当我点击图像中的完成按钮时，会在之前的UIviewController中进行更改吗？

Question

当我点击图片时，我会更改个人资料图片第一个屏幕，它将进入下一个屏幕，并在此请求从图库中选择或拍照。假设我从图库中选择，它进入第二个屏幕并且图像出现。我的问题是，当我在第二个屏幕上点击完成按钮时，图像将在第一个屏幕中更改，即个人资料图片。如何在第一个屏幕中更改，请回复我。

Answer 1

在SecondViewController课程中创建委托。在FirstViewController类中分配并实现此委托。

当用户从图库中选择图片或点击照片时，请调用委托方法将所选图片传递给FirstViewController课程。

实现此目的的示例代码如下

SecondViewController.h

// Declare delegate
@protocol ImageSelectionDelegate <NSObject>
- (void) imageSelected:(UIImage*)image;
@end

@interface SecondViewController : UIViewController
// Delegate property
@property (nonatomic,assign) id<ImageSelectionDelegate> delegate;
@end

SecondViewController.m

@implementation SecondViewController

// In case you are using image picker, this delegate is called once image selection is complete.
- (void)imagePickerController:(UIImagePickerController *)picker
                        didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    //Use either according to your setting, whether you allow image editing or not.
    UIImage *myImage = [info objectForKey:UIImagePickerControllerEditedImage];
    //For edited image
    //UIImage *myImage = [info objectForKey:UIImagePickerControllerOriginalImage];
    if([_delegate respondsToSelector:@selector(imageSelected:)]) {
        [self.delegate imageSelected:myImage];
    }
}

//OR

// Done button click
- (IBAction)doneButtonClick:(id)sender
{
    // You can store the image selected by user in a UIImage pointer.
    // Here I have UIImage *selectedImage as an ivar.

    // Call the delegate and pass the selected image.
    if([_delegate respondsToSelector:@selector(imageSelected:)]) {
        [self.delegate imageSelected:selectedImage];
    }

    // Pop the view controller here
}

@end

FirstViewController.h

#import "SecondViewController.h"

@interface FirstViewController : UIViewController <ImageSelectionDelegate>

@end

FirstViewController.m

@implementation FirstViewController
- (void) onImageClick {
    SecondViewController *controller = [[SecondViewController alloc] initWithNibName:@"SecondViewController" bundle:nil];
    // Assign delegate
    controller.delegate = self;
    [self.navigationController pushViewController:controller animated:YES];
}

// Implement delegate method
- (void) imageSelected:(UIImage *)image {
    // Use image
}
@end