Xamarin.android compress the pictures and upload them to webservices

With the mobile phone camera more and more pixels, resulting in a picture like the capacity of more and more large, if uploading more than one picture is not compressed, quality processing is prone to oom memory leak problem.

Recently made a project to upload multiple photos to webservices, but the project deployment will appear flashback phenomenon, and later debugging found that the picture is not compressed, a picture size of 2M, however WebServices can not pick up multiple large pictures, so need to change the configuration file, Here I change to 40M.

  <system.web> "     40960 " usefullyqualifiedredirecturl="true "/>  </system.web>

　　Change here to find the upload picture or there is a problem, and then after a step-by-step debugging found that the local image converted to bitmap did not empty, and then kept in memory, resulting in memory leaks. Just empty the converted bitmap.

        /// <summary>        ///convert a picture into a string stream/// </summary>        /// <param name= "File_path" >file name (without file://)</param>        /// <returns></returns>         Public Static stringImagetostring (stringFile_path) {            //image path to upload//string uploadfile = File_path; //Convert to file//System.IO.FileInfo imgfile = new System.IO.FileInfo (uploadfile);            ////File converted to bytes            //byte[] Imgbyte = new Byte[imgfile.length];            //////Read the file            //System.IO.FileStream Imgstream = Imgfile.openread ();            //////writes a file to a byte array            //imgstream.read (imgbyte, 0, Convert.ToInt32 (imgfile.length));            //////byte array converted to String type            //string by = Convert.tobase64string (imgbyte);            ////file name after uploading to the server////fileup.updatefile (Imgbyte, Guid.NewGuid () + ". png");            //return imgbyte; Bitmap Bitmap= Bitmapfactory.decodefile (File_path);//convert picture files to bitmap format:/storage/emulated/0/dcim/camera/img_20180425_105725.jpg            stringBitstring =bitmaptostring (bitmap); Bitmap=NULL;//Be sure to clear it, or it will cause an oom problemGC.            Collect (); returnbitstring; }         /// <summary>        ///Image Zoom Processing/// </summary>        /// <param name= "Bgimage" >Bitmap File</param>        /// <param name= "Newwidth" >New picture Width</param>        /// <param name= "Newheight" >New picture Height</param>        /// <returns></returns>         Public StaticBitmap zoomimage (Bitmap bgimage,DoubleNewwidth,Doublenewheight) {            //get the width and height of this picture            floatwidth =Bgimage.            Width; floatHeight =Bgimage.            Height; //Create a Matrix object for manipulating picturesMatrix Matrix =NewMatrix (); //calculate the wide and high zoom rate            floatScaleWidth = ((float) newwidth)/width; floatScaleHeight = ((float) newheight)/height; //Zoom Picture ActionMatrix.            Postscale (ScaleWidth, ScaleHeight); Bitmap Bitmap= Bitmap.createbitmap (Bgimage,0,0, (int) width, (int) Height, matrix,true); returnbitmap; }        Static  stringbitmaptostring (Bitmap Bitmap) {Bitmap bit= Zoomimage (Bitmap, -, +);//Small Map//Mass Compression//MemoryStream stream = new MemoryStream (); //bit.compress (Bitmap.CompressFormat.Jpeg, (), stream); //byte[] BitmapData = stream.            ToArray (); //Bitmap map = Bitmapfactory.decodebytearray (bitmapData, 0, bitmapdata.length); //Btn_imagetwo.            Setimagebitmap (map); //Bitmap im = Zoomimage (Bitmap, n, +);//Big PictureMemoryStream Big_stream =NewMemoryStream (); Bit.compress (Bitmap.CompressFormat.Jpeg, the, Big_stream); byte[] Big_bitmapdata =Big_stream.            ToArray (); returnconvert.tobase64string (Big_bitmapdata); }        

WebServices Accept to save the picture:

PrivateString ImagePath ="/handlerimages/"; /// <summary>        ///Upload Image/// </summary>        /// <param name= "Content" >Picture character Stream</param>        /// <param name= "Pathandname" >Picture name</param>        /// <returns></returns>[WebMethod] Public BOOLUpdatefile (stringContentstringpathandname) {            //Save Picture Path            stringFilePath =Server.MapPath (ImagePath); //determine if a path exists            if(!directory.exists (FilePath)) {                //Create Pathdirectory.createdirectory (FilePath); }            stringSavefilepath =Path.Combine (FilePath, pathandname); byte[] filebytes; Try{filebytes=convert.frombase64string (content); MemoryStream MemoryStream=NewMemoryStream (filebytes);//1. Define and instantiate a memory stream to hold the byte array submitted. FileStream fileUpload =NewFileStream (Savefilepath, FileMode.Create);///2. Define the actual file object and save the uploaded file. Memorystream.writeto (FileUpload);///3. Write the data in the memory stream to a physical fileMemorystream.close ();                Fileupload.close (); FileUpload=NULL; MemoryStream=NULL; return true; }            Catch            {                return false; }        }

Call WebServices upload Image:

New
Service. Updatefile (Imagetobyte ("/storage/emulated/0/dcim/camera/img_20180425_105725.jpg" " . jpg ");

Xamarin.android compress the pictures and upload them to webservices