How to add multiple email attachments using UIActivityItemProvider - objective-c

Question

I'm working on an iOS app in which I want to add MULTIPLE attachments to an email using UIActivityItemProvider. I want to do it using UIActivityItemProvider because I do not want to incur the overhead of processing the record before I display the UIActivtyViewController to the user. If I pass in one image using an NSData or an NSURL object to the "url" element of the returned object, then the inline image shows fine. If I pass in an array of these objects then nothing shows up. I believe that passing an array will work if I use the ActivityItems parameter when initializing an NSActivityViewController, but again, I do not want to do this because I want to take advantage of the delayed processing available by using the UIActivityItemProvider. Below is my code
#implementation NoteRecordActivityProvider
- (id)initWithPlaceholderItem:(id)placeholderItem
{
//Initializes and returns a provider object with the specified placeholder data
return [super initWithPlaceholderItem:placeholderItem];
}
- (id)item
{
// //Generates and returns the actual data object
NSData *imageFile = [[NSData alloc]init];
NSString *imageFileName;
NSURL *url;
NSString* exportPath;
NSMutableArray* imageArray = [[NSMutableArray alloc]initWithCapacity:0];
NSInteger photoCount = self.noteRecord.photoCount;
for (NSInteger i = 0; i < photoCount; i+=1)
{
//Add File Attachment
PhotoObject *po = (PhotoObject*)[self.noteRecord photoObjects:i];
NSString *photoGUID = [(PhotoObject*)[self.noteRecord photoObjects:i]GUID];
imageFile = ImageDataReturningMethodHere;
imageFileName = [[NSArray arrayWithObjects:#"Image", [NSString stringWithFormat:#"%ld", (long)i], #".png", nil] componentsJoinedByString:#""];
exportPath = [[FileSystemProvider exportPath] stringByAppendingPathComponent:imageFileName];
[imageFile writeToFile:exportPath atomically:YES];
url = [NSURL fileURLWithPath:exportPath];
[imageArray addObject:url];
}
if ([self.activityType isEqualToString:UIActivityTypeMail])
return imageArray;
else
return nil;
}
- (id)activityViewControllerPlaceholderItem:(UIActivityViewController *)activityViewController
{
return #{#"body":#"", #"url":[[NSURL alloc]init]};
}
-(NSString *) activityViewController:(UIActivityViewController *)activityViewController subjectForActivityType:(NSString *)activityType {
return [NSString stringWithFormat:#"Attached Record: %#", self.noteRecord.title];
}
#end

Answer 1

I did find the answer to this question. First I created an PhotoAttachmentActivityProvider that had a property for the source document which contains the photo I wanted to attach, and an index to the attachment in that document. I'm pasting my code here which uses a custom document called a NoteRecord:
#interface EMailPhotoAttachmentItemProvider : UIActivityItemProvider
#property (nonatomic, readwrite) NSInteger photoIndex;
#property (nonatomic, strong) NoteRecord* noteRecord;
#end
Then when I am showing the UIActivityViewController I add 1 of these custom UIActivityItemProvider objects for each attachment:
for (NSInteger i = 0; i < self.noteRecord.photoCount; i++)
{
EMailPhotoAttachmentItemProvider* photoProvider = [[EMailPhotoAttachmentItemProvider alloc]initWithPlaceholderItem:#{#"body":textToShare, #"url":url}];
photoProvider.photoIndex = i;
photoProvider.noteRecord = self.noteRecord;
[activityProviders addObject:photoProvider];
}
//Initialize the ActivityViewController
UIActivityViewController *activityController = [[UIActivityViewController alloc] initWithActivityItems:activityProviders applicationActivities:applicationActivities];
Then in the custom UIActivityItemProvider I check for whether I'm processing a EMAIL, and then I create a URL for the image using the document and image index provided:
#import "EMailPhotoAttachmentItemProvider.h"
#import "MiscUtilities.h"
#import "FileSystemProvider.h"
#implementation EMailPhotoAttachmentItemProvider
- (id)initWithPlaceholderItem:(id)placeholderItem
{
//Initializes and returns a provider object with the specified placeholder data
return [super initWithPlaceholderItem:placeholderItem];
}
- (id)item
{
if ([self.activityType isEqualToString:UIActivityTypeMail])
{
// Code here gets the image file from the NoteRecord at the PhotoIndex provided to
// the UIActivityItemProvider at the imageIndex, creates a URL for that image and returns it here.
// Your implementation will vary
PhotoObject *po = (PhotoObject*)[self.noteRecord photoObjects:self.photoIndex];
NSString *photoGUID = [(PhotoObject*)[self.noteRecord photoObjects:self.photoIndex]GUID];
NSData *imageFile = [[[MiscUtilities getApplicationDelegate]imageProvider]imageDataWithCaptionFromGUID:photoGUID caption:po.caption maxResolution:600];
NSString *imageFileName = [[NSArray arrayWithObjects:#"Image", [NSString stringWithFormat:#"%ld", (long)self.photoIndex], #".png", nil] componentsJoinedByString:#""];
imageFileName = [[FileSystemProvider exportPath] stringByAppendingPathComponent:imageFileName];
[imageFile writeToFile:imageFileName atomically:YES];
NSURL *url = [NSURL fileURLWithPath:imageFileName];
return url;
}
else
{
return nil;
};
}
- (id)activityViewControllerPlaceholderItem:(UIActivityViewController *)activityViewController
{
NSString* defaultImagePath = [[FileSystemProvider imagePath]stringByAppendingPathComponent:#"default.png"];
NSURL *url = [[NSURL alloc]initWithString:defaultImagePath];
return #{#"body":#"", #"url":url};
}
#end