android 将图片压缩到指定的大小的示例

  /**  * 根据分辨率压缩图片比例  *  * @param imgPath  * @param w  * @param h  * @return  */ private static Bitmap compressByResolution(String imgPath, int w, int h) {  BitmapFactory.Options opts = new BitmapFactory.Options();  opts.inJustDecodeBounds = true;  BitmapFactory.decodeFile(imgPath, opts);  int width = opts.outWidth;  int height = opts.outHeight;  int widthScale = width / w;  int heightScale = height / h;  int scale;  if (widthScale < heightScale) { //保留压缩比例小的   scale = widthScale;  } else {   scale = heightScale;  }  if (scale < 1) {   scale = 1;  }  Log.i(TAG,"图片分辨率压缩比例：" + scale);  opts.inSampleSize = scale;  opts.inJustDecodeBounds = false;  Bitmap bitmap = BitmapFactory.decodeFile(imgPath, opts);  return bitmap; }

 /**  * 根据分辨率压缩  *  * @param srcPath 图片路径  * @param ImageSize 图片大小 单位kb  * @return  */ public static boolean compressBitmap(String srcPath, int ImageSize, String savePath) {  int subtract;  Log.i(TAG, "图片处理开始..");  Bitmap bitmap = compressByResolution(srcPath, 1024, 720); //分辨率压缩  if (bitmap == null) {   Log.i(TAG, "bitmap 为空");   return false;  }  ByteArrayOutputStream baos = new ByteArrayOutputStream();  int options = 100;  bitmap.compress(Bitmap.CompressFormat.JPEG, options, baos);//质量压缩方法，这里100表示不压缩，把压缩后的数据存放到baos中  Log.i(TAG, "图片分辨率压缩后：" + baos.toByteArray().length / 1024 + "KB");  while (baos.toByteArray().length > ImageSize * 1024) { //循环判断如果压缩后图片是否大于ImageSize kb,大于继续压缩   subtract = setSubstractSize(baos.toByteArray().length / 1024);   baos.reset();//重置baos即清空baos   options -= subtract;//每次都减少10   bitmap.compress(Bitmap.CompressFormat.JPEG, options, baos);//这里压缩options%，把压缩后的数据存放到baos中   Log.i(TAG, "图片压缩后：" + baos.toByteArray().length / 1024 + "KB");  }  Log.i(TAG, "图片处理完成!" + baos.toByteArray().length / 1024 + "KB");  try {   FileOutputStream fos = new FileOutputStream(new File(savePath));//将压缩后的图片保存的本地上指定路径中   fos.write(baos.toByteArray());   fos.flush();   fos.close();  } catch (Exception e) {   e.printStackTrace();  }  if (bitmap != null) {   bitmap.recycle();  }  return true; //压缩成功返回ture }

 /**  * 根据图片的大小设置压缩的比例，提高速度  *  * @param imageMB  * @return  */ private static int setSubstractSize(int imageMB) {  if (imageMB > 1000) {   return 60;  } else if (imageMB > 750) {   return 40;  } else if (imageMB > 500) {   return 20;  } else {   return 10;  } }