DeviceOrientation检查AppDelegate

Question

我在AppDelegate中创建了一个视图，我将其添加到窗口中：

[window addSubview:myView];

我希望每次回到此视图时都能检查设备方向，所以我可以对它做一些修改。我怎么能在appDelegate中做到这一点？

Answer 1

您可以在委托中实现其中一个方法，以查看应用程序何时轮换：

- (void)application:(UIApplication *)application willChangeStatusBarOrientation:(UIInterfaceOrientation)newStatusBarOrientation duration:(NSTimeInterval)duration;
- (void)application:(UIApplication *)application didChangeStatusBarOrientation:(UIInterfaceOrientation)oldStatusBarOrientation;

或者只需根据需要检查UIApplication状态栏的方向：

[[UIApplication sharedApplication] statusBarOrientation];

设备方向可能与界面方向匹配，也可能不匹配：

[[UIDevice currentDevice] orientation];

Answer 2

以下是我在didFinishLauching中第一次加载应用时首先尝试的内容

[[NSNotificationcenter defaultCenter] addObserver:self selector:@selector(orientationChanged:) name:@"UIDeviceOrientationDidChangeNotification" object: nil];

- (void)orientationChanged:(NSNotification *)notification
{
    [self performSelector:@selector(showScreen) withObject:nil afterDelay:0];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:@"UIDeviceOrientationDidChangeNotification" object:nil];
}

-(void)showScreen {

 UIDeviceOrientation deviceOrientation = [[UIDevice currentDevice] orientation];
 if (deviceOrientation == UIDeviceOrientationLandscapeLeft || UIDeviceOrientationLandscapeRight) {

  CGRect screenRect = [[UIScreen mainScreen] bounds];

 }

}

检测到横向，但screenRect显示宽度= 768，高度= 1024（我在Ipad设备中）。

Answer 3

在Apples示例中，您将通过委托方法获得通知：

- (void)orientationChanged:(NSNotification *)notification
{
    // We must add a delay here, otherwise we'll swap in the new view
    // too quickly and we'll get an animation glitch
    NSLog(@"orientationChanged");
    [self performSelector:@selector(updateLandscapeView) withObject:nil afterDelay:0];
}

然后显示纵向屏幕：

- (void)updateLandscapeView
{
PortraitView *portraitView = [[PortraitView alloc] init];
portraitView.delegate = self;
UIDeviceOrientation deviceOrientation = [UIDevice currentDevice].orientation;
if (UIDeviceOrientationIsLandscape(deviceOrientation) && !isShowingLandscapeView)
{
    [self presentModalViewController: portraitView animated:YES];
    isShowingLandscapeView = YES;
    }
else if (deviceOrientation == UIDeviceOrientationPortrait && isShowingLandscapeView)
{
    [self dismissModalViewControllerAnimated:YES];
    isShowingLandscapeView = NO;
    }
[portraitView release];
}

当然，您必须将PortraitView设计为委托类，以便按预期工作。

不是唯一的方法，但我发现它运行良好，它在苹果的例子中。我不会在Appdelegate中这样做，而是你的uiview，我不知道你的设计。