关于如何使用代码触发 UIButton的Unwind Segue

- (IBAction)DonePhotoButton:(UIButton *)sender {
}//按键事件 

#pragma mark - prepareForSegue
//prepare
-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
    if ([segue.identifier isEqualToString:kUNWIND_ID]) {
        NSManagedObjectContext * context = self.photographyerTakingPhoto.managedObjectContext;
        if (context) {
            Photo * photo = [NSEntityDescription insertNewObjectForEntityForName:@"Photo" inManagedObjectContext:context];
            photo.title     = self.TextFieldTitle.text;
            photo.subtitle  = self.TextFieldSubTitle.text;
            photo.whoTook   = self.photographyerTakingPhoto;
            photo.latitude  = [NSNumber numberWithDouble:self.location.coordinate.latitude];
            photo.longitude = [NSNumber numberWithDouble:self.location.coordinate.longitude];
            photo.imageURL  = [self.imageURL absoluteString];
            photo.thumbnailURL = [self.thumnailURL absoluteString];
            self.photo = photo;
        }
    }
}
//判断identifer 决定是否执行prepareForSegue 同时给出警告
-(BOOL) shouldPerformSegueWithIdentifier:(NSString *)identifier sender:(id)sender{
    if ([identifier isEqualToString:kUNWIND_ID]) {
        if (!self.image) {
            [self alert:@"No Photo taken!"];
            return NO;
        }else if(![self.TextFieldTitle.text length] || ![self.TextFieldSubTitle.text length]){
            [self.TextFieldTitle.text length]       ? [self alert:@"SubTitle required!"]       :
            [self.TextFieldSubTitle.text length]    ?  [self alert:@"Title required!"]   : [self alert:@"Title and SubTitle required"] ;
            return NO;
        }else{
            return YES;
        }
    }else{
        return [super shouldPerformSegueWithIdentifier:identifier sender:sender];
    }
}

//----------------------------------------------------------------//
//点击键盘的return取消键盘
-(BOOL)textFieldShouldReturn:(UITextField *)textField{
    [textField resignFirstResponder];
    BOOL CanSegue = [self shouldPerform:kUNWIND_ID];
    if (CanSegue)
        [self performSegueWithIdentifier:kUNWIND_ID sender:nil];
    
    return YES;
}

-(BOOL) shouldPerform:(NSString *)identifier  {
    if ([identifier isEqualToString:kUNWIND_ID]) {
        if (!self.image) {
            [self alert:@"No Photo taken!"];
            return NO;
        }else if(![self.TextFieldTitle.text length] || ![self.TextFieldSubTitle.text length]){
            [self.TextFieldTitle.text length]       ? [self alert:@"SubTitle required!"]       :
            [self.TextFieldSubTitle.text length]    ?  [self alert:@"Title required!"]   : [self alert:@"Title and SubTitle required"] ;
            return NO;
        }else{
            return YES;
        }
    }else{
        return NO;
    }

}