Question

我尝试按照Apple recommendations更改ViewController，将设备方向从“纵向”更改为“横向”。执行代码时，我总是收到错误消息：

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Application tried to present a nil modal view controller on target。

我无法弄清问题是什么。这是执行终止的部分（PortraitViewController的一部分）：

- (void)updateLandscapeView
{

UIDeviceOrientation deviceOrientation = [UIDevice currentDevice].orientation;

if (UIDeviceOrientationIsLandscape(deviceOrientation) && self.presentedViewController == nil){
    if (!self.resultViewLandscapeViewController){
        [self.storyboard instantiateViewControllerWithIdentifier:@"LandscapeViewController"];
        NSLog(@"LandscapeView initiated"); //this is called when device is turned
    }

        [self presentViewController:self.resultViewLandscapeViewController animated:YES completion:NULL];
//after the code above the execution is interrupted and the error message is thrown

}

else if (deviceOrientation == UIDeviceOrientationPortrait && self.presentedViewController != nil){
        [self dismissViewControllerAnimated:YES completion:NULL];
}
}

Answer 1

创建后，您实际上并未设置viewcontroller。

self.resultViewLandscapeViewController = [self.storyboard instantiateViewControllerWithIdentifier:@"LandscapeViewController"];

感谢@Arbitur指出

零模态视图控制器错误

1 个答案: