Android图片压缩

Android

原文：https://www.zybuluo.com/Tyhj/note/666195
Android中，图片展示的时候可以用各种框架，图片工具来很好的展示。但是涉及到图片上传的时候，比如上传头像什么的，我们就可以先将图片压缩一下再上传。

//计算图片的缩放值
    public static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
        final int height = options.outHeight;
        final int width = options.outWidth;
        int inSampleSize = 1;
        if (height > reqHeight || width > reqWidth) {
            final int heightRatio = Math.round((float) height/ (float) reqHeight);
            final int widthRatio = Math.round((float) width / (float) reqWidth);
            inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
        }
        return inSampleSize;
    }

 //图片压缩
    public static void ImgCompress(String filePath,File newFile,int IMAGE_SIZE) {
        //图片质量百分比
        int imageMg=100;
        final BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeFile(filePath, options);
        //规定要压缩图片的分辨率
        options.inSampleSize = calculateInSampleSize(options,1080,1920);
        options.inJustDecodeBounds = false;
        Bitmap bitmap= BitmapFactory.decodeFile(filePath, options);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.JPEG, imageMg, baos);
        //如果文件大于100KB就进行质量压缩，每次压缩比例增加百分之五
        while (baos.toByteArray().length / 1024 > IMAGE_SIZE&&imageMg>60){
            baos.reset();
            imageMg-=5;
            bitmap.compress(Bitmap.CompressFormat.JPEG, imageMg, baos);
        }
        //然后输出到指定的文件中
        FileOutputStream fos = null;
        try {
            fos = new FileOutputStream(newFile);
            fos.write(baos.toByteArray());
            fos.flush();
            fos.close();
            baos.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }