Android图片压缩以及优化实例

 private Bitmap compressPixel(String filePath){
  Bitmap bmp = null;
  BitmapFactory.Options options = new BitmapFactory.Options();
  //setting inSampleSize value allows to load a scaled down version of the original image
  options.inSampleSize = 2;

  //inJustDecodeBounds set to false to load the actual bitmap
  options.inJustDecodeBounds = false;
  options.inTempStorage = new byte[16 * 1024];
  try {
   //load the bitmap from its path
   bmp = BitmapFactory.decodeFile(filePath, options);
   if (bmp == null) {

    InputStream inputStream = null;
    try {
     inputStream = new FileInputStream(filePath);
     BitmapFactory.decodeStream(inputStream, null, options);
     inputStream.close();
    } catch (FileNotFoundException exception) {
     exception.printStackTrace();
    } catch (IOException exception) {
     exception.printStackTrace();
    }
   }
  } catch (OutOfMemoryError exception) {
   exception.printStackTrace();
  }finally {
   return bmp;
  }
 }

Matrix scaleMatrix = new Matrix();
  scaleMatrix.setScale(ratioX, ratioY, 0, 0);

  Canvas canvas = new Canvas(scaledBitmap);
  canvas.setMatrix(scaleMatrix);
  canvas.drawBitmap(bmp, 0, 0, new Paint(Paint.FILTER_BITMAP_FLAG));

//进行有损压缩
ByteArrayOutputStream baos = new ByteArrayOutputStream();
int options_ = 100;
actualOutBitmap.compress(Bitmap.CompressFormat.JPEG, options_, baos);
//质量压缩方法，把压缩后的数据存放到baos中 (100表示不压缩，0表示压缩到最小)
int baosLength = baos.toByteArray().length;
while (baosLength / 1024 > maxFileSize)
 {
//循环判断如果压缩后图片是否大于maxMemmorrySize,大于继续压缩 
baos.reset();
//重置baos即让下一次的写入覆盖之前的内容
 options_ = Math.max(0, options_ - 10);//图片质量每次减少10
 actualOutBitmap.compress(Bitmap.CompressFormat.JPEG, options_, baos);
//将压缩后的图片保存到baos中 
baosLength = baos.toByteArray().length;
 if (options_ == 0)//如果图片的质量已降到最低则，不再进行压缩 
break;
}