IOS相册或者照相机图片的选择

#import "ViewController.h"

@interface ViewController ()<UIImagePickerControllerDelegate, UINavigationControllerDelegate>
@property (weak, nonatomic) IBOutlet UIImageView *imageView;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}
- (IBAction)chooseImage:(id)sender {
    UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];
    imagePickerController.delegate = self;
    imagePickerController.allowsEditing = YES;
    
    UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"选取图片" message:nil preferredStyle:UIAlertControllerStyleActionSheet];
    
    UIAlertAction *cameraAction = [UIAlertAction actionWithTitle:@"拍照" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        imagePickerController.sourceType = UIImagePickerControllerSourceTypeCamera;
        imagePickerController.cameraDevice = UIImagePickerControllerCameraDeviceFront;
        [self presentViewController:imagePickerController animated:YES completion:^{}];
    }];
    
    UIAlertAction *photosAction = [UIAlertAction actionWithTitle:@"从相册选择" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        imagePickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
        [self presentViewController:imagePickerController animated:YES completion:^{}];
    }];
    
    UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
    }];
    
    if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
    {
        [alert addAction:cameraAction];
    }
    
    [alert addAction:photosAction];
    [alert addAction:cancelAction];
    
    [self presentViewController:alert animated:YES completion:nil];
}

#pragma mark - UIImagePickerControllerDelegate
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
    
    [picker dismissViewControllerAnimated:YES completion:nil];
    UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];
    self.imageView.image = image;
    SEL selectorToCall = @selector(image:didFinishSavingWithError:contextInfo:);

    UIImageWriteToSavedPhotosAlbum(image, self, selectorToCall, NULL);
}

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

- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo {
    if (error == nil){
        NSLog(@"Image was saved successfully.");
    } else {
        NSLog(@"An error happened while saving the image.");
        NSLog(@"Error = %@", error);
    }
}

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

@end