ios - UIPopoverController 内的 UIImagePickerController 在 iOS7 上不显示取消按钮

Question

我在 UIPopoverController 中使用 UIImagePickerController 仅从相册中选择图像。当我在运行 iOS 8 的设备上启动应用程序时，弹出窗口右上角的取消按钮通常如下所示:



但是当我在运行 iOS 7 的设备上启动应用程序时，取消按钮消失了:


我用来显示选择器的代码:

    UIImagePickerController *pickerController = [[UIImagePickerController alloc] init];
    [pickerController setSourceType:UIImagePickerControllerSourceTypePhotoLibrary];
    pickerController.delegate = self;

    _popOver = [[UIPopoverController alloc] initWithContentViewController:pickerController];
    _popOver.delegate = self;

    pickerController.navigationBar.tintColor = [UIColor redColor];//Cancel button text color
    [pickerController.navigationBar setTitleTextAttributes:@{NSForegroundColorAttributeName: [UIColor blackColor]}];// title color

    if (isImage) {
        [pickerController setMediaTypes:@[(NSString*)kUTTypeImage]];
    } else
        [pickerController setMediaTypes:@[(NSString*)kUTTypeMovie]];
    [_popOver presentPopoverFromRect:CGRectMake(1024/2, 768/2, 1, 1) inView:self.view permittedArrowDirections:0 animated:YES];

我该怎么做才能在 iOS7 上显示取消按钮？我的应用程序设计不允许用户通过点击弹出框 View 之外的任何位置来关闭弹出框。

谢谢你。

Answer 1

@JozoL 编写下面的代码这行得通

- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated {

        UINavigationItem *pickerNavBarTopItem;
        // add done button to right side of nav bar
        UIBarButtonItem *doneButton = [[UIBarButtonItem alloc] initWithTitle:@"Cancel"
                                                                       style:UIBarButtonItemStylePlain
                                                                      target:self
                                                                      action:@selector(doSomething)];

        UINavigationBar *bar = navigationController.navigationBar;
        [bar setHidden:NO];
        pickerNavBarTopItem = bar.topItem;
        pickerNavBarTopItem.rightBarButtonItem = doneButton;
    }
    -(void)doSomething{

    }