objective-c : using UIImagePickerController

snippet.m

//using UIImagePickerController

//TWPhotosCollectionViewController.h

@interface TWPhotosCollectionViewController : UICollectionViewController

- (IBAction)cameraBarButtonItemPressed:(UIBarButtonItem *)sender;

@end


//TWPhotosCollectionViewController.m

#import "TWPhotosCollectionViewController.h"
#import "TWPhotoCollectionViewCell.h" //커스텀 컬렉션 뷰 셀

//UIImagePickerController는 UIImagePickerControllerDelegate, UINavigationControllerDelegate 두 델리게이션 모두 필요함
@interface TWPhotosCollectionViewController () <UIImagePickerControllerDelegate, UINavigationControllerDelegate>

@property (strong, nonatomic) NSMutableArray *photos; //Of UIImaqges

@end

@implementation TWPhotosCollectionViewController

- (NSMutableArray *)photos
{
    if (debug==1) {NSLog(@"Running %@ '%@'", self.class, NSStringFromSelector(_cmd));}
    
    if (!_photos) {
        _photos = [[NSMutableArray alloc] init];
    }
    
    return _photos;
}


#pragma mark - IBAction

- (IBAction)cameraBarButtonItemPressed:(UIBarButtonItem *)sender
{
    if (debug==1) {NSLog(@"Running %@ '%@'", self.class, NSStringFromSelector(_cmd));}
    
    //UIImagePickerController 오브젝트
    UIImagePickerController *picker = [[UIImagePickerController alloc] init];
    picker.delegate = self; //델리게이트
    
    //카메라 또는 포토앨범 선택
    if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
        picker.sourceType = UIImagePickerControllerSourceTypeCamera;
        
    } else if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeSavedPhotosAlbum]) {
        picker.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
    }
    
    //present 뷰컨트롤러
    [self presentViewController:picker animated:YES completion:^{
        NSLog(@"Picker View done presenting");
    }];
    
}


#pragma mark - UICollectionView 데이터 소스

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    if (debug==1) {NSLog(@"Running %@ '%@'", self.class, NSStringFromSelector(_cmd));}
    
    static NSString *CellIdentifier = @"Photo Cell";
    
    //커스텀 컬렉션 뷰 셀 사용
    TWPhotoCollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:CellIdentifier
                                                                           forIndexPath:indexPath];
    cell.backgroundColor = [UIColor whiteColor];
    cell.imageView.image = self.photos[indexPath.row];
    
    return cell;
}


- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    if (debug==1) {NSLog(@"Running %@ '%@'", self.class, NSStringFromSelector(_cmd));}
    
    return [self.photos count];
}



#pragma mark - UIImagePickerController 델리게이트

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    if (debug==1) {NSLog(@"Running %@ '%@'", self.class, NSStringFromSelector(_cmd));}
    
    NSLog (@"Finish image picking");
    
    UIImage *image= info[UIImagePickerControllerEditedImage];
    if (!image) image = info[UIImagePickerControllerOriginalImage];
        
        [self.photos addObject:image];
        
        [self.collectionView reloadData];

    //이미지 피커 뷰 해제
    [self dismissViewControllerAnimated:YES completion:^{
        NSLog(@"Finished image picking");
    }];

}


- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
    if (debug==1) {NSLog(@"Running %@ '%@'", self.class, NSStringFromSelector(_cmd));}
    
    NSLog (@"Image picker cancelled");
    
    //이미지 피커 뷰 해제
    [self dismissViewControllerAnimated:YES completion:^{
        NSLog(@"Image picker view dismissed");
    }];
}


@end