UI_UIImagePickerController（讀取圖片）

創建圖片

#pragma mark - 創建 photoImageView
- (void)createphotoImageView
{

    self.photoImageView = [[UIImageView alloc] initWithFrame:CGRectMake(10, 70, 320, 390)];
    self.photoImageView.backgroundColor = [UIColor magentaColor];

    // 打開交互 實現手勢輕拍
    self.photoImageView.userInteractionEnabled = YES;

    [self addSubview:self.photoImageView];
}

實現代理（3個）

@interface RootViewController () <UIActionSheetDelegate, UIImagePickerControllerDelegate, UINavigationControllerDelegate>

// 綁定手勢
- (void)viewDidLoad {
    [super viewDidLoad];

    // 輕拍手勢
    UITapGestureRecognizer *tapGR = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapGRAction:)];

    [self.rootView.photoImageView addGestureRecognizer:tapGR];

}

#pragma mark - 實現手勢操作
- (void)tapGRAction:(UITapGestureRecognizer *)sender
{
    NSLog(@"tap it");

    // 底部彈出的控件
    UIActionSheet *sheet = [[UIActionSheet alloc] initWithTitle:@"請選擇圖片" delegate:self cancelButtonTitle:@"取消" destructiveButtonTitle:nil otherButtonTitles:@"從相冊選取",@"拍照", nil];

    // 在什麼地方展示
    [sheet showInView:self.rootView];
}

#pragma mark - 輕拍手勢中 action 代理方法
- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex
{
    NSLog(@"%ld", buttonIndex);

    // 從相冊選取或拍照
    if (actionSheet.firstOtherButtonIndex == buttonIndex) {
        NSLog(@"相冊");

        // 相冊是否可用
        if ([UIImagePickerController isSourceTypeAvailable:(UIImagePickerControllerSourceTypePhotoLibrary)]) {

            UIImagePickerController *imagePickerVC = [[UIImagePickerController alloc] init];

            // 通過代理方法拿到圖片
            imagePickerVC.delegate = self;
            // 可以對圖片進行編輯（對應代理方法）
            imagePickerVC.allowsEditing = YES;

            // 指定 pickVC 從相冊選取
            imagePickerVC.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

            // 模態推出
            [self presentViewController:imagePickerVC animated:YES completion:nil];
        }

    } else if (buttonIndex == actionSheet.firstOtherButtonIndex + 1)
    {
        NSLog(@"拍照");

        if ([UIImagePickerController isSourceTypeAvailable:(UIImagePickerControllerSourceTypeCamera)]) {

            UIImagePickerController *imagePickerVC = [[UIImagePickerController alloc] init];

            // 通過代理方法拿到圖片
            imagePickerVC.delegate = self;
            // 可以對圖片進行編輯（對應代理方法）
            imagePickerVC.allowsEditing = YES;

            // 指定 pickVC 從相機選取
            imagePickerVC.sourceType = UIImagePickerControllerSourceTypeCamera;

            // 模態推出
            [self presentViewController:imagePickerVC animated:YES completion:nil];
        }
    }
}

#pragma mark - 實現代理方法（拿到圖片）
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    [picker dismissViewControllerAnimated:YES completion:nil];

    UIImage *image =  [info objectForKey:UIImagePickerControllerEditedImage];

    self.rootView.photoImageView.image = image;
}

#pragma mark - 取消按鈕的代理方法
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
    // 一般在 rightButton
    [picker dismissViewControllerAnimated:YES completion:nil];
}