似乎当我的应用程序加载时，它不知道当前的方向：
UIInterfaceOrientation orientation = [[UIDevice currentDevice] orientation];
if (orientation == UIDeviceOrientationPortrait) {
NSLog(@"portrait");// only works after a rotation, not on loading app
}
当我旋转设备后，方向就正确了。但是当我加载应用程序而未改变方向时，使用 [[UIDevice currentDevice] orientation] 似乎无法知道当前方向。
在我第一次加载应用程序时，是否有其他方法可以检查此问题？
试试这个
[[UIApplication sharedApplication] statusBarOrientation];
或者在应用程序委托中实现这个
(NSUInteger)application:(UIApplication *)application supportedInterfaceOrientationsForWindow:(UIWindow *)window
{
UIDeviceOrientation orientation = [[UIDevice currentDevice] orientation];
}
它有效
试试这个。对我来说很有效。在didfinishedlaunch方法中，有时无法检测到设备方向。它默认为纵向。所以，我使用了检查状态栏方向的方法。我测试了这段代码，将其放在appdeleget的didfinishedlaunch方法中。
UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;
if(orientation == 0) {//Default orientation
//UI is in Default (Portrait) -- this is really a just a failsafe.
NSLog("for portrait");
}else if(orientation == UIInterfaceOrientationPortrait || orientation == UIInterfaceOrientationPortraitUpsideDown)
{
NSLog("portrait");
}else if(orientation == UIInterfaceOrientationLandscapeLeft || orientation == UIInterfaceOrientationLandscapeRight)
{
NSLog("Landscap");
}
- (void)splitViewController:(UISplitViewController *)svc willHideViewController:(UIViewController *)aViewController withBarButtonItem:(UIBarButtonItem *)barButtonItem forPopoverController: (UIPopoverController *)pc { NSlog(@"portrait");}
横向布局：
- (void)splitViewController:(UISplitViewController *)svc willShowViewController:(UIViewController *)aViewController invalidatingBarButtonItem:(UIBarButtonItem *)barButtonItem{ NSlog(@"landscape");}
这个总是在加载时起作用。
这是真正的答案。当应用程序启动时，它的方向是未知的。它使用shouldAutorotateToInterfaceOrientation和supportedInterfaceOrientations来决定选择哪个方向。
看我如何在iPhone 5.0模拟器中启动一个示例应用程序，并使用下面的代码和“支持的界面方向”旋转它，包括所有4个可能的方向：
20:44:08.218 RotationTestApp Supported orientation: Portrait
20:44:08.222 RotationTestApp Supported orientation: Portrait (upside-down)
20:44:08.225 RotationTestApp Supported orientation: Landscape (home button on the right)
20:44:08.225 RotationTestApp Supported orientation: Landscape (home button on the left)
20:44:08.226 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (current device orientation: UIDeviceOrientationUnknown, interface orientation wants: UIInterfaceOrientationPortrait)
20:44:08.237 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (current device orientation: UIDeviceOrientationUnknown, interface orientation wants: UIInterfaceOrientationPortrait)
20:44:08.239 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (current device orientation: UIDeviceOrientationUnknown, interface orientation wants: UIInterfaceOrientationPortrait)
20:44:08.240 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (current device orientation: UIDeviceOrientationUnknown, interface orientation wants: UIInterfaceOrientationPortrait)
20:44:09.817 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (device orientation: UIDeviceOrientationLandscapeLeft)
20:44:09.833 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (device orientation: UIDeviceOrientationLandscapeLeft)
20:44:11.030 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (device orientation: UIDeviceOrientationPortraitUpsideDown)
20:44:11.040 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (device orientation: UIDeviceOrientationPortraitUpsideDown)
20:44:12.599 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (device orientation: UIDeviceOrientationLandscapeRight)
20:44:12.609 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (device orientation: UIDeviceOrientationLandscapeRight)
20:44:13.301 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (device orientation: UIDeviceOrientationPortraitUpsideDown)
我看过很多代码片段，但它们都不够通用（iPad和iPhone，iOS 5.0+）。
与其试错，不如将以下内容放在您的根视图控制器中：
#define ToNSString_BEGIN(T) \
NSString* T##ToNSString(T valueParameter) { \
switch (valueParameter) {
#define ToNSString_VALUE(value) \
case value: return @#value
#define ToNSString_END(T) \
} \
return @"(unknown)"; \
}
// NSString* UIInterfaceOrientationToNSString(UIInterfaceOrientation);
ToNSString_BEGIN(UIInterfaceOrientation);
ToNSString_VALUE(UIInterfaceOrientationPortrait); // 1
ToNSString_VALUE(UIInterfaceOrientationPortraitUpsideDown); // 2
ToNSString_VALUE(UIInterfaceOrientationLandscapeLeft); // 3
ToNSString_VALUE(UIInterfaceOrientationLandscapeRight); // 4
ToNSString_END (UIInterfaceOrientation);
// NSString* UIDeviceOrientationToNSString(UIDeviceOrientation);
ToNSString_BEGIN(UIDeviceOrientation);
ToNSString_VALUE(UIDeviceOrientationUnknown); // 0
ToNSString_VALUE(UIDeviceOrientationPortrait); // 1
ToNSString_VALUE(UIDeviceOrientationPortraitUpsideDown); // 2
ToNSString_VALUE(UIDeviceOrientationLandscapeLeft); // 3
ToNSString_VALUE(UIDeviceOrientationLandscapeRight); // 4
ToNSString_VALUE(UIDeviceOrientationFaceUp); // 5
ToNSString_VALUE(UIDeviceOrientationFaceDown); // 6
ToNSString_END (UIDeviceOrientation);
// Change this custom method to alter auto-rotation behavior on all supported iOS versions and platforms.
- (BOOL)allowAutoRotate:(UIInterfaceOrientation)interfaceOrientation
{
NSUInteger interfaceOrientationAsMask = (1<<interfaceOrientation);
return interfaceOrientationAsMask & [self supportedInterfaceOrientations];
}
// Reads from the project's-Info.plist
- (NSUInteger)supportedInterfaceOrientations
{
static NSUInteger orientationsResult;
if (!orientationsResult) {
NSArray *supportedOrientations = [[NSBundle mainBundle] objectForInfoDictionaryKey:@"UISupportedInterfaceOrientations"];
for (id orientationString in supportedOrientations) {
if ([orientationString isEqualToString:@"UIInterfaceOrientationPortrait"]) {
orientationsResult |= UIInterfaceOrientationMaskPortrait;
NSLog(@"Supported orientation: Portrait");
} else if ([orientationString isEqualToString:@"UIInterfaceOrientationPortraitUpsideDown"]) {
orientationsResult |= UIInterfaceOrientationMaskPortraitUpsideDown;
NSLog(@"Supported orientation: Portrait (upside-down)");
} else if ([orientationString isEqualToString:@"UIInterfaceOrientationLandscapeRight"]) {
orientationsResult |= UIInterfaceOrientationMaskLandscapeRight;
NSLog(@"Supported orientation: Landscape (home button on the left)");
} else if ([orientationString isEqualToString:@"UIInterfaceOrientationLandscapeLeft"]) {
orientationsResult |= UIInterfaceOrientationMaskLandscapeLeft;
NSLog(@"Supported orientation: Landscape (home button on the right)");
} else {
NSLog(@"Unrecognized orientation '%@' in mainBundle plist, key UISupportedInterfaceOrientations", orientationString);
}
}
}
return orientationsResult;
}
// iOS 6+ (not yet used in 6.0.1)
- (BOOL)shouldAutorotate
{
UIDeviceOrientation interfaceOrientationFromDevice = [UIDevice currentDevice].orientation;
BOOL result = [self allowAutoRotate:interfaceOrientationFromDevice];
NSString *currentDeviceOrientation = UIDeviceOrientationToNSString(interfaceOrientationFromDevice);
NSLog(@"shouldAutorotate: %s (current orientation %@)", result ? "YES" : "NO", currentDeviceOrientation);
return result;
}
// iOS 2.0 - 5.1 (iOS 6+ deprecated, 6.0.1 still works)
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
NSString* orientationString;
UIDeviceOrientation interfaceOrientationFromDevice = [UIDevice currentDevice].orientation;
if ((int)interfaceOrientation != (int)interfaceOrientationFromDevice) {
orientationString = [NSString stringWithFormat:@"current device orientation: %@, interface orientation wants: %@",
UIDeviceOrientationToNSString(interfaceOrientationFromDevice),
UIInterfaceOrientationToNSString(interfaceOrientation)
];
} else {
orientationString = [NSString stringWithFormat:@"device orientation: %@", UIDeviceOrientationToNSString(interfaceOrientationFromDevice)
];
}
BOOL result = [self allowAutoRotate:interfaceOrientation];
NSLog(@"shouldAutorotateToInterfaceOrientation: %s (%@)",
result ? "YES" : "NO",
orientationString);
return result;
}
仍有一个令人讨厌的问题，即Segue动画不使用当前方向。 我猜想，对每个VC进行子类化并在推送时放置一些方向/在弹出时通知代理可能是解决问题的方法。
还有重要的一点：
我仍然使用这个可用的代码片段来适配iPhone 4：
-(void)deviceOrientationDidChange:(NSNotification *)notification{
//Obtaining the current device orientation
UIDeviceOrientation orientation = [[UIDevice currentDevice] orientation];
int value = 0;
if(orientation == UIDeviceOrientationPortrait)
{
value = 0;
}else if(orientation == UIDeviceOrientationLandscapeLeft)
{
value = 90;
}else if(orientation == UIDeviceOrientationLandscapeRight)
{
value = -90;
}
CGAffineTransform cgCTM = CGAffineTransformMakeRotation(DEGREES_TO_RADIANS(value));
[photoImageView setTransform:cgCTM];
}
以上所有人都发表了非常有效的答案，但是作为更新：苹果公司的看法是：您应该使用UIStatusBar方向来读取设备的当前方向：
您可以通过在viewDidLoad方法中使用int值来检查设备的当前方向，例如：
int orientationType = [[UIDevice currentDevice] orientation];
IF语句在检测到方向后调用一个方法，以此类推。