在一个新的视图控制器UIImageView中显示图像

Question

我先把我的代码贴出来，然后再解释问题

RootViewController.h它叫做SpViewController.h

#import <UIKit/UIKit.h>
#import <MobileCoreServices/MobileCoreServices.h>
#import "secondViewController.h"
@interface spViewController : UIViewController

<UIImagePickerControllerDelegate,
UINavigationControllerDelegate>
@property BOOL newMedia;

@property (strong, nonatomic) IBOutlet UIImageView *imageView;
@property (strong, nonatomic) spViewController *secondViewController;
@property (strong, nonatomic) UIImageView *image;
@property (strong, nonatomic) UIImage *myImage;
- (IBAction)useCamera:(id)sender;

- (IBAction)useCameraRoll:(id)sender;

@end

spViewController.m

   #import "spViewController.h"
#import "secondViewController.h"
@interface spViewController ()
@end
@implementation spViewController
- (IBAction)backtohome:(UIStoryboardSegue *)unwindSegue
{
}
- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}
- (void) viewDidAppear:(BOOL)animated{
    [super viewDidAppear:animated];
}
- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
- (IBAction)useCamera:(id)sender {
        if ([UIImagePickerController isSourceTypeAvailable:
             UIImagePickerControllerSourceTypeCamera])
        {
            UIImagePickerController *imagePicker =
            [[UIImagePickerController alloc] init];
            imagePicker.delegate = self;
            imagePicker.sourceType =
            UIImagePickerControllerSourceTypeCamera;
            imagePicker.mediaTypes = @[(NSString *) kUTTypeImage];
            imagePicker.allowsEditing = NO;
            [self presentViewController:imagePicker
                               animated:YES completion:nil];
            _newMedia = YES;
        }
    }
- (IBAction)useCameraRoll:(id)sender {
    if ([UIImagePickerController isSourceTypeAvailable:
         UIImagePickerControllerSourceTypeSavedPhotosAlbum])
    {
        UIImagePickerController *imagePicker =
        [[UIImagePickerController alloc] init];
        imagePicker.delegate = self;
        imagePicker.sourceType =
        UIImagePickerControllerSourceTypePhotoLibrary;
        imagePicker.mediaTypes = @[(NSString *) kUTTypeImage];
        imagePicker.allowsEditing = NO;
        [self presentViewController:imagePicker
                           animated:YES completion:nil];
        _newMedia = NO;
    }
}

//image picker delegate
-(void)imagePickerController:(UIImagePickerController *)picker
didFinishPickingMediaWithInfo:(NSDictionary *)info
{
UIImage *chosenImage = info[UIImagePickerControllerEditedImage]; self.myImage =  chosenImage;
    NSString *mediaType = info[UIImagePickerControllerMediaType];
    [self performSelector:@selector(myMethod:) withObject:info afterDelay:0.1];
    if ([mediaType isEqualToString:(NSString *)kUTTypeImage]) {
        UIImage *image = info[UIImagePickerControllerOriginalImage];
        _imageView.image = image;
        if (_newMedia)
            UIImageWriteToSavedPhotosAlbum(image,
                                           self,
                                           @selector(image:finishedSavingWithError:contextInfo:),
                                           nil);
    }
    else if ([mediaType isEqualToString:(NSString *)kUTTypeMovie])
    {
    }
}
-(void)myMethod:(NSDictionary *)info {
    [self dismissViewControllerAnimated:YES completion:^{
        NSLog(@"Perform segue");
        [self performSegueWithIdentifier:@"Picture Unwind Segue" sender:self];
    }];
}

-(void)image:(UIImage *)image
finishedSavingWithError:(NSError *)error
 contextInfo:(void *)contextInfo
{
    if (error) {
        UIAlertView *alert = [[UIAlertView alloc]
                              initWithTitle: @"Save failed"
                              message: @"Failed to save image"
                              delegate: nil
                              cancelButtonTitle:@"OK"
                              otherButtonTitles:nil];
        [alert show];
    }
}
//cancel delegate
-(void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
    [self dismissViewControllerAnimated:YES completion:nil];
}

 -(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    if ([[segue identifier]isEqualToString:@"Picture Unwind Segue"]) {
        secondViewController *destinationViewController = [segue destinationViewController];
        destinationViewController.imageView.image = self.myImage;
    }
}
@end

secondViewController.h

#import <UIKit/UIKit.h>
#import <MobileCoreServices/MobileCoreServices.h>
#import "spViewController.h"
@interface secondViewController : UIViewController
<UIImagePickerControllerDelegate,
UINavigationControllerDelegate>
@property (strong, nonatomic) IBOutlet UIImageView *imageView;
@property (strong, nonatomic) UIImage *myImage;
@property (strong, nonatomic) UIImageView *image;
@end

secondViewController.m

#import "secondViewController.h"
#import "spViewController.h"
@interface secondViewController ()
@end
@implementation secondViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

 - (void)viewDidLoad
{
    self.imageView.image = self.myImage;
    [super viewDidLoad];
         }
- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
/*
#pragma mark - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/
@end

所以我遇到的问题是，我无法获得刚刚在UIImagePickerController中选择的图像显示在UIImageView中，我的ImagePickerController是由我以前的视图控制器"spViewController"(rootViewController)中的按钮启动的，我正在使用故事板，我想如果我放入UIImageView然后使用出口引用连接它它会显示在那里，但情况似乎并非如此。如果我把UIImageView放到第一个视图控制器中并做同样的事情它会显示图像，但这不是我想要的。

感谢您的帮助

Answer 1

为了解决我的问题，我决定保存图像并稍后调用它，这里是我放入我的secondViewController.m的代码

{NSString *docsPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    NSString *filepathJPG = [docsPath stringByAppendingPathComponent:@"imagefile.jpg"];
    UIImage *img = [UIImage imageWithContentsOfFile: filepathJPG];
    if (img != nil) {
        // assign the image to the imageview,
        _imageView.image = img;
        // Optionally adjust the size
        BOOL adjustToSmallSize = YES;
        CGRect smallSize = (CGRect){0,0,100,100};
        if (adjustToSmallSize) {
            _imageView.bounds = smallSize;
        }
    }

我希望这能帮助到其他有同样问题的人。

Answer 2

所以根据你的代码，你正在设置myImage的属性，这是一个来自RootViewController的UIImage实例。

所以你只是传递图像的数据，但你没有将imageView.image属性设置为传递的图像值。

所以一个可能的解决方案是设置imageView.image = myImage in viewDidLoad

或

你可以直接从RootViewController中的perform prepare for segue方法访问imageView属性，并设置它的image属性。

我希望这对你有帮助。欢呼声

Answer 3

你可以在AppDelegate类中声明一个属性，并使用AppDelegate共享实例跨所有控制器访问它