ios - 当我 Handlebars 机放平时，UIDevice 方向不断在 UIDeviceOrientationPortrait 和 UIDeviceOrientationLandscapeRight 之间翻转

Question

当我将手机平放时，我对设备方向值感到非常困惑。我为 UIDeviceOrientationDidChangeNotification 注册了一个观察者，并调用 beginGenerateDeviceOrientationNotifications 来观察设备方向的变化。一切正常，直到我将手机平放在桌面上。

这是我的项目中的代码:

- (void)deviceDidRotate:(NSNotification *)notification
{
    UIDevice *currentDevice = [UIDevice currentDevice];
    NSLog(@"Orientation: %d", currentDevice.orientation);
}

日志给了我这个:

2013-12-29 12:14:28.121 MyProject[1140:60b] Orientation: 5
2013-12-29 12:14:28.764 MyProject[1140:60b] Orientation: 1
2013-12-29 12:14:31.609 MyProject[1140:60b] Orientation: 4
2013-12-29 12:14:33.377 MyProject[1140:60b] Orientation: 1
2013-12-29 12:14:33.574 MyProject[1140:60b] Orientation: 4
2013-12-29 12:14:33.770 MyProject[1140:60b] Orientation: 1
2013-12-29 12:14:33.868 MyProject[1140:60b] Orientation: 4
2013-12-29 12:14:34.065 MyProject[1140:60b] Orientation: 1
2013-12-29 12:14:34.164 MyProject[1140:60b] Orientation: 4
2013-12-29 12:14:34.455 MyProject[1140:60b] Orientation: 1
2013-12-29 12:14:34.555 MyProject[1140:60b] Orientation: 4
    repeating...

前 5 个相当合理，因为我已将手机正面朝上，但 1s(代表 UIDeviceOrientationPortrait)和 4s(代表 UIDeviceOrientationLandscapeRight)相当令人困惑.

我的问题是如何解决这个问题？

Answer 1

我遇到了同样的问题，下面的解决方案解决了这个问题:

在每个 viewController 中添加以下方法(根据您的首选方向)

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {

    return (interfaceOrientation == UIInterfaceOrientationLandscapeLeft);
}

- (BOOL)shouldAutorotate {

    return NO;
}

- (NSUInteger)supportedInterfaceOrientations {

    return UIInterfaceOrientationMaskLandscape;
}

- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation {

    return UIInterfaceOrientationLandscapeLeft;
}

在 AppDelegate 中以及 didFinishLaunchingWithOptions

中的以下代码行

[[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(preferredInterfaceOrientationForPresentation) name:@"UIDeviceOrientationDidChangeNotification" object:nil];