ios - UIImagePickerController 相机空白快照图像

Question

我正在尝试使用 UIImagePickerControllerSourceTypeCamera 拍照。当我在快照中拍摄照片时，我得到一张空白照片，但如果我选择使用照片我可以看到它我是我的 UIImage:

我也在控制台中收到这些错误:

: CGAffineTransformInvert: singular matrix.

和

Snapshotting a view that has not been rendered results in an empty snapshot. Ensure your view has been rendered at least once before snapshotting or snapshot after screen updates.

这是我的代码:

- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
 }

- (void)viewDidAppear:(BOOL)animated {

  [super viewDidAppear:animated];

}

- (void)didReceiveMemoryWarning
{
  [super didReceiveMemoryWarning];
  // Dispose of any resources that can be recreated.
}

- (IBAction)takePhoto:(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)selectPhoto:(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;
}

}

#pragma mark UIImagePickerControllerDelegate

-(void)imagePickerController:(UIImagePickerController *)picker
 didFinishPickingMediaWithInfo:(NSDictionary *)info
{
NSString *mediaType = info[UIImagePickerControllerMediaType];

[self dismissViewControllerAnimated:YES completion:nil];

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])
{
    // Code here to support video if enabled
}
}

-(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];
}
}

-(void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
 [self dismissViewControllerAnimated:YES completion:nil];
}

Answer 1

我已经测试了你的代码，它工作正常。我认为您面临的问题与此问题有关...

Snapshotting a view that has not been rendered results in an empty snapshot. Ensure your view has been rendered at least once before snapshotting or snapshot after screen updates.

查看这篇文章；这可能会帮助你... UIImagePickerController error: Snapshotting a view that has not been rendered results in an empty snapshot in iOS 7

这是完整的代码，以防万一您遗漏了什么...
ViewController.h

#import <UIKit/UIKit.h>
@interface ViewController : UIViewController <UIImagePickerControllerDelegate, UINavigationControllerDelegate>
@property (nonatomic, weak) IBOutlet UIImageView *imageView;
- (IBAction)takePhoto:(id)sender;
- (IBAction)selectPhoto:(id)sender;
@end

ViewController.m

#import "ViewController.h"
@import MobileCoreServices;

@interface ViewController ()
@property (nonatomic, readwrite) BOOL newMedia;
@end

@implementation ViewController
- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
}

- (void)viewDidAppear:(BOOL)animated {

    [super viewDidAppear:animated];

}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (IBAction)takePhoto:(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)selectPhoto:(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;
    }

}

//- (IBAction)takePhoto_

#pragma mark UIImagePickerControllerDelegate

-(void)imagePickerController:(UIImagePickerController *)picker
didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    NSString *mediaType = info[UIImagePickerControllerMediaType];

    [self dismissViewControllerAnimated:YES completion:nil];

    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])
    {
        // Code here to support video if enabled
    }
}

-(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];
    }
}

-(void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
    [self dismissViewControllerAnimated:YES completion:nil];
}

@end