核心数据和 UIActivityViewController

Question

我的应用程序正在使用核心数据来持久化数据。我的主 VC 上有一个 UIActivityViewController 设置。一切都按我的预期工作。

我的问题是，当您从核心数据模型中获取项目时，您如何让它返回模型中的每个项目？

我应该使用谓词对项目进行排序吗？

编辑

这是我的 UIActivityViewController 设置。我知道一些 UIActivityViewController 动作没有出现在 sim 中，这很好。我正在使用确实出现的电子邮件操作。我看到我的 NSString 和 NSURL 显示没有问题，但我的 itemnames NSArray 没有显示。它应该出现在 sim 卡中吗？

- (IBAction)ShareItem:(id)sender {

NSString *textToShare = @"This is just some random text I put here";
NSURL *myWebsite = [NSURL URLWithString:@"http://www.martylavender.com/"];

NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:@"Item"];
fetchRequest.resultType = NSDictionaryResultType;

NSError *error      = nil;
NSArray *results    = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];

NSMutableArray *itemNames = [results valueForKey:@"itemname"];

NSArray *objectsToShare = @[textToShare, myWebsite, itemNames];

UIActivityViewController *activityVC = [[UIActivityViewController alloc] initWithActivityItems:objectsToShare applicationActivities:nil];

NSArray *excludeActivities = @[UIActivityTypeAirDrop,
                               UIActivityTypePrint,
                               UIActivityTypePostToTwitter,
                               UIActivityTypeAssignToContact,
                               UIActivityTypeSaveToCameraRoll,
                               UIActivityTypeAddToReadingList,
                               UIActivityTypePostToFlickr,
                               UIActivityTypePostToVimeo];

activityVC.excludedActivityTypes = excludeActivities;

[self presentViewController:activityVC animated:YES completion:nil];
NSLog(@"%@", itemNames); 
}

我确实看到我的项目在控制台中打印出来了。也许他们只是不会显示在 sim 中？

编辑

我想我可能知道它为什么不显示。 UIActivityTypeMail 说它支持：字符串、属性字符串和 url。不支持数据、图像、资产。

编辑

好的，想通了。我需要把我的 NSMutableArray 转换成一个 NSString。 NSString 有一个方法可以将你的数组放入字符串中。它也有逆向，它将把你的字符串粘到一个数组中。话虽如此。

这是更新的代码。我只需要弄清楚将文本放入电子邮件后如何格式化它，这将是金色的。

- (IBAction)ShareItem:(id)sender {

NSString *textToShare = @"This is just some random text I put here";
NSURL *myWebsite = [NSURL URLWithString:@"http://www.martylavender.com/"];

NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:@"Item"];
fetchRequest.resultType = NSDictionaryResultType;

NSError *error      = nil;
NSArray *results    = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];
NSMutableArray *itemNames = [results valueForKey:@"itemname"];
NSString *names = [itemNames componentsJoinedByString:@""];
NSLog(@"%@",names);



NSArray *objectsToShare = @[textToShare, myWebsite, names];

UIActivityViewController *activityVC = [[UIActivityViewController alloc] initWithActivityItems:objectsToShare applicationActivities:nil];

NSArray *excludeActivities = @[UIActivityTypeAirDrop,
                               UIActivityTypePrint,
                               UIActivityTypePostToTwitter,
                               UIActivityTypeAssignToContact,
                               UIActivityTypeSaveToCameraRoll,
                               UIActivityTypeAddToReadingList,
                               UIActivityTypePostToFlickr,
                               UIActivityTypePostToVimeo];

activityVC.excludedActivityTypes = excludeActivities;

[self presentViewController:activityVC animated:YES completion:nil];
}

编辑

我完全把事情复杂化了。我只是在这里删除了\n：NSString *names = [itemNames componentsJoinedByString:@""];，这让它们在每个项目之后都下降到新的一行。

Answer 1

- (IBAction)ShareItem:(id)sender {

NSString *textToShare = @"This is just some random text I put here";
NSURL *myWebsite = [NSURL URLWithString:@"http://www.martylavender.com/"];

NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:@"Item"];
fetchRequest.resultType = NSDictionaryResultType;

NSError *error      = nil;
NSArray *results    = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];
NSMutableArray *itemNames = [results valueForKey:@"itemname"];
NSString *names = [itemNames componentsJoinedByString:@" \n"];
NSLog(@"%@",names);



NSArray *objectsToShare = @[textToShare, myWebsite, names];

UIActivityViewController *activityVC = [[UIActivityViewController alloc] initWithActivityItems:objectsToShare applicationActivities:nil];

NSArray *excludeActivities = @[UIActivityTypeAirDrop,
                               UIActivityTypePrint,
                               UIActivityTypePostToTwitter,
                               UIActivityTypeAssignToContact,
                               UIActivityTypeSaveToCameraRoll,
                               UIActivityTypeAddToReadingList,
                               UIActivityTypePostToFlickr,
                               UIActivityTypePostToVimeo];

activityVC.excludedActivityTypes = excludeActivities;

[self presentViewController:activityVC animated:YES completion:nil];
}

编辑

我完全把事情复杂化了。我只是在这里删除了一个\n：NSString *names = [itemNames componentsJoinedByString:@""];，这让它们在每个项目之后都下降到一个新行。