软工划水日报-Android圆形图片 4/28

imageview都是那种方方的，但如果用在图像上要怎么办呢

今天我们就来写一个能显示圆形图片的Circleview

代码如下：

public class CircleImageview extends androidx.appcompat.widget.AppCompatImageView {

    public CircleImageview(Context context) {
        super(context);
        // TODO Auto-generated constructor stub
    }

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

    public CircleImageview(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();

        if(null == b)
        {
            return;
        }

        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)
            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 int color = 0xffa19774;
        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.parseColor("#BAB399"));
        canvas.drawCircle(sbmp.getWidth() / 2+0.7f, sbmp.getHeight() / 2+0.7f,
                sbmp.getWidth() / 2+0.1f, paint);
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        canvas.drawBitmap(sbmp, rect, rect, paint);


        return output;
    }

}

在布局中可以这样调用：

<com.example.ironfarm.CircleImageview
            android:layout_width="55dp"
            android:layout_height="55dp"
            android:src="@drawable/nep"
            />

好，就这些吧