ios - How to save selected images from gallery through ALAssetsLibrary to document directory of app -

i have fetched images gallery collection view through alassetslibrary . , have done successfully.

now, want save selected image collection view document directory of app.

and selecting images code--

-(void)done { nsmutablearray *imagearray = [[nsmutablearray alloc] initwithcapacity:[selectedindexarr count]];  [selectedindexarr enumerateobjectsusingblock:^(id obj, nsuinteger idx, bool *stop) {     alassetslibrary *library = [[alassetslibrary alloc] init];     [library assetforurl:obj resultblock:^(alasset *asset) {         alassetrepresentation *representation = [asset defaultrepresentation];         uiimage *latestphoto = [uiimage imagewithcgimage:[representation fullscreenimage]];         [imagearray addobject:latestphoto];          if ([imagearray count]==[selectedindexarr count]) {             if ([self.delegate respondstoselector:@selector(ims_pickercontroller:didfinishpickingmediaitems:)]) {                 [self.delegate ims_pickercontroller:self didfinishpickingmediaitems:imagearray];             }         }         [self saveimagesfromlibrarytodocumentdirectory:imagearray];     } failureblock:^(nserror *error) {         nslog(@"failure picking media");     }]; }];  } 

and both of these working when trying save in document directory getting error @ line:

 nsstring *docpath = [nssearchpathfordirectoriesindomains(nsdocumentdirectory, nsuserdomainmask, yes)objectatindex:0];     nsstring* filename = [docpath stringbyappendingpathcomponent:[representation filename]]; 

terminating app due uncaught exception 'nsinvalidargumentexception', reason: '-[uiimage defaultrepresentation]: unrecognized selector sent instance 0x7afe6150' *** first throw call stack: (

0   corefoundation                      0x01a28946 __exceptionpreprocess + 182 1   libobjc.a.dylib                     0x016b1a97 objc_exception_throw + 44 2   corefoundation                      0x01a305c5 -[nsobject(nsobject) doesnotrecognizeselector:] + 277 3   corefoundation                      0x019793e7 ___forwarding___ + 1047 4   corefoundation                      0x01978fae _cf_forwarding_prep_0 + 14 5   moviemixture1                       0x00067571 -[imageselector saveimagesfromlibrarytodocumentdirectory:] + 177 6   moviemixture1                       0x000671b1 __21-[imageselector done]_block_invoke_2 + 513 7   assetslibrary                       0x0013a216 __56-[alassetslibrary assetforurl:resultblock:failureblock:]_block_invoke_2 + 215 8   libdispatch.dylib                   0x056eb30a _dispatch_call_block_and_release + 15 9   libdispatch.dylib                   0x0570be2f _dispatch_client_callout + 14 10  libdispatch.dylib                   0x056f290e _dispatch_main_queue_callback_4cf + 606 11  corefoundation                      0x0198295e __cfrunloop_is_servicing_the_main_dispatch_queue__ + 14 12  corefoundation                      0x01941760 __cfrunlooprun + 2256 13  corefoundation                      0x01940bcb cfrunlooprunspecific + 443 14  corefoundation                      0x019409fb cfrunloopruninmode + 123 15  graphicsservices                    0x04b3324f gseventrunmodal + 192 16  graphicsservices                    0x04b3308c gseventrun + 104 17  uikit                               0x020198b6 uiapplicationmain + 1526 18  moviemixture1                       0x0007dc4d main + 141 19  libdyld.dylib                       0x05737ac9 start + 1 

)

please me through this.

my code saving images:

-(void)saveimagesfromlibrarytodocumentdirectory:(nsarray *)imagearray { (int j=0; j<[imagearray count]; j++) {      alassetrepresentation *representation = [[imagearray objectatindex:j] defaultrepresentation];      nsstring *docpath = [nssearchpathfordirectoriesindomains(nsdocumentdirectory, nsuserdomainmask, yes)objectatindex:0];     nsstring* filename = [docpath stringbyappendingpathcomponent:[representation filename]];      [[nsfilemanager defaultmanager] createfileatpath:filename contents:nil attributes:nil];     nsoutputstream *outputstream = [nsoutputstream outputstreamtofileatpath:filename append:yes];     [outputstream open];      long long offset = 0;     long long bytesread = 0;      nserror *error;     uint8_t * buffer = malloc(131072);     while (offset<[representation size] && [outputstream hasspaceavailable]) {         bytesread = [representation getbytes:buffer fromoffset:offset length:131072 error:&error];         [outputstream write:buffer maxlength:bytesread];         offset = offset+bytesread;     }     [outputstream close];     free(buffer); } }