android实现图片圆角化实现三种方法

方法一

自定义ImageView

/**
 * 自定义的圆角矩形ImageView，可以直接当组件在布局中使用。
 * @author caizhiming
 *
 */
public class XCRoundRectImageView extends ImageView {

    private Paint paint;

    public XCRoundRectImageView(Context context) {
        this(context,null);
    }

    public XCRoundRectImageView(Context context, AttributeSet attrs) {
        this(context, attrs,0);
    }

    public XCRoundRectImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        paint  = new Paint();
    }

    /**
     * 绘制圆角矩形图片
     * @author caizhiming
     */
    @Override
    protected void onDraw(Canvas canvas) {
//
        Drawable drawable = getDrawable();
        if (null != drawable) {
            Bitmap bitmap = getBitmapFromDrawable(drawable);
//            Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap();
            Bitmap b = getRoundBitmap(bitmap, 20);
            final Rect rectSrc = new Rect(0, 0, b.getWidth(), b.getHeight());
            final Rect rectDest = new Rect(0,0,getWidth(),getHeight());
            paint.reset();
            canvas.drawBitmap(b, rectSrc, rectDest, paint);

        } else {
            super.onDraw(canvas);
        }
    }

    /**
     * 获取圆角矩形图片方法
     * @param bitmap
     * @param roundPx,一般设置成14
     * @return Bitmap
     * @author caizhiming
     */
    private Bitmap getRoundBitmap(Bitmap bitmap, int roundPx) {
        Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
                bitmap.getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(output);

        final int color = 0xff424242;

        final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
        final RectF rectF = new RectF(rect);
        paint.setAntiAlias(true);
        canvas.drawARGB(0, 0, 0, 0);
        paint.setColor(color);
        int x = bitmap.getWidth();

        canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
        paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
        canvas.drawBitmap(bitmap, rect, rect, paint);
        return output;
    }
}

/**
 * 把资源图片转换成Bitmap
 *
 * @param drawable
 *            资源图片
 * @return 位图
 */
public static Bitmap getBitmapFromDrawable(Drawable drawable) {
   int width = drawable.getIntrinsicWidth();
   int height = drawable.getIntrinsicHeight();
   Bitmap bitmap = Bitmap.createBitmap(width, height, drawable
         .getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
         : Bitmap.Config.RGB_565);
   Canvas canvas = new Canvas(bitmap);
   drawable.setBounds(-4, -4, width+4, height+4);
   drawable.draw(canvas);
   return bitmap;
}

方法二用Glide加载显示图片

Glide.with(mContext).load(mList.get(position).getImgUrl()).thumbnail(0.1f)
        .error(R.drawable.icon)
        .transform(new GlideRoundTransform(mContext,10))//设置弧度
        .into(holder.imageview);

public class GlideRoundTransform extends BitmapTransformation {

    private static float radius = 0f;

    public GlideRoundTransform(Context context) {
        this(context, 4);
    }

    public GlideRoundTransform(Context context, int dp) {
        super(context);
        this.radius = Resources.getSystem().getDisplayMetrics().density * dp;
    }

    @Override protected Bitmap transform(BitmapPool pool, Bitmap toTransform, int outWidth, int outHeight) {
        return roundCrop(pool, toTransform);
    }

    private static Bitmap roundCrop(BitmapPool pool, Bitmap source) {
        if (source == null) return null;

        Bitmap result = pool.get(source.getWidth(), source.getHeight(), Bitmap.Config.ARGB_8888);
        if (result == null) {
            result = Bitmap.createBitmap(source.getWidth(), source.getHeight(), Bitmap.Config.ARGB_8888);
        }

        Canvas canvas = new Canvas(result);
        Paint paint = new Paint();
        paint.setShader(new BitmapShader(source, BitmapShader.TileMode.CLAMP, BitmapShader.TileMode.CLAMP));
        paint.setAntiAlias(true);
        RectF rectF = new RectF(0f, 0f, source.getWidth(), source.getHeight());
        canvas.drawRoundRect(rectF, radius, radius, paint);
        return result;
    }

    @Override public String getId() {
        return getClass().getName() + Math.round(radius);
    }

方法三

/** */
/**
 * 把图片变成圆角
 *
 * @param bitmap
 *            需要修改的图片
 * @param pixels
 *            圆角的弧度
 * @return 圆角图片
 */
public static Bitmap toRoundCorner(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;
}