iOS 6 - UIActivityViewController项目

Question

希望大家都知道iOS 6包含ActionSheet (UIActivityViewController).的新样式UIActivityViewController可以使用像字符串，网址，图像等参数启动。下面是该代码片段（其中项目是一个数组与字符串和url参数）。

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

但是，当我们选择Mail，Facebook或Twitter等不同的共享选项时，我们可以分配不同的参数吗？

一种方法是我们可以实现UIActivityItemSource，我们需要实现的源方法

- (id)activityViewController:(UIActivityViewController *)activityViewController itemForActivityType:(NSString *)activityType 

它总是返回一个字符串值。但我需要传递一个数组，以便可以分配各种参数，如URL，图像和标题。

任何想法我们如何能够实现这一目标？

Answer 1

对于内置iOS UIActivityViewController项目（如Mail，Facebook和Twitter），您无法更改任何内容。为了实现UIActivityViewController中项目的自定义操作，您必须为每个需要的自定义活动创建UIActivity的自定义子类。这里有一个例子：

- (UIActivityViewController *)getActivityViewController { 
    MyFeedbackActivity *feedbackActivity = [[MyFeedbackActivity alloc] init]; 
    MyFacebookActivity *facebookActivity = [[MyFacebookActivity alloc] init]; 
    MyMailActivity *mailActivity = [[MyMailActivity alloc] init]; 

    NSArray *applicationActivities = @[feedbackActivity, facebookActivity, mailActivity]; 
    NSArray *activitiesItems = @[@"A string to be used for MyFeedbackActivity", @"A string to be used for MyFacebookActivity", @"A string to be used for MyMailActivity"]; 

    UIActivityViewController *activityVC = [[UIActivityViewController alloc] initWithActivityItems:activitiesItems applicationActivities:applicationActivities]; 

    // Removed un-needed activities 
    activityVC.excludedActivityTypes = [[NSArray alloc] initWithObjects: 
                UIActivityTypeCopyToPasteboard, 
                UIActivityTypePostToWeibo, 
                UIActivityTypePostToFacebook, 
                UIActivityTypeSaveToCameraRoll, 
                UIActivityTypeCopyToPasteboard, 
                UIActivityTypeMail, 
                UIActivityTypeMessage, 
                UIActivityTypeAssignToContact, 
                nil]; 

    return activityVC; 
} 

上，你会有兴趣覆盖到处理您的自定义数据/动作方法的文档子类化UIActivity非常有限的例子。

#import "MyFeedbackActivity.h" 

@implementation MyFeedbackActivity 

- (NSString *)activityType { 
    return @"MyFeedbackActivity"; 
} 

- (NSString *)activityTitle { 
    return @"Feedback"; 
} 

- (UIImage *)activityImage { 
    return [UIImage imageNamed:@"feedback"]; 
} 

- (BOOL)canPerformWithActivityItems:(NSArray *)activityItems { 
    return YES; 
} 

- (UIViewController *)activityViewController { 
    /** 
    * DESCRIPTION: 
    * Returns the view controller to present to the user. 
    * Subclasses that provide additional UI using a view controller can override this method to return that view controller. If this method returns a valid object, the system presents the returned view controller modally instead of calling the performActivity method. 
    * Your custom view controller should provide a view with your custom UI and should handle any user interactions inside those views. Upon completing the activity, do not dismiss the view controller yourself. Instead, call the activityDidFinish: method and let the system dismiss it for you. 
    */ 
} 

- (void)prepareWithActivityItems:(NSArray *)activityItems { 
    /** 
    * DESCRIPTION: 
    * Prepares your service to act on the specified data. 
    * The default implementation of this method does nothing. This method is called after the user has selected your service but before your service is asked to perform its action. Subclasses should override this method and use it to store a reference to the data items in the activityItems parameter. In addition, if the implementation of your service requires displaying additional UI to the user, you can use this method to prepare your view controller object and make it available from the activityViewController method. 
    */ 
} 

-(void)performActivity { 
    /** 
    * DESCRIPTION: 
    * Performs the service when no custom view controller is provided. 
    * The default implementation of this method does nothing. If your service does not provide any custom UI using the activityViewController method, override this method and use it to perform the activity. Your activity must operate on the data items received in the prepareWithActivityItems: method. 
    * This method is called on your app’s main thread. If your app can complete the activity quickly on the main thread, do so and call the activityDidFinish: method when it is done. If performing the activity might take some time, use this method to start the work in the background and then exit without calling activityDidFinish: from this method. Instead, call activityDidFinish: from your background thread after the actual work has been completed. 
    */ 
} 

@end