Question

我有一个UISplitViewController UISplitViewControllerDelegate，其代理方法如下：

splitViewController：willHideViewController：withBarButtonItem：forPopoverController：

当在Portrait中启动iPad时，我希望可以看到SplitView中的Popover。我怎么能这样做？

我尝试过以下代码：

- (void)splitViewController:(UISplitViewController *)svc
     willHideViewController:(UIViewController *)aViewController
          withBarButtonItem:(UIBarButtonItem *)barButtonItem
       forPopoverController:(UIPopoverController *)pc
{
    //setting the barButtonItem in the toolbar in the detail view.

    [pc presentPopoverFromBarButtonItem:barButtonItem permittedArrowDirections:UIPopoverArrowDirectionAny animated:NO];
}

但上面的代码给出了以下错误：

由于未捕获的异常'NSInvalidArgumentException'而终止应用程序，原因：' - [UIPopoverController presentPopoverFromRect：inView：allowedArrowDirections：animated：]：无法从没有窗口的视图中显示弹出窗口。'

Answer 1

只有一个问题，错误的地方调用presentPopover方法，splitViewController：* WillHide * ViewController .......所以，barButtonItem存在但屏幕上不存在。我使用下一个代码，它对我有用。对于处理所有情况，你需要使用2种方法。

- (void)viewDidAppear:(BOOL)animated
{
    if ([[UIDevice currentDevice] orientation] == UIDeviceOrientationPortrait || [[UIDevice currentDevice] orientation] == UIDeviceOrientationPortraitUpsideDown) {
        if (self.view.window != nil) {
            [_masterPopoverController presentPopoverFromRect:CGRectMake(0, 0, 1, 1) inView:self.view permittedArrowDirections:UIPopoverArrowDirectionUp animated:NO];
        }
    }
    [super viewDidAppear:animated];
}

和

-(void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation
{
    if (fromInterfaceOrientation == UIDeviceOrientationLandscapeLeft || fromInterfaceOrientation == UIDeviceOrientationLandscapeRight) {
        if (self.view.window != nil) {
            [_masterPopoverController presentPopoverFromRect:CGRectMake(0, 0, 1, 1) inView:self.view permittedArrowDirections:UIPopoverArrowDirectionUp animated:NO];
        }
    }
}

UISplitViewController：如何呈现popover？

1 个答案: