I have implemented a UIActivityViewController, for sharing some information. In this case I have a question: Is it possible to make a different text between the facebook sharing/twitter sharing/ or mail sharing? That the text which is set is different from the others...
A good UIActivityViewController tutorial would be very useful.
My code at the time is, for displaying text and image:
NSString *text = #"Lime Cat";
UIImage *image = [UIImage imageNamed:#"MyApp Icon 512x512.png"];
NSArray *items = [NSArray arrayWithObjects:text,image , nil];
But how can I manage it that the NSString is just for the mail, and make a seperate NSString for the facebook share option?
Any suggestions?
Thanks.
you can go to the link bellow, there is a tutorial that can help you :
https://www.albertopasca.it/whiletrue/objective-c-custom-uiactivityviewcontroller-icons-and-text/
You can have your class conform to the UIActivityItemSource protocol and implement activityViewController:itemForActivityType:. The activityType will be FB, Twitter, Messages app, etc, so you can do a switch on it and return a different object based on the activity.
-(void)ShareImageandText:(UIButton *)sender
{
NSString *texttoshare =#"http://qrs.ly/l851gh4";
UIImage *image = [UIImage imageNamed:#"default"];
NSString *noteStr = [NSString stringWithFormat:#"Please follow this link below to install the Freedom.desi application on your IPhone. %#",texttoshare];
NSURL *url = [NSURL URLWithString:texttoshare];
NSArray *activityItems = #[noteStr,image];
NSLog(#"this %#",activityItems);
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone) {
UIActivityViewController *activityVC = [[UIActivityViewController alloc] initWithActivityItems:#[noteStr,image] applicationActivities:nil];
activityVC.excludedActivityTypes = #[UIActivityTypeAssignToContact, UIActivityTypePrint];
[self shareText:noteStr
andImage:image andUrl:nil];
[self presentViewController:activityVC animated:TRUE completion:nil];
}
//if iPad
else {
// Change Rect to position Popover
UIActivityViewController *activityVC = [[UIActivityViewController alloc] initWithActivityItems:#[noteStr, url] applicationActivities:nil];
activityVC.excludedActivityTypes = #[UIActivityTypeAssignToContact, UIActivityTypePrint];
[self shareText:noteStr
andImage:image andUrl:nil];
UIPopoverController *popup = [[UIPopoverController alloc] initWithContentViewController:activityVC];
[popup presentPopoverFromRect:CGRectMake(self.view.frame.size.width/2, self.view.frame.size.height/4, 0, 0)inView:self.view permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];
}
}
I want to fetch JSON data asynchronously. The data is set up in a way that one request will bring only 8 records. I need to send the requests repeatedly until the response becomes empty or returns less than 8 records.
Currently, I have these methods in myviewcontroller.m class:
(void)myCallback:(id)sender {
MyDataRequest *objMyDataRequest = [[[MyDataRequest alloc] init] autorelease];
objMyDataRequest.myRequiredVariableToGetAuthTokenDataResponse = classOfMyCallBack.someVariable;
// Initiate getAuthToken request
[objWishListRequest initiateGetAuthTokenRequest:self requestSelector:#selector(getAuthTokenDataResponse:)];
}
Now here is the definition of getAuthTokenDataResponse:
(void) getAuthTokenDataResponse:(NSData *)data {
NSString *stringResponse = [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding];
SBJsonParser *parser=[[SBJsonParser alloc]init];
NSDictionary *objDictionaryForStringResponse = [parser objectWithString:stringResponse];
[stringResponse release];
[parser release];
MyListRequest *objMyListRequest = [[[MyListRequest alloc] init] autorelease];
objMyListRequest.myRequiredValueToGetMyDataResponse = [objDictionaryForStringResponse objectForKey:#"Data"];
// Initiate GetMyDataResponse request
[objMyListRequest initiateGetMyDataRequest:self requestSelector:#selector(getMyDataResponse:)];
}
(void) getMyDataResponse:(NSData *)data {
NSString *stringResponse = [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding];
SBJsonParser *parser=[[SBJsonParser alloc]init];
NSDictionary *objGetMyDataRootDictionary = [parser objectWithString:stringResponse];
[stringResponse release];
[parser release];
NSDictionary *dataElements=[objGetMyDataRootDictionary objectForKey:#"Data"];
Wish *objMyData;
for (NSDictionary* objGetMyDataRootDictionary in dataElements) {
objMyData = [[Wish alloc]init];
//add different elements from dataElements into member variables of object objWish
[self.myDataArray addObject:objMyData];
[objMyData release];
}
[self.myDataTableView reloadData];
}
This method lies in MyDataRequest class:
(void)initiateGetMyDataRequest:(id)requestDelegate requestSelector:(SEL)requestSelector{
// Set the delegate and selector
self.delegate = requestDelegate;
self.callback = requestSelector;
NSString* unescapedUrlString = [NSString stringWithFormat:#"http://test.mytesturl.com/core.svc/alldata/My/get/All/?token=%#&search=&page=1",myRequiredtokenparameter];
[self request:url];
}
I need to send multiple requests to the same url (with different parameter value i.e. value of page number) to fetch the results. How may I achieve it given the above scenario? The calls must be asynchronous.
How should I make the actual flow between all these calls? How may I get the data of "all the pages" asynchronously?
I think you are looking for a operation queue. I use ASIHTTPRequests in my apps and they work.
If you want to use this library, here's the link how to use it: Show UIActivityIndicatorView when loading NSString from Web
I have a table view and I'd like to download an icon image (100x75) to each row asynchronously. I've followed many tutorials so far but I can't seem to figure it out. How should I do it?
Does anyone recommend just doing it using the standard NSURLConnection API or should I use one of those classes/libraries that are available online to do so? If so, what do you recommend?
Of course, I need it to be fast, efficient and does not leak. I also don't want the downloading to affect the scrolling.
Thank you!
Two options I can think of:
(1) Use ASIHTTPRequest.
(2) A custom implementation that spawns a thread in which you load the image using a combination of NSURL/NSData. Once the image is loaded, send it to a method on the main UI thread using performSelectorOnMainThread:withObject:.
NSThread *t = [[NSThread alloc] initWithTarget:self selector:#selector(loadImage:) object:nil];
[t start];
[t release];
-(void) updateImage:(id) obj {
// do whatever you need to do
}
-(void) loadImage:(id) obj {
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
NSURL *url = [NSURL URLWithString:#"imageurl"];
NSData *imageData = [[NSData alloc]initWithContentsOfURL:url];
UIImage *image = [UIImage imageWithData:imageData];
[imageData release];
[self performSelectorOnMainThread:#selector(updateImage:) withObject:data waitUntilDone:YES];
[pool release];
}
I'd recommend you using ASIHTTPRequest. Its simple and pretty fast.
Here is a link to the documentation - ASIHTTPRequest
EDIT
You need to download images for visible cells only.
Heres a sample:
- (void)loadContentForVisibleCells
{
NSArray *cells = [self.tableView visibleCells];
[cells retain];
for (int i = 0; i < [cells count]; i++)
{
...
// Request should be here
...
}
[cells release];
}
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate;
{
if (!decelerate)
{
[self loadContentForVisibleCells];
}
}
Anyway u'll need to code a lot to make things work good and fast.
I have a method that asynchronously downloads images. If the images are related to an array of objects (a common use-case in the app I'm building), I want to cache them. The idea is, I pass in an index number (based on the indexPath.row of the table I'm making by way through), and I stash the image in a static NSMutableArray, keyed on the row of the table I'm dealing with.
Thusly:
#implementation ImageDownloader
...
#synthesize cacheIndex;
static NSMutableArray *imageCache;
-(void)startDownloadWithImageView:(UIImageView *)imageView andImageURL:(NSURL *)url withCacheIndex:(NSInteger)index
{
self.theImageView = imageView;
self.cacheIndex = index;
NSLog(#"Called to download %# for imageview %#", url, self.theImageView);
if ([imageCache objectAtIndex:index]) {
NSLog(#"We have this image cached--using that instead");
self.theImageView.image = [imageCache objectAtIndex:index];
return;
}
self.activeDownload = [NSMutableData data];
NSURLConnection *conn = [[NSURLConnection alloc]
initWithRequest:[NSURLRequest requestWithURL:url] delegate:self];
self.imageConnection = conn;
[conn release];
}
//build up the incoming data in self.activeDownload with calls to didReceiveData...
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSLog(#"Finished downloading.");
UIImage *image = [[UIImage alloc] initWithData:self.activeDownload];
self.theImageView.image = image;
NSLog(#"Caching %# for %d", self.theImageView.image, self.cacheIndex);
[imageCache insertObject:image atIndex:self.cacheIndex];
NSLog(#"Cache now has %d items", [imageCache count]);
[image release];
}
My index is getting through okay, I can see that by my NSLog output. But even after my insertObject: atIndex: call, [imageCache count] never leaves zero.
This is my first foray into static variables, so I presume I'm doing something wrong.
(The above code is heavily pruned to show only the main thing of what's going on, so bear that in mind as you look at it.)
You seem to never initialize the imageCache and probably got lucky with it having the value 0. The initialization would best be done in the class' initialization, e.g.:
#implementation ImageDownloader
// ...
+(void)initialize {
imageCache = [[NSMutableArray alloc] init];
}
// ...
It's well known that UIImagePickerController doesn't return the metadata of the photo after selection. However, a couple of apps in the app store (Mobile Fotos, PixelPipe) seem to be able to read the original files and the EXIF data stored within them, enabling the app to extract the geodata from the selected photo.
They seem to do this by reading the original file from the /private/var/mobile/Media/DCIM/100APPLE/ folder and running it through an EXIF library.
However, I can't work out a way of matching a photo returned from the UIImagePickerController to a file on disk. I've explored file sizes, but the original file is a JPEG, whilst the returned image is a raw UIImage, making it impossible to know the file size of the image that was selected.
I'm considering making a table of hashes and matching against the first x pixels of each image. This seems a bit over the top though, and probably quite slow.
Any suggestions?
Have you took a look at this exif iPhone library?
http://code.google.com/p/iphone-exif/
Gonna try it on my side. I'd like to get the GPS (geotags) coordinates from the picture that has been taken with the UIImagePickerController :/
After a deeper look, this library seems to take NSData info as an input and the UIImagePickerController returns a UIImage after taking a snapshot. In theory, if we use the selected from the UIkit category for UIImage
NSData * UIImageJPEGRepresentation (
UIImage *image,
CGFloat compressionQuality
);
Then we can convert the UIImage into a NSData instance and then use it with the iPhone exif library.
UPDATE:
I gave a test to the library mentioned above and it seems to work. However because of my limited knwoledge about the EXIF format and the lack of high level API in the library, I don't manage to get the values for the EXIF tags.
Here's my code in case any of you can go further :
#import "EXFJpeg.h"
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)image editingInfo:(NSDictionary *)editingInfo {
NSLog(#"image picked %# with info %#", image, editingInfo);
NSData* jpegData = UIImageJPEGRepresentation (image,0.5);
EXFJpeg* jpegScanner = [[EXFJpeg alloc] init];
[jpegScanner scanImageData: jpegData];
EXFMetaData* exifData = jpegScanner.exifMetaData;
EXFJFIF* jfif = jpegScanner.jfif;
EXFTag* tagDefinition = [exifData tagDefinition: [NSNumber numberWithInt:EXIF_DateTime]];
//EXFTag* latitudeDef = [exifData tagDefinition: [NSNumber numberWithInt:EXIF_GPSLatitude]];
//EXFTag* longitudeDef = [exifData tagDefinition: [NSNumber numberWithInt:EXIF_GPSLongitude]];
id latitudeValue = [exifData tagValue:[NSNumber numberWithInt:EXIF_GPSLatitude]];
id longitudeValue = [exifData tagValue:[NSNumber numberWithInt:EXIF_GPSLongitude]];
id datetime = [exifData tagValue:[NSNumber numberWithInt:EXIF_DateTime]];
id t = [exifData tagValue:[NSNumber numberWithInt:EXIF_Model]];
....
....
The retrieving of tags definition is OK, but all tag values returns nil :(
In case you want to give a try to the library, you need to define a global variable to get it running (as explained in the doc but hum.. :/)
BOOL gLogging = FALSE;
UPDATE 2
Answer here : iPhone - access location information from a photo
A UIImage does not encapsulate the meta information, so we're stuck : for sure, no EXIF info will be given through this interface.
FINAL UPDATE
Ok I managed to get it working, at least to geotag properly pictures returned by the picker.
Before triggering the UIImagePickerController, it's up to you to use the CLLocationManager to retrieve the current CLocation
Once you have it, you can use this method that uses exif-iPhone library to geotag the UIImage from the CLLocation :
-(NSData*) geotagImage:(UIImage*)image withLocation:(CLLocation*)imageLocation {
NSData* jpegData = UIImageJPEGRepresentation(image, 0.8);
EXFJpeg* jpegScanner = [[EXFJpeg alloc] init];
[jpegScanner scanImageData: jpegData];
EXFMetaData* exifMetaData = jpegScanner.exifMetaData;
// end of helper methods
// adding GPS data to the Exif object
NSMutableArray* locArray = [self createLocArray:imageLocation.coordinate.latitude];
EXFGPSLoc* gpsLoc = [[EXFGPSLoc alloc] init];
[self populateGPS: gpsLoc :locArray];
[exifMetaData addTagValue:gpsLoc forKey:[NSNumber numberWithInt:EXIF_GPSLatitude] ];
[gpsLoc release];
[locArray release];
locArray = [self createLocArray:imageLocation.coordinate.longitude];
gpsLoc = [[EXFGPSLoc alloc] init];
[self populateGPS: gpsLoc :locArray];
[exifMetaData addTagValue:gpsLoc forKey:[NSNumber numberWithInt:EXIF_GPSLongitude] ];
[gpsLoc release];
[locArray release];
NSString* ref;
if (imageLocation.coordinate.latitude <0.0)
ref = #"S";
else
ref =#"N";
[exifMetaData addTagValue: ref forKey:[NSNumber numberWithInt:EXIF_GPSLatitudeRef] ];
if (imageLocation.coordinate.longitude <0.0)
ref = #"W";
else
ref =#"E";
[exifMetaData addTagValue: ref forKey:[NSNumber numberWithInt:EXIF_GPSLongitudeRef] ];
NSMutableData* taggedJpegData = [[NSMutableData alloc] init];
[jpegScanner populateImageData:taggedJpegData];
[jpegScanner release];
return [taggedJpegData autorelease];
}
// Helper methods for location conversion
-(NSMutableArray*) createLocArray:(double) val{
val = fabs(val);
NSMutableArray* array = [[NSMutableArray alloc] init];
double deg = (int)val;
[array addObject:[NSNumber numberWithDouble:deg]];
val = val - deg;
val = val*60;
double minutes = (int) val;
[array addObject:[NSNumber numberWithDouble:minutes]];
val = val - minutes;
val = val*60;
double seconds = val;
[array addObject:[NSNumber numberWithDouble:seconds]];
return array;
}
-(void) populateGPS:(EXFGPSLoc* ) gpsLoc :(NSArray*) locArray{
long numDenumArray[2];
long* arrPtr = numDenumArray;
[EXFUtils convertRationalToFraction:&arrPtr :[locArray objectAtIndex:0]];
EXFraction* fract = [[EXFraction alloc] initWith:numDenumArray[0]:numDenumArray[1]];
gpsLoc.degrees = fract;
[fract release];
[EXFUtils convertRationalToFraction:&arrPtr :[locArray objectAtIndex:1]];
fract = [[EXFraction alloc] initWith:numDenumArray[0] :numDenumArray[1]];
gpsLoc.minutes = fract;
[fract release];
[EXFUtils convertRationalToFraction:&arrPtr :[locArray objectAtIndex:2]];
fract = [[EXFraction alloc] initWith:numDenumArray[0] :numDenumArray[1]];
gpsLoc.seconds = fract;
[fract release];
}
This works with iOS5 (beta 4) and the camera roll (you need type defs for the blocks in the .h):
-(void) imagePickerController:(UIImagePickerController *)picker
didFinishPickingMediaWithInfo:(NSDictionary *)info
{
NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];
if ([mediaType isEqualToString:(NSString*)kUTTypeImage]) {
NSURL *url = [info objectForKey:UIImagePickerControllerReferenceURL];
if (url) {
ALAssetsLibraryAssetForURLResultBlock resultblock = ^(ALAsset *myasset) {
CLLocation *location = [myasset valueForProperty:ALAssetPropertyLocation];
// location contains lat/long, timestamp, etc
// extracting the image is more tricky and 5.x beta ALAssetRepresentation has bugs!
};
ALAssetsLibraryAccessFailureBlock failureblock = ^(NSError *myerror) {
NSLog(#"cant get image - %#", [myerror localizedDescription]);
};
ALAssetsLibrary *assetsLib = [[ALAssetsLibrary alloc] init];
[assetsLib assetForURL:url resultBlock:resultblock failureBlock:failureblock];
}
}
There is a way in iOS 8
Without using any 3rd party EXIF library.
#import <Photos/Photos.h>
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
NSURL *url = [info objectForKey:UIImagePickerControllerReferenceURL];
PHFetchResult *fetchResult = [PHAsset fetchAssetsWithALAssetURLs:#[url] options:nil];
PHAsset *asset = fetchResult.firstObject;
//All you need is
//asset.location.coordinate.latitude
//asset.location.coordinate.longitude
//Other useful properties of PHAsset
//asset.favorite
//asset.modificationDate
//asset.creationDate
}
Apple has added an Image I/O Framework in iOS4 which can be used to read EXIF data from pictures. I don't know if the UIImagePickerController returns a picture with the EXIF data embedded though.
Edit: In iOS4 you can fetch the EXIF data by grabbing the value of the UIImagePickerControllerMediaMetadata key in the info dictionary which is passed to the UIImagePickerControllerDelegate delegate.
I had a similar question where I wanted just the date a picture was taken and none of the above appear to solve my problem in a simple way (e.g. no external libraries), so here is all of the data I could find which you can extract from an image after selecting it with the picker:
// Inside whatever implements UIImagePickerControllerDelegate
#import AssetsLibrary;
// ... your other code here ...
#implementation MYImagePickerDelegate
- (void)imagePickerController:(UIImagePickerController *)picker
didFinishPickingMediaWithInfo:(NSDictionary *)info
{
NSString *mediaType = info[UIImagePickerControllerMediaType];
UIImage *originalImage = info[UIImagePickerControllerOriginalImage];
UIImage *editedImage = info[UIImagePickerControllerEditedImage];
NSValue *cropRect = info[UIImagePickerControllerCropRect];
NSURL *mediaUrl = info[UIImagePickerControllerMediaURL];
NSURL *referenceUrl = info[UIImagePickerControllerReferenceURL];
NSDictionary *mediaMetadata = info[UIImagePickerControllerMediaMetadata];
NSLog(#"mediaType=%#", mediaType);
NSLog(#"originalImage=%#", originalImage);
NSLog(#"editedImage=%#", editedImage);
NSLog(#"cropRect=%#", cropRect);
NSLog(#"mediaUrl=%#", mediaUrl);
NSLog(#"referenceUrl=%#", referenceUrl);
NSLog(#"mediaMetadata=%#", mediaMetadata);
if (!referenceUrl) {
NSLog(#"Media did not have reference URL.");
} else {
ALAssetsLibrary *assetsLib = [[ALAssetsLibrary alloc] init];
[assetsLib assetForURL:referenceUrl
resultBlock:^(ALAsset *asset) {
NSString *type =
[asset valueForProperty:ALAssetPropertyType];
CLLocation *location =
[asset valueForProperty:ALAssetPropertyLocation];
NSNumber *duration =
[asset valueForProperty:ALAssetPropertyDuration];
NSNumber *orientation =
[asset valueForProperty:ALAssetPropertyOrientation];
NSDate *date =
[asset valueForProperty:ALAssetPropertyDate];
NSArray *representations =
[asset valueForProperty:ALAssetPropertyRepresentations];
NSDictionary *urls =
[asset valueForProperty:ALAssetPropertyURLs];
NSURL *assetUrl =
[asset valueForProperty:ALAssetPropertyAssetURL];
NSLog(#"type=%#", type);
NSLog(#"location=%#", location);
NSLog(#"duration=%#", duration);
NSLog(#"assetUrl=%#", assetUrl);
NSLog(#"orientation=%#", orientation);
NSLog(#"date=%#", date);
NSLog(#"representations=%#", representations);
NSLog(#"urls=%#", urls);
}
failureBlock:^(NSError *error) {
NSLog(#"Failed to get asset: %#", error);
}];
}
[picker dismissViewControllerAnimated:YES
completion:nil];
}
#end
So when you select an image, you get output that looks like this (including date!):
mediaType=public.image
originalImage=<UIImage: 0x7fb38e00e870> size {1280, 850} orientation 0 scale 1.000000
editedImage=<UIImage: 0x7fb38e09e1e0> size {640, 424} orientation 0 scale 1.000000
cropRect=NSRect: {{0, 0}, {1280, 848}}
mediaUrl=(null)
referenceUrl=assets-library://asset/asset.JPG?id=AC072879-DA36-4A56-8A04-4D467C878877&ext=JPG
mediaMetadata=(null)
type=ALAssetTypePhoto
location=(null)
duration=ALErrorInvalidProperty
assetUrl=assets-library://asset/asset.JPG?id=AC072879-DA36-4A56-8A04-4D467C878877&ext=JPG
orientation=0
date=2014-07-14 04:28:18 +0000
representations=(
"public.jpeg"
)
urls={
"public.jpeg" = "assets-library://asset/asset.JPG?id=AC072879-DA36-4A56-8A04-4D467C878877&ext=JPG";
}
Anyway, hopefully that saves someone else some time.
I spend a while working on this as well for an application I was contracted to build. Basically as the API currently stands it is not possible. The basic problem is the UIImage class STRIPS all EXIF data except for the orientation out. Also the function to save to the camera roll strips this data out. So basically the only way to grab and maintain any extra EXIF data is to save it in a private "camera roll" in your application. I have filed this bug with apple as well and emphasized the need to the app reviewer reps we've been in contact with. Hopefully someday they'll add it in.. Otherwise it makes having GEO tagging completely useless as it only works in the "stock" camera application.
NOTE Some applications on the app store hack around this. By, what I have found, directly accessing the camera roll and SAVING photos straight to it to save GEO data. However this only works with the camera roll/saved photos and NOT the rest of the photo library. The photos "synced" to your phone from your computer have all EXIF data except for orientation stripped.
I still can't understand why those applications were approved (heck they even DELETE from the camera roll) and our application which does none of that is still being held back.
For iOS 8 and later you can use Photos Framework.
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
let url = info[UIImagePickerControllerReferenceURL] as? URL
if url != nil {
let fetchResult = PHAsset.fetchAssets(withALAssetURLs: [url!], options: nil)
let asset = fetchResult.firstObject
print(asset?.location?.coordinate.latitude)
print(asset?.creationDate)
}
}
This is something that the public API does not provide, but could be useful to many people. Your primary recourse is to file a bug with Apple that describes what you need (and it can be helpful to explain why you need it as well). Hopefully your request could make it into a future release.
After filing a bug, you could also use one of the Developer Technical Support (DTS) incidents that came with your iPhone Developer Program membership. If there is a public way to do this, an Apple engineer will know. Otherwise, it may at least help get your plight a bit more attention within the mothership. Best of luck!
Use the UIImagePickerControllerMediaURL dictionary key to get the file URL to the original file. Despite what the documentation says, you can get the file URL for photos and not only movies.
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
// Try to get the original file.
NSURL *originalFile = [info objectForKey:UIImagePickerControllerMediaURL];
if (originalFile) {
NSData *fileData = [NSData dataWithContentsOfURL:originalFile];
}
}
You might be able to hash the image data returned by the UIImagePickerController and each of the images in the directory and compare them.
Just a thought, but have you tried TTPhotoViewController in the Three20 project on GitHub?
That provides an image picker that can read from multiple sources. You may be able to use it as an alternative to UIImagePickerController, or the source might give you a clue how to work out how to get the info you need.
Is there a specific reason you want to extract the location data from the image? An alternative could be to get the location separately using the CoreLocation framework. If it's only the geodata you need, this might save you some headaches.
it seems that photo attained by UIImagePickerControllerMediaURL don't have exif tags at all
In order to get this metadata you'll have to use the lower level framework AVFoundation.
Take a look at Apple's Squarecam example (http://developer.apple.com/library/ios/#samplecode/SquareCam/Introduction/Intro.html)
Find the method below and add the line, I've added to the code. The metadata dictionary returned also contains a diagnostics NSDictionary object.
- (BOOL)writeCGImageToCameraRoll:(CGImageRef)cgImage withMetadata:(NSDictionary *)metadata
{
NSDictionary *Exif = [metadata objectForKey:#"Exif"]; // Add this line
}
I'm using this for camera roll images
-(CLLocation*)locationFromAsset:(ALAsset*)asset
{
if (!asset)
return nil;
NSDictionary* pickedImageMetadata = [[asset defaultRepresentation] metadata];
NSDictionary* gpsInfo = [pickedImageMetadata objectForKey:(__bridge NSString *)kCGImagePropertyGPSDictionary];
if (gpsInfo){
NSNumber* nLat = [gpsInfo objectForKey:(__bridge NSString *)kCGImagePropertyGPSLatitude];
NSNumber* nLng = [gpsInfo objectForKey:(__bridge NSString *)kCGImagePropertyGPSLongitude];
if (nLat && nLng)
return [[CLLocation alloc]initWithLatitude:[nLat doubleValue] longitude:[nLng doubleValue]];
}
return nil;
}
-(void) imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
//UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];
NSURL *assetURL = [info objectForKey:UIImagePickerControllerReferenceURL];
// create the asset library in the init method of your custom object or view controller
//self.library = [[ALAssetsLibrary alloc] init];
//
[self.library assetForURL:assetURL resultBlock:^(ALAsset *asset) {
// try to retrieve gps metadata coordinates
CLLocation* myLocation = [self locationFromAsset:asset];
// Do your stuff....
} failureBlock:^(NSError *error) {
NSLog(#"Failed to get asset from library");
}];
}
It works obviously if the image contains gps meta informations
Hope it helps
This is in Swift 3 if you still want support for iOS 8:
import AssetsLibrary
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
if picker.sourceType == UIImagePickerControllerSourceType.photoLibrary,
let url = info[UIImagePickerControllerReferenceURL] as? URL {
let assetLibrary = ALAssetsLibrary()
assetLibrary.asset(for: url, resultBlock: { (asset) in
if let asset = asset {
let assetRep: ALAssetRepresentation = asset.defaultRepresentation()
let metaData: NSDictionary = assetRep.metadata() as NSDictionary
print(metaData)
}
}, failureBlock: { (error) in
print(error!)
})
}
}
For iOS 10 - Swift 3
The picker's callback has an info dict where there is a key with metadata: UIImagePickerControllerMediaMetadata
The naughty way to do this is to traverse the UIImagePickerViewController's views and pick out the selected image in the delegate callback.
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
id thumbnailView = [[[[[[[[[[picker.view subviews]
objectAtIndex:0] subviews]
objectAtIndex:0] subviews]
objectAtIndex:0] subviews]
objectAtIndex:0] subviews]
objectAtIndex:0];
NSString *fullSizePath = [[[thumbnailView selectedPhoto] fileGroup] pathForFullSizeImage];
NSString *thumbnailPath = [[[thumbnailView selectedPhoto] fileGroup] pathForThumbnailFile];
NSLog(#"%# and %#", fullSizePath, thumbnailPath);
}
That will give you the path to the full size image, which you can then open with an EXIF library of your choice.
But, this calls a Private API and these method names will be detected by Apple if you submit this app. So don't do this, OK?