如何通过UIActivityViewController使用UIActivityItemProvider发送带有附件的电子邮件？

Question

我正在尝试使用UIActivityItemProvider通过电子邮件附件从我的应用程序中共享文件。我还需要填充电子邮件的主题行，并指定附件的名称不同于存储在设备上的文件的名称。

这是我正在使用的代码。问题是电子邮件中缺少附件。

@interface ItemProvider:UIActivityItemProvider
@property (nonatomic, strong) NSURL *filepath;
@property (nonatomic, strong) NSString *emailBody;
@property (nonatomic, strong) NSString *emailSubject;
@end

@implementation ItemProvider

- (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
    return [NSDictionary dictionary];
}

// The following are two methods in the UIActivityItemSource Protocol
// (UIActivityItemProvider conforms to this protocol) - both methods required
#pragma mark UIActivityItemSource

//- Returns the data object to be acted upon. (required)
- (id)activityViewController:(UIActivityViewController *)activityViewController itemForActivityType:(NSString *)activityType
{


    if ([activityType isEqualToString:UIActivityTypeMail]) {
        return @{@"body":self.emailBody, @"url":self.filepath};
    }


    return @{@"body":self.emailBody, @"url":self.filepath};
}

//- Returns the placeholder object for the data. (required)
//- The class of this object must match the class of the object you return from the above method
- (id)activityViewControllerPlaceholderItem:(UIActivityViewController *)activityViewController
{
    return @{@"body":self.emailBody, @"url":self.filepath};
}

-(NSString *) activityViewController:(UIActivityViewController *)activityViewController subjectForActivityType:(NSString *)activityType {
    return self.emailSubject;
}

@end

然后在我的viewController中，我这样做：

      ItemProvider *provider = [[ItemProvider alloc] initWithPlaceholderItem:@{@"body":emailBody, @"url":filePath}];
    provider.emailBody = emailBody;
    provider.emailSubject = info.title;
    provider.filepath = filePath;
    NSArray *activityItems = @[provider];

    // Build a collection of custom activities (if you have any)
//    NSMutableArray *customActivities = [[NSMutableArray alloc] init];


    UIActivityViewController *activityController = [[UIActivityViewController alloc] initWithActivityItems:activityItems applicationActivities:nil];

    [self presentViewController:activityController animated:YES completion:nil];

Answer 1

我正在发送带有附件的电子邮件，但没有使用ItemProvider。它工作正常:-)

NSMutableArray *selDocs = [[NSMutableArray alloc] init];
for (Document *theDoc in self.selectedDocs) {
     NSURL *fileUrl = [NSURL fileURLWithPath:theDoc.filePath];       
    [selDocs addObject:fileUrl];
}
NSArray *postItems = [NSArray arrayWithArray:selDocs];

UIActivityViewController *avc = [[UIActivityViewController alloc] initWithActivityItems:postItems applicationActivities:nil];
[avc setValue:@"Your email Subject" forKey:@"subject"];

avc.completionHandler = ^(NSString *activityType, BOOL completed){
    NSLog(@"Activity Type selected: %@", activityType);
    if (completed) {
        NSLog(@"Selected activity was performed.");
    } else {
        if (activityType == NULL) {
            NSLog(@"User dismissed the view controller without making a selection.");
        } else {
            NSLog(@"Activity was not performed.");
        }
    }
};

[self presentViewController:avc animated:YES completion:nil];

Answer 2

对于那些仍在寻找解决方案的人来说，有一个更优雅的定制UIActivityViewController的解决方案。为了解决最初的问题，附件没有出现的原因是因为它应该是一个单独的UIActivityItemProvider对象。

因此，解决方案是创建两个UIActivityItemProvider子类，一个用于包装“emailBody”和“emailSubject”，另一个用于包装附件。对附件使用UIActivityItemProvider的好处是，您可以将处理附件的时间推迟到需要时，而不是在提交UIActivityViewController之前进行。

实现AttachmentProvider类，如下所示提供附件：

@implementation AttachmentProvider : UIActivityItemProvider

- (id)item {
    if ([self.activityType isEqualToString:UIActivityTypeMail]) {

        /* Replace with actual URL to a file. Alternatively
         * you can also return a UIImage.
         */

        return [NSData dataWithContentsOfURL:dataURL];
    }
    return nil;
}

@end

实现EmailInfoProvider类来提供电子邮件正文和subject类，如下所示：

@implementation EmailInfoProvider : UIActivityItemProvider

- (id)item {
    return @"Your email body goes here";
}

- (NSString *)activityViewController:(UIActivityViewController *)activityViewController subjectForActivityType:(NSString *)activityType {
    if ([activityType isEqualToString:UIActivityTypeMail]) {
        return @"Your subject goes here";
    }
    return nil;
}

@end

然后，您可以在viewController中使用这两个项创建一个UIActivityViewController，如下所示：

- (void)shareAction {

    AttachmentProvider *attachment  = [[AttachmentProvider alloc] init];
    EmailInfoProvider *emailContent = [[EmailInfoProvider alloc] init];

    // You can provider custom -(id)init methods to populate EmailInfoProvider

    UIActivityViewController *activityController = [[UIActivityViewController alloc] initWithActivityItems:@[attachment, emailContent] applicationActivities:nil];
    [self presentViewController:activityController animated:YES completion:nil];
}