在iOS中要拍照和录制视频最简单的方式就是调用UIImagePickerController

• UIImagePickerController继承与UINavigationController，需要使用代理方法时需要同时遵守这两个协议
• 使用UIImagePickerController来选择相册图片或者拍摄图片，其实它的功能还能用来拍摄视频。

代码

//更换头像方法
- (void)changeHeaderImage
{
    UIAlertController *alert = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];

    UIImagePickerController * imagePickerController = [[UIImagePickerController alloc] init];
    imagePickerController.delegate = self;
    imagePickerController.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
    imagePickerController.allowsEditing = YES;

    UIAlertAction * defaultAction = [UIAlertAction actionWithTitle:@"拍照" style:UIAlertActionStyleDefault handler:^(UIAlertAction *  action) {
        [self selectImageFromCamera:imagePickerController];
}];

    UIAlertAction * defaultAction1 = [UIAlertAction actionWithTitle:@"从相册选择" style:UIAlertActionStyleDefault handler:^(UIAlertAction *  action) {
        [self selectImageFromAlbum:imagePickerController];
}];
    UIAlertAction * cancelAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil];

    [alert addAction:defaultAction];
    [alert addAction:cancelAction];
    [alert addAction:defaultAction1];
    [self presentViewController:alert animated:YES completion:nil];
}


//调用相机
-(void)selectImageFromCamera:(UIImagePickerController *)imagePickerVC
{
    imagePickerVC.sourceType = UIImagePickerControllerSourceTypeCamera;
    //相机类型（拍照、录像...）字符串需要做相应的类型转换
    imagePickerVC.mediaTypes = @[(NSString *)kUTTypeImage];

    //设置摄像头模式(拍照，录制视频)
    imagePickerVC.cameraCaptureMode = UIImagePickerControllerCameraCaptureModePhoto;
    [self presentViewController:imagePickerVC animated:YES completion:nil];
}


//调用系统相册
-(void)selectImageFromAlbum:(UIImagePickerController *)imagePickerVC
{
    imagePickerVC.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    [self presentViewController:imagePickerVC animated:YES completion:nil];
}


//适用获取所有媒体资源，只需判断资源类型
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info{
    NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];
    //判断资源类型
    if ([mediaType isEqualToString:(NSString *)kUTTypeImage]){
       //如果是图片
        UIImage *image = info[UIImagePickerControllerEditedImage];
        [self saveImage:image withName:headerImageName];
         NSIndexPath * index = [NSIndexPath indexPathForRow:0 inSection:0];
         [_backTableView reloadRowsAtIndexPaths:@[index] withRowAnimation:UITableViewRowAnimationFade];
    }
    [picker dismissViewControllerAnimated:YES completion:nil];
}


// 保存图片至沙盒（应该是提交后再保存到沙盒,下次直接去沙盒取）
- (void) saveImage:(UIImage *)currentImage withName:(NSString *)imageName
{
    NSData *imageData = UIImageJPEGRepresentation(currentImage, 0.5);
    // 获取沙盒目录
    NSString *headImagePath = [kPathDocument stringByAppendingPathComponent:imageName];
    // 将图片写入文件
    [imageData writeToFile:headImagePath atomically:NO];
}