一、系统分享介绍

iOS系统自带的分享功能，可以让用户方便地将内容分享到社交媒体、邮件、信息等各种平台上，不用一一复制、粘贴或者进入其他app。iOS系统已经为开发者提供了强大的API，可以实现分享内容的自定义和更多的个性化设置。

二、分享内容类型

在iOS系统分享中，可以分享的内容类型主要包括文字、链接、图片、音频和视频等，下面分别介绍：

1. 文字分享

分享纯文本可以调用系统自带的分享面板，代码实现如下：

UIActivityViewController *activityVC = [[UIActivityViewController alloc]initWithActivityItems:@[@"分享的文本内容"] applicationActivities:nil];
[self presentViewController:activityVC animated:YES completion:nil];

2. 链接分享

分享链接同样也可以使用系统自带的分享面板，代码如下：

NSString *urlStr = @"http://www.example.com";
UIActivityViewController *activityVC = [[UIActivityViewController alloc]initWithActivityItems:@[[NSURL URLWithString:urlStr]] applicationActivities:nil];
[self presentViewController:activityVC animated:YES completion:nil];

3. 图片分享

图片分享可以使用系统提供的UIActivityViewController，并配合UIImagePickerViewController选择图片，代码实现如下：

UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
imagePicker.delegate = self;
imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
[self presentViewController:imagePicker animated:YES completion:nil];
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<UIImagePickerControllerInfoKey,id> *)info {
    UIImage* image = [info objectForKey:UIImagePickerControllerOriginalImage];
    NSArray *array = @[image];
    UIActivityViewController *activityVC = [[UIActivityViewController alloc]initWithActivityItems:array applicationActivities:nil];
    [picker dismissViewControllerAnimated:YES completion:nil];
    [self presentViewController:activityVC animated:YES completion:nil];
}

4. 音频分享

分享音频同样可以使用UIActivityViewController实现，具体代码如下：

NSArray *activityItems = @[[NSURL fileURLWithPath:self.audioPath]];
UIActivityViewController *activityController = [[UIActivityViewController alloc] initWithActivityItems:activityItems applicationActivities:nil];
[self presentViewController:activityController animated:YES completion:nil];

5. 视频分享

同样可以使用UIActivityViewController实现视频分享，代码如下：

NSArray *activityItems = @[[NSURL fileURLWithPath:self.videoPath]];
UIActivityViewController *activityController = [[UIActivityViewController alloc] initWithActivityItems:activityItems applicationActivities:nil];
[self presentViewController:activityController animated:YES completion:nil];

三、自定义分享

对于开发者来说，系统自带的分享功能无法满足需求时，可以自定义分享界面。下面介绍昵称、头像自定义分享：

1. 昵称自定义

首先创建分享的item，并通过UIActivityViewController分享，代码如下：

NSString *shareTitle = @"需要分享的标题";
UIImage *shareImage = [UIImage imageNamed:@"shareImage"];
NSURL *shareURL = [NSURL URLWithString:@"http://www.example.com"];
NSArray *activityItems = @[shareTitle, shareImage, shareURL];
WeChatSessionActivity *weChatSessionActivity = [[WeChatSessionActivity alloc]init];
WeChatTimeLineActivity *weChatTimelineActivity = [[WeChatTimeLineActivity alloc]init];
NSArray *activityArray = @[weChatSessionActivity,weChatTimelineActivity];
UIActivityViewController *activityController = [[UIActivityViewController alloc] initWithActivityItems:activityItems applicationActivities:activityArray];
activityController.excludedActivityTypes = @[UIActivityTypePostToWeibo, UIActivityTypeMessage, UIActivityTypePrint, UIActivityTypeCopyToPasteboard, UIActivityTypeAssignToContact, UIActivityTypeSaveToCameraRoll, UIActivityTypeAddToReadingList, UIActivityTypePostToFlickr, UIActivityTypePostToVimeo, UIActivityTypePostToTencentWeibo];
[self presentViewController:activityController animated:YES completion:^{
    NSLog(@"share action sheet shown");
}];

接着修改自定义的UIActivity实现，对于微信分享，可以修改WeChatSessionActivity和WeChatTimeLineActivity，在分享前弹框让用户输入昵称，代码如下（以WeChatSessionActivity为例）：

- (UIViewController *)activityViewController{
    return nil;
}
- (NSString *)activityType{
    return NSStringFromClass([self class]);
}
- (NSString *)activityTitle{
    return @"微信好友";
}
- (UIImage *)activityImage{
    return [UIImage imageNamed:@"ActivityIcon_WechatSession"];
}
- (BOOL)canPerformWithActivityItems:(NSArray *)activityItems{
    return YES;
}
- (void)prepareWithActivityItems:(NSArray *)activityItems{
    self.title = [activityItems objectAtIndex:0];
    self.image = [activityItems objectAtIndex:1];
    self.url = [activityItems objectAtIndex:2];
}
- (void)performActivity{
    UIAlertController *alertVC = [UIAlertController alertControllerWithTitle:@"请输入微信昵称" message:nil preferredStyle:UIAlertControllerStyleAlert];
    [alertVC addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField) {
        textField.placeholder = @"微信昵称";
    }];
    UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil];
    UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        WXMediaMessage *message = [WXMediaMessage message];
        message.title = self.title;
        message.description = @"";
        [message setThumbImage:self.image];
        WXWebpageObject *webpageObject = [WXWebpageObject object];
        webpageObject.webpageUrl = self.url.absoluteString;
        message.mediaObject = webpageObject;
        SendMessageToWXReq *req = [[SendMessageToWXReq alloc] init];
        req.bText = NO;
        req.message = message;
        req.scene = WXSceneSession;
        BOOL isSuccess = [WXApi sendReq:req];
        if (!isSuccess) {
            NSLog(@"微信分享失败");
        }
    }];
    [alertVC addAction:cancelAction];
    [alertVC addAction:okAction];
    UIViewController *currentVC = [UIApplication sharedApplication].keyWindow.rootViewController;
    [currentVC presentViewController:alertVC animated:YES completion:nil];
}

2. 头像自定义

同样保存昵称输入的内容，代码如下：

UIActivityViewController *activityController = [[UIActivityViewController alloc] initWithActivityItems:@[@{@"name":@"test", @"avatar":[UIImage imageNamed:@"avatar.jpg"]}] applicationActivities:nil];
[MomentsActivity registerAppSupport];
activityController.excludedActivityTypes = @[UIActivityTypePostToFacebook,
                                             UIActivityTypePostToTwitter,
                                             UIActivityTypePostToWeibo,
                                             UIActivityTypePostToVimeo,
                                             UIActivityTypePostToFlickr,
                                             UIActivityTypeMessage,
                                             UIActivityTypeMail,
                                             UIActivityTypePrint];
[self presentViewController:activityController animated:YES completion:nil];

微信朋友圈分享实现，代码如下：

- (void)performActivity{
    UIAlertController *alertVC = [UIAlertController alertControllerWithTitle:@"请输入微信昵称" message:nil preferredStyle:UIAlertControllerStyleAlert];
    [alertVC addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField) {
        textField.placeholder = @"微信昵称";
    }];
    UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil];
    UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        WXMediaMessage *message = [WXMediaMessage message];
        message.title = @"微信朋友圈";
        // 设置描述
        message.description = @"";
        UIImage *shareImage = [UIImage imageNamed:@"avatar.jpg"];
        [message setThumbImage:shareImage];
        WXImageObject *imageObject = [WXImageObject object];
        imageObject.imageData = UIImageJPEGRepresentation(shareImage, 0.5);
        message.mediaObject = imageObject;
        SendMessageToWXReq *req = [[SendMessageToWXReq alloc] init];
        req.bText = NO;
        req.message = message;
        req.scene = WXSceneTimeline;
        [WXApi sendReq:req];
    }];
    [alertVC addAction:cancelAction];
    [alertVC addAction:okAction];
    UIViewController *currentVC = [UIApplication sharedApplication].keyWindow.rootViewController;
    [currentVC presentViewController:alertVC animated:YES completion:nil];
}

四、总结

iOS系统分享功能能够方便地将内容分享到多个社交媒体、邮件、信息等平台上。系统自带的UIActivityViewController提供了功能齐全的默认分享面板，而自定义分享方式可以大大提高用户体验。开发者可以根据需求选择对应的分享方式来满足分享需求。

iOS系统分享详解