Android三种常见的图片压缩方式

 public void getBitmap(String imgPath, String outPath) {  
        BitmapFactory.Options newOpts = new BitmapFactory.Options();  
        newOpts.inJustDecodeBounds = false;  
        newOpts.inPurgeable = true;  
        newOpts.inInputShareable = true;  
        // Do not compress  
        newOpts.inSampleSize = 1;  
        newOpts.inPreferredConfig = Config.RGB_565;  
        storeImage(bitmap, outPath); //保存图片
    }

/**
     * 把bitmap转化成图片存储在本地
     *
     * @param bitmap
     * @param outPath 本地的存储路径
     * @throws FileNotFoundException
     */
    public static boolean storeImage(Bitmap bitmap, String outPath) throws FileNotFoundException {
        FileOutputStream os = new FileOutputStream(outPath);
        boolean compressResult = bitmap.compress(Bitmap.CompressFormat.JPEG, 100, os);
        return compressResult;
    }

/**
     * 按比例压缩
     *
     * @param path    原图片路径
     * @param targetW 压缩后宽度
     * @param targetH 压缩后高度
     * @return 压缩后的图片的保存路径
     */
    public static String compressScale(String path,, String outPath, int targetW, int targetH) throws FileNotFoundException {
        // 获取option  
        BitmapFactory.Options options = new BitmapFactory.Options();
        // inJustDecodeBounds设置为true,这样使用该option decode出来的Bitmap是null，  
        // 只是把长宽存放到option中  
        options.inJustDecodeBounds = true;
        // 此时bitmap为null  
        Bitmap bitmap = BitmapFactory.decodeFile(path, options);
        int inSampleSize = 1; // 1是不缩放  
        // 计算宽高缩放比例  
        int inSampleSizeW = options.outWidth / targetW;
        int inSampleSizeH = options.outHeight / targetH;
        // 最终取大的那个为缩放比例，这样才能适配，例如宽缩放3倍才能适配屏幕，而  
        // 高不缩放就可以，那样的话如果按高缩放，宽在屏幕内就显示不下了  
        if (inSampleSizeW > inSampleSizeH) {
            inSampleSize = inSampleSizeW;
        } else {
            inSampleSize = inSampleSizeH;
        }
        // 一定要记得将inJustDecodeBounds设为false，否则Bitmap为null  
        options.inJustDecodeBounds = false;
        // 设置缩放比例(采样率)  
        options.inSampleSize = inSampleSize;
        bitmap = BitmapFactory.decodeFile(path, options);
        boolean isSuccess = storeImage(bitmap, outPath);
        if (isSuccess) {
            return outPath;
        }
        return "";
    }

/**
     * 获取本地文件大小
     *
     * @param imgPath 图片的路径
     * @return 图片实际的大小，单位byte
     */
    public static int getFileSize(String imgPath) {
        int size = 0;
        try {
            FileInputStream fis = new FileInputStream(new File(imgPath));
            size = fis.available();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return size;
    }

compile 'top.zibin:Luban:1.1.3'

private void lunBanPress(String path) {
        String pressPath = Environment.getExternalStorageDirectory().getPath();
        Luban.with(this)
                .load(path)                                   // 传人要压缩的图片列表
                .ignoreBy(100)                                  // 忽略不压缩图片的大小
                .setTargetDir(pressPath)                        // 设置压缩后文件存储位置
                .setCompressListener(new OnCompressListener() { //设置回调
                    @Override
                    public void onStart() {
                        // TODO 压缩开始前调用，可以在方法内启动 loading UI
                        Log.i(TAG, "onStart:开始鲁班压缩 ");
                    }

                    @Override
                    public void onSuccess(File file) {
                        // TODO 压缩成功后调用，返回压缩后的图片文件
                        Glide.with(activity).load(file).into(iv2);
                        Log.i(TAG, "onSuccess: 鲁班压缩成功 ：");
                        try {
                            int size = new FileInputStream(file).available();
                            Log.i("tag", "鲁班压缩 size--->:"   "byte:"   size   "    kb:"
                                      (float) size / 1024);
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }

                    @Override
                    public void onError(Throwable e) {
                        // TODO 当压缩过程出现问题时调用
                        Log.i(TAG, "onError: 鲁班压缩出错");
                    }
                }).launch();    //启动压缩
    }