Android 图片工具类整理

1.将图片转换成圆形

 /** 
    * 转换图片成圆形 
    * @param bitmap 传入Bitmap对象 
    * @return 
    */ 
    public static Bitmap toRoundBitmap(Bitmap bitmap) { 
        int width = bitmap.getWidth(); 
        int height = bitmap.getHeight(); 
        float roundPx; 
        float left,top,right,bottom,dst_left,dst_top,dst_right,dst_bottom; 
        if (width <= height) { 
        roundPx = width / 2; 
        top = 0; 
        bottom = width; 
        left = 0; 
        right = width; 
        height = width; 
        dst_left = 0; 
        dst_top = 0; 
        dst_right = width; 
        dst_bottom = width; 
        } else { 
        roundPx = height / 2; 
        float clip = (width - height) / 2; 
        left = clip; 
        right = width - clip; 
        top = 0; 
        bottom = height; 
        width = height; 
        dst_left = 0; 
        dst_top = 0; 
        dst_right = height; 
        dst_bottom = height; 
        } 
        Bitmap output = Bitmap.createBitmap(width, 
        height, Config.ARGB_8888); 
        Canvas canvas = new Canvas(output); 
        final int color = 0xff424242; 
        final Paint paint = new Paint(); 
        final Rect src = new Rect((int)left, (int)top, (int)right, (int)bottom); 
        final Rect dst = new Rect((int)dst_left, (int)dst_top, (int)dst_right, (int)dst_bottom); 
        final RectF rectF = new RectF(dst); 
        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, src, dst, paint); 
        return output; 
    } 

2.将图片缩小后变成圆形（图片本身会被修改）

/**
     * 处理图片(缩小、变成圆形)
     * @return 返回处理后的图片
     */
    public static Bitmap HandlePhotoFromCamera(){
        BitmapFactory.Options op = new BitmapFactory.Options();
        op.inSampleSize = 6; // 这个数字越大,图片大小越小.
        // 设置图片的大小
        Bitmap bitMap = BitmapFactory.decodeFile(BitmapUtil.PHOTONAME);
        int width = bitMap.getWidth();
        int height = bitMap.getHeight();
        // 设置想要的大小
        int newWidth = 250;
        int newHeight = 250;
        // 计算缩放比例
        float scaleWidth = ((float) newWidth) / width;
        float scaleHeight = ((float) newHeight) / height;
        // 取得想要缩放的matrix参数
        Matrix matrix = new Matrix();
        matrix.postScale(scaleWidth, scaleHeight);
        // 得到新的图片
        //bitMap = Bitmap.createBitmap(bitMap, 0, 0, width, height,
        //      matrix, true);
        // canvas.drawBitmap(bitMap, 0, 0, paint)

        Bitmap pic = null;
        pic = BitmapUtil.toRoundBitmap(BitmapFactory.decodeFile(BitmapUtil.PHOTONAME, op));//将图片变成圆形
        FileOutputStream b = null;
        ;
        try {
            b = new FileOutputStream(BitmapUtil.PHOTONAME);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        if (pic != null) {
            pic.compress(Bitmap.CompressFormat.JPEG, 30, b);
        }
        return pic;
    }

3 bitmap与string转换以及base64编码

    //// 将Bitmap转换成字符串  
    public String bitmaptoString(Bitmap bitmap) {   
        String string = null;  
        ByteArrayOutputStream bStream = new ByteArrayOutputStream();  
        bitmap.compress(CompressFormat.PNG, 100, bStream);  
        byte[] bytes = bStream.toByteArray();  
        string = Base64.encodeToString(bytes, Base64.DEFAULT);  
        return string;  

    }
    public Bitmap stringtoBitmap(String string) {         
        // 将字符串转换成Bitmap类型  
        Bitmap bitmap = null;  
        try {  
                byte[] bitmapArray;  
                bitmapArray = Base64.decode(string, Base64.DEFAULT);  
                bitmap = BitmapFactory.decodeByteArray(bitmapArray, 0,  
                                bitmapArray.length);  
        } catch (Exception e) {  
               e.printStackTrace();  
        }  
        return bitmap;  
    }  
    //将bytep数组按base64 编码
    public static String bytesToBase64(byte[] data) {
        if (data == null) {
            return null;
        }
        return Base64.encodeToString(data, Base64.DEFAULT);
    }

4 根据本地Uri获取bitmap对象后处理

private Bitmap getBitmapFromUri(Uri uri) {
        Bitmap bitmap = null;
        try {
            BitmapFactory.Options options = new BitmapFactory.Options();
            options.inJustDecodeBounds = true;
            bitmap = BitmapFactory.decodeStream(getContentResolver()
                    .openInputStream(uri), null, options);
            int picWidth = options.outWidth;
            int picHeight = options.outHeight;
            WindowManager windowManager = getWindowManager();
            Display display = windowManager.getDefaultDisplay();
            int screenWidth = display.getWidth();
            int screenHeight = display.getHeight();
            options.inSampleSize = 1;
            if (picWidth > picHeight) {
                if (picWidth > screenWidth)
                    options.inSampleSize = picWidth / screenWidth;
            } else {
                if (picHeight > screenHeight)
                    options.inSampleSize = picHeight / screenHeight;
            }
            options.inJustDecodeBounds = false;
            bitmap = BitmapFactory.decodeStream(getContentResolver()
                    .openInputStream(uri), null, options);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
        return bitmap;
    }

5.将图片压缩后转换成byte数组

ByteArrayOutputStream baos = new ByteArrayOutputStream();
fianBitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);// 100不压缩
byte[] bitmapByte = baos.toByteArray();

之后转换成base64编码即可上传到服务器

6.从字节数组中获取bitmap

public static Bitmap getBitmapFromBytes(byte[] data) {
        if (data == null) {
            return null;
        }
        return BitmapFactory.decodeByteArray(data, 0, data.length);// 从字节数组解码位图
    }