一个简单的功能,上传照片或者拍照可以用到.

//首先遵循两个代理 <UIImagePickerControllerDelegate,UINavigationControllerDelegate> //我们创建一个btn和一个imageview,btn用来触发事件调起照相机和相册的功能,imageview用来展示选取或者拍摄的图片. self.view.backgroundColor = [UIColor whiteColor]; UIButton *btn = [[UIButton alloc]initWithFrame:CGRectMake(100 , 100, 200,50)];
    btn.backgroundColor = [UIColor blackColor];
    [btn setTitle:@"ChoosePhoto" forState:UIControlStateNormal];
    [btn addTarget:self action:@selector(btnClick:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:btn];

    _imageview = [[UIImageView alloc]initWithFrame:CGRectMake(200, 200, 100, 100)];
    _imageview.backgroundColor = [UIColor lightGrayColor];
    _imageview.layer.cornerRadius = CGRectGetHeight(_imageview.bounds)/2;
    _imageview.clipsToBounds = YES;

    [self.view addSubview:_imageview]; //btn的点击事件 - (void)btnClick:(UIButton *)btn
{ //创建UIAlertController是为了让用户去选择照片来源,拍照或者相册.  UIAlertController *alertController = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:0]; UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];
    imagePickerController.delegate = self;
    imagePickerController.allowsEditing = YES; UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"从相册选取" style:(UIAlertActionStyleDefault) handler:^(UIAlertAction *action) {

        imagePickerController.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;

        [self presentViewController:imagePickerController animated:YES completion:^{}];
   }]; UIAlertAction *photoAction = [UIAlertAction actionWithTitle:@"拍照" style:(UIAlertActionStyleDefault) handler:^(UIAlertAction *action) {

        imagePickerController.sourceType = UIImagePickerControllerSourceTypeCamera;

        [self presentViewController:imagePickerController animated:YES completion:^{}];
    }]; UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"取消" style:(UIAlertActionStyleCancel) handler:^(UIAlertAction *action)
    { //这里可以不写代码  }];
    [self presentViewController:alertController animated:YES completion:nil]; //用来判断来源 Xcode中的模拟器是没有拍摄功能的,当用模拟器的时候我们不需要把拍照功能加速 if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])

    {

        [alertController addAction:okAction];
        [alertController addAction:cancelAction];
        [alertController addAction:photoAction];

    } else {
        [alertController addAction:okAction];
        [alertController addAction:cancelAction];
    }

} //这个是选取完照片后要执行的代理方法  - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info
{
    [picker dismissViewControllerAnimated:YES completion:^{}]; //选取裁剪后的图片 UIImage *image = [info objectForKey:UIImagePickerControllerEditedImage]; /* 此处info 有六个值
     * UIImagePickerControllerMediaType; // an NSString UTTypeImage)
     * UIImagePickerControllerOriginalImage;  // a UIImage 原始图片
     * UIImagePickerControllerEditedImage;    // a UIImage 裁剪后图片
     * UIImagePickerControllerCropRect;       // an NSValue (CGRect)
     * UIImagePickerControllerMediaURL;       // an NSURL
     * UIImagePickerControllerReferenceURL    // an NSURL that references an asset in the AssetsLibrary framework
     * UIImagePickerControllerMediaMetadata    // an NSDictionary containing metadata from a captured photo
     */ _imageview.image = image;

}