.v7.widget.AppCompatImageView {
    private final String TAG = "TAG.CustomView";

    /**
     * 边框画笔的颜色
     */
    private int frameColor;
    /**
     * 边框的宽度
     */
    private float frameWidth;

     private Paint mPaint = new Paint();

    public CustomCircleImageView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.CustomCircleImageView);
        frameWidth = array.getDimension(R.styleable.CustomCircleImageView_frame_width, 6);
        frameColor = array.getColor(R.styleable.CustomCircleImageView_frame_color, Color.GREEN);
        array.recycle();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        mPaint.setAntiAlias(true);
        //这里的颜色决定了边缘的颜色
        mPaint.setColor(frameColor);
        if ( getDrawable()== null) {
            return;
        }
        if (getWidth() == 0 || getHeight() == 0) {
            return;
        }
        // 注意内存泄漏，实际情况中不能这么写的
        Bitmap bitmap = ((BitmapDrawable)  getDrawable()).getBitmap().copy(Bitmap.Config.ARGB_8888, true);
        int w = getWidth();
        int h = getHeight();
        //圆形ImageView的半径为布局中的ImageView定义大小
        Bitmap roundBitmap = getCroppedBitmap(bitmap, w);
        canvas.drawARGB(0, 0, 0, 0);
        canvas.drawCircle(w / 2, h / 2, w / 2, mPaint);
        canvas.drawBitmap(roundBitmap, 0, 0, null);
    }

    public Bitmap getCroppedBitmap(Bitmap bmp, int radius) {
        Bitmap sbmp;
        if (bmp.getWidth() != radius || bmp.getHeight() != radius) {
            sbmp = Bitmap.createScaledBitmap(bmp, radius, radius, false);
        } else {
            sbmp = bmp;
        }
        Bitmap output = Bitmap.createBitmap(sbmp.getWidth(), sbmp.getHeight(),     Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(output);
        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, sbmp.getWidth(), sbmp.getHeight());
        paint.setAntiAlias(true);
        paint.setFilterBitmap(true);
        paint.setDither(true);
        canvas.drawARGB(0, 0, 0, 0);
        paint.setColor(Color.WHITE);
        //第三个参数减去的数值为白边的宽度.
        canvas.drawCircle(sbmp.getWidth() / 2, sbmp.getHeight() / 2, sbmp.getHeight() / 2 -frameWidth, paint);
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        canvas.drawBitmap(sbmp, rect, rect, paint);
        return output;
    }
}

自定义属性

    <!--这是自定义属性-->
    <declare-styleable name="CustomCircleImageView">
        <attr name="frame_color" format="color"/>
        <attr name="frame_width" format="dimension"/>
    </declare-styleable>

布局文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    <!--自定义属性，这个要加上-->
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#222222"
    android:orientation="vertical">

    <!--图片只能src，别用背景属性-->
    <com.xxx.CustomCircleImageView
        android:layout_width="60dp"
        android:layout_height="60dp"
        android:src="@mipmap/ic_2"
       <!--这个是定义边框的颜色-->
        app:frame_color="@color/colorPrimary"
       <!--这个是定义边框的宽度-->
        app:frame_width="3dp" />

    <com.xxx.CustomCircleImageView
        android:layout_width="60dp"
        android:layout_height="60dp"
        android:src="@mipmap/ic_1r"
        app:frame_color="@color/colorAccent"
         app:frame_width="@dimen/dp_10" />
</LinearLayout>