Android中的图片圆角怎么实现

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Android 开发中，经常需要对图片进行二次处理，比如添加圆角效果 或 显示圆形图片；

方法一

通过第三方框架 Glide 设置圆角效果；

写法1：

RequestOptions options = new RequestOptions().error(R.drawable.img_load_failure).bitmapTransform(new RoundedCorners(30));//图片圆角为30Glide.with(this).load(URL) //图片地址                .apply(options)                .into(ImagView);

写法2：

RequestOptions requestOptions = new RequestOptions();requestOptions.placeholder(R.drawable.ic_launcher_background);requestOptions.circleCropTransform();requestOptions.transforms( new RoundedCorners(30));Glide.with(this).load(URL) //图片地址                .apply(options)                .into(ImagView);

写法3：

RequestOptions options = new RequestOptions().centerCrop() .transform(new RoundTransform(this,30)); Glide.with(this).load(URL) //图片地址                .apply(options)                .into(ImagView);

public class RoundTransform extends BitmapTransformation {     private static float radius = 0f;     public RoundTransform(Context context) {         this(context, 4);     }        public RoundTransform(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) {         Bitmap bitmap = TransformationUtils.centerCrop(pool, toTransform, outWidth, outHeight);         return roundCrop(pool, bitmap);     }        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;     }        public String getId() {         return getClass().getName() + Math.round(radius);     }        @Override     public void updateDiskCacheKey(MessageDigest messageDigest) {        }}

方法二

自定义ImageView 设置圆角效果；

ImageView iv = findViewById(R.id.iv); Bitmap bitmap =BitmapFactory.decodeResource(getResources(), R.drawable.fengjing);        Bitmap outBitmap =getRoundBitmapByShader(bitmap, 500,300,20, 3);        iv.setImageBitmap(outBitmap);

public class RoundRectImageView extends ImageView{     private Paint paint;     public RoundRectImageView(Context context) {        this(context,null);    }     public RoundRectImageView(Context context, AttributeSet attrs) {        this(context, attrs,0);    }     public RoundRectImageView(Context context, AttributeSet attrs, int defStyle) {        super(context, attrs, defStyle);        paint  = new Paint();    }     /**     * 绘制圆角矩形图片     */    @Override    protected void onDraw(Canvas canvas) {        Drawable drawable = getDrawable();        if (null != drawable) {            Bitmap bitmap = getBitmapFromDrawable(drawable);//            Bitmap bitmap = ((BitmapDrawable) drawable).getBitmap();            Bitmap b = getRoundBitmapByShader(bitmap,getWidth(),getHeight(), 50,0);            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);        }    }     /**     * 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;    }     public static Bitmap getRoundBitmapByShader(Bitmap bitmap, int outWidth, int outHeight, int radius, int boarder) {        if (bitmap == null) {            return null;        }        int width = bitmap.getWidth();        int height = bitmap.getHeight();        float widthScale = outWidth * 1f / width;        float heightScale = outHeight * 1f / height;         Matrix matrix = new Matrix();        matrix.setScale(widthScale, heightScale);        //创建输出的bitmap        Bitmap desBitmap = Bitmap.createBitmap(outWidth, outHeight, Bitmap.Config.ARGB_8888);        //创建canvas并传入desBitmap，这样绘制的内容都会在desBitmap上        Canvas canvas = new Canvas(desBitmap);        Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);        //创建着色器        BitmapShader bitmapShader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);        //给着色器配置matrix        bitmapShader.setLocalMatrix(matrix);        paint.setShader(bitmapShader);        //创建矩形区域并且预留出border        RectF rect = new RectF(boarder, boarder, outWidth - boarder, outHeight - boarder);        //把传入的bitmap绘制到圆角矩形区域内        canvas.drawRoundRect(rect, radius, radius, paint);         if (boarder > 0) {            //绘制boarder            Paint boarderPaint = new Paint(Paint.ANTI_ALIAS_FLAG);            boarderPaint.setColor(Color.GREEN);            boarderPaint.setStyle(Paint.Style.STROKE);            boarderPaint.setStrokeWidth(boarder);            canvas.drawRoundRect(rect, radius, radius, boarderPaint);        }        return desBitmap;    } }

方法三

对图片进行处理，还可以加边框；

/** * 通过BitmapShader实现圆形边框 * @param bitmap  * @param outWidth 输出的图片宽度 * @param outHeight 输出的图片高度 * @param radius 圆角大小 * @param boarder 边框宽度 */public static Bitmap getRoundBitmapByShader(Bitmap bitmap, int outWidth, int outHeight, int radius, int boarder) {    if (bitmap == null) {        return null;    }    int height = bitmap.getHeight();    int width = bitmap.getWidth();        float widthScale = outWidth * 1f / width;    float heightScale = outHeight * 1f / height;     Matrix matrix = new Matrix();    matrix.setScale(widthScale, heightScale);    //创建输出的bitmap    Bitmap desBitmap = Bitmap.createBitmap(outWidth, outHeight, Bitmap.Config.ARGB_8888);    //创建canvas并传入desBitmap，这样绘制的内容都会在desBitmap上    Canvas canvas = new Canvas(desBitmap);    Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);    //创建着色器    BitmapShader bitmapShader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);    //给着色器配置matrix    bitmapShader.setLocalMatrix(matrix);    paint.setShader(bitmapShader);    //创建矩形区域并且预留出border    RectF rect = new RectF(boarder, boarder, outWidth - boarder, outHeight - boarder);    //把传入的bitmap绘制到圆角矩形区域内    canvas.drawRoundRect(rect, radius, radius, paint);     if (boarder > 0) {        //绘制boarder        Paint boarderPaint = new Paint(Paint.ANTI_ALIAS_FLAG);        boarderPaint.setColor(Color.GREEN);        boarderPaint.setStyle(Paint.Style.STROKE);        boarderPaint.setStrokeWidth(boarder);        canvas.drawRoundRect(rect, radius, radius, boarderPaint);    }    return desBitmap;}

实现圆形和边框：

/** * 通过BitmapShader实现圆形边框 * @param bitmap  * @param outWidth 输出的图片宽度 * @param outHeight 输出的图片高度 * @param boarder 边框大小 */public static Bitmap getCircleBitmapByShader(Bitmap bitmap, int outWidth, int outHeight, int boarder) {int radius;int width = bitmap.getWidth();int height = bitmap.getHeight();float widthScale = outWidth * 1f / width;float heightScale = outHeight * 1f / height; Bitmap desBitmap = Bitmap.createBitmap(outWidth, outHeight, Bitmap.Config.ARGB_8888);if (outHeight > outWidth) {    radius = outWidth / 2;} else {    radius = outHeight / 2;}//创建canvasCanvas canvas = new Canvas(desBitmap);Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);BitmapShader bitmapShader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);Matrix matrix = new Matrix();matrix.setScale(widthScale, heightScale);bitmapShader.setLocalMatrix(matrix);paint.setShader(bitmapShader);canvas.drawCircle(outWidth / 2, outHeight / 2, radius - boarder, paint);if (boarder > 0) {    //绘制boarder    Paint boarderPaint = new Paint(Paint.ANTI_ALIAS_FLAG);    boarderPaint.setColor(Color.GREEN);    boarderPaint.setStyle(Paint.Style.STROKE);    boarderPaint.setStrokeWidth(boarder);    canvas.drawCircle(outWidth / 2, outHeight / 2, radius - boarder, boarderPaint);}return desBitmap;}

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