iOS AlertView - 它可以是原子的，以便后台进程必须等待吗？

Question

在使用我的应用程序中加载的相机拍照时，我一直在尝试为照片添加标题。它正在做的是它拍摄照片然后一旦我点击＆＃34;使用照片＆＃34;为了保存它，它将在用户保存他们想要的标题之前保存它。它实际上会将该标题添加到您拍摄的下一张照片中。我也可以设置它，以便在拍照之前要求输入标题，但这很尴尬。

如果我可以向相机添加另一个动作按钮会有所帮助，但我不知道我会怎么做。

这是我到目前为止所做的：

- (void) imagePickerController: (UIImagePickerController*) picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

[self getUserCaption];//calls alertview to get caption from user

// Declare Variables
NSString *mediaType = [info objectForKey: UIImagePickerControllerMediaType];
UIImage *originalImage, *editedImage, *imageToSave;

// Process for saving an image
if (CFStringCompare ((CFStringRef) mediaType, kUTTypeImage, 0)== kCFCompareEqualTo) { //if it's an image

    editedImage = (UIImage *) [info objectForKey:
                               UIImagePickerControllerEditedImage]; //Assign the edited image to editedImage
    originalImage = (UIImage *) [info objectForKey:
                                 UIImagePickerControllerOriginalImage]; //Assign the original image to originalImage

    //Check to see if there was indeed an edited image, if so use that, otherwise use the original
    if (editedImage) {
        //imageToSave = editedImage;
        imageToSave = [self addCaption:editedImage];
    } else {
        //imageToSave = originalImage;
        imageToSave = [self addCaption:originalImage];
    }

    // Saves the image into the documents folder
    NSArray *paths = NSSearchPathForDirectoriesInDomains
    (NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];

    NSDate *today = [NSDate date];
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"yyyy-MM-dd"];

    NSString *todayDate = [dateFormatter stringFromDate:today];
    NSString *fileName = [NSString stringWithFormat:@"%@/%@_%@_%@.jpg",documentsDirectory,
                          todayDate,self.passedProjectName,self.passedYourName];
    NSString *fileCheck = [NSString stringWithFormat:@"%@_%@_%@.jpg",todayDate,
                           self.passedProjectName,self.passedYourName];

    saveNumber = 0;
    while ([self checkImageFileName:fileCheck]) {
        saveNumber++;
        fileName = [NSString stringWithFormat:@"%@/%@_%@_%@_%i.jpg",documentsDirectory,
                              todayDate,self.passedProjectName,self.passedYourName,saveNumber];
        fileCheck = [NSString stringWithFormat:@"%@_%@_%@_%i.jpg",todayDate,
                     self.passedProjectName,self.passedYourName,saveNumber];
        //NSLog(@"File name was the same");
    }

    NSData *imageData = [NSData dataWithData:UIImageJPEGRepresentation(imageToSave, 1)];
    [imageData writeToFile:fileName atomically:YES];
    // Save the image to the Camera Roll
    //UIImageWriteToSavedPhotosAlbum (imageToSave, nil, nil , nil);
}
// Process for saving a video
if (CFStringCompare ((CFStringRef) mediaType, kUTTypeMovie, 0)
    == kCFCompareEqualTo) {//if it's a video
    //define the movie
    NSString *moviePath = [[info objectForKey:
                            UIImagePickerControllerMediaURL] path];
    //if possible, save in the camera roll
    if (UIVideoAtPathIsCompatibleWithSavedPhotosAlbum (moviePath)) {
        UISaveVideoAtPathToSavedPhotosAlbum (
                                             moviePath, nil, nil, nil);
    }
}
[picker dismissModalViewControllerAnimated: YES]; //Dismiss the controller
[self.viewPhoto setImage:imageToSave]; //Assign the picture to the image view

} //结束imagePickerController

- (BOOL)getUserCaption{

UIAlertView * alert = [[UIAlertView alloc] initWithTitle:@"Great shot!" message:@"Please enter a caption for this photo" delegate:self cancelButtonTitle:@"Save" otherButtonTitles:nil];
alert.alertViewStyle = UIAlertViewStylePlainTextInput;

UITextField * alertTextField = [alert textFieldAtIndex:0];
alertTextField.keyboardType = UIKeyboardTypeDefault;
alertTextField.placeholder = @"Enter caption";
//[alert show];
[alert performSelectorOnMainThread:@selector(show) withObject:nil waitUntilDone:TRUE];

return true;

}

- (void)alertView:(UIAlertView *)alert clickedButtonAtIndex:(NSInteger)buttonIndex {
NSLog(@"entered alertCAption");
if (buttonIndex == 0) {
    NSLog(@"buttonIndex was 0");
    caption = [alert textFieldAtIndex:0].text;
    gotCaption = true;
    NSLog(@"%@",caption);
}

}

- (UIImage*)addCaption:(UIImage*)imageToSave

{

UIColor *textColor = [UIColor colorWithWhite:1.0 alpha:1.0];
UIFont *font = [UIFont systemFontOfSize:50];
CGFloat paddingX = 20.f;
CGFloat paddingY = 20.f;

// Compute rect to draw the text inside
CGSize imageSize = imageToSave.size;

NSDictionary *attr = @{NSForegroundColorAttributeName: textColor, NSFontAttributeName: font};
CGSize textSize = [caption sizeWithAttributes:attr];
CGRect textRect = CGRectMake(imageSize.width - textSize.width - paddingX, imageSize.height - textSize.height - paddingY, textSize.width, textSize.height);

// Create the image
UIGraphicsBeginImageContext(imageSize);
[imageToSave drawInRect:CGRectMake(0, 0, imageSize.width, imageSize.height)];

// Create the background for caption
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetRGBFillColor(context, 0.0, 0.0, 0.0, 0.6);
// Add Filled Rectangle,
CGContextFillRect(context, CGRectMake(imageSize.width - textSize.width - paddingX-10, imageSize.height - textSize.height - paddingY-10, (textSize.width+20), (textSize.height+20)));

[caption drawInRect:CGRectIntegral(textRect) withAttributes:attr];

UIImage *resultImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

return resultImage;

}