在UIKeyboardWillShowNotification /上，iOS键盘高度返回不正确

Question

我正在尝试在显示键盘时向上滚动文本视图。我正试图在https://developer.apple.com/library/ios/documentation/StringsTextFonts/Conceptual/TextAndWebiPhoneOS/KeyboardManagement/KeyboardManagement.html关注Apple自己的教程。我使用autolayout而不是滚动视图和框架，但总体思路是相同的（订阅键盘通知，并相应地设置布局约束）。但是，当我显示键盘时，文本视图和键盘之间存在间隙:(这是来自土耳其语键盘的屏幕截图，但所有安装的键盘中都存在标有红色的相同间隙，包括自定义键盘）。 （iPhone 6 Plus的屏幕截图，但问题也出现在其他屏幕尺寸上）

我已经看过can't get correct value of keyboard height in iOS8而我已尝试同时使用UIKeyboardFrameEndUserInfoKey和UIKeyboardFrameBeginUserInfoKey，但它们都会导致相同的差距。我已尝试附加UIKeyboardWillShowNotification和UIKeyboardDidShowNotification，但我仍然有同样的差距。我认为差距与iOS 8上某些键盘上的建议有关，但是当建议不存在时，它不应该通过建议报告键盘大小。

这是我的代码：

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    [self registerForKeyboardNotifications];
}

- (void)registerForKeyboardNotifications
{
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWillBeShown:)
                                                 name:UIKeyboardWillShowNotification object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWillBeHidden:)
                                                 name:UIKeyboardWillHideNotification object:nil];

}

// Called when the UIKeyboardDidShowNotification is sent.
- (void)keyboardWillBeShown:(NSNotification*)aNotification
{
    NSDictionary* info = [aNotification userInfo];
    CGRect kb = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];

    float height = kb.size.height;
    sendZoneBottomConstraint.constant = height;
    [UIView animateWithDuration:.2 animations:^{
        [self.view layoutIfNeeded];
    }];
}

// Called when the UIKeyboardWillHideNotification is sent
- (void)keyboardWillBeHidden:(NSNotification*)aNotification
{
    sendZoneBottomConstraint.constant = 0;
    [UIView animateWithDuration:.2 animations:^{
        [self.view layoutIfNeeded];
    }];
}

sendZoneBottomConstraint是底部布局指南底部最底部视图的底部间距。

更新：我已尝试将键盘矩形从窗口坐标更改为我的视图坐标，但它没有改变任何内容。这是我试过的：

CGRect kb = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
kb = [self.view.window convertRect:kb toView:self.view];
float height = kb.size.height;

更新，第2卷：我也见过iOS 8 Orientation change: Keyboard frame does not display correctly，但我在iPhone 5s iOS 7.1模拟器上遇到了这个问题，所以它也是不是iOS 8唯一的问题。 我怎么解决这个问题？我绝对不想在iOS 8世界中硬编码任何键盘高度值。

更新，第3卷：我还尝试使用英文键盘打开和关闭建议。它仍然出现在键盘的总大小上，所以它与建议/自动完成视图无关：

Answer 1

也许您正在使用标签栏控制器，如果是，那么当您在键盘显示后边缘视图时，计算边距底部没有标签栏高度。

您可以使用以下方法找到标签栏高度：

self.tabBarController?.tabBar.frame.height

Answer 2

要进行可靠的键盘高度计算，可以使用以下命令：

注意：我为此解决方案从IQKeyboard借用了一些逻辑。

CGRect kbFrame = [[aNotification userInfo][UIKeyboardFrameEndUserInfoKey] CGRectValue];

CGRect screenSize = [[UIScreen mainScreen] bounds];

CGRect intersectRect = CGRectIntersection(kbFrame, screenSize);//Calculating actual keyboard displayed size, keyboard frame may be different when hardware keyboard is attached (Bug ID: #469) (Bug ID: #381)

CGSize kbSize;
if (CGRectIsNull(intersectRect)) {
    kbSize = CGSizeMake(screenSize.size.width, 0);
} else {
    kbSize = intersectRect.size;
}

//

UIViewController *rootViewController = [UIApplication sharedApplication].keyWindow.rootViewController;
while (rootViewController) {
    if ([rootViewController isKindOfClass:[UINavigationController class]]) {
        UINavigationController *navigationController = (UINavigationController *)rootViewController;
        UIViewController *nextRootViewController = [[navigationController viewControllers] lastObject];
        if (nextRootViewController) {
            rootViewController = nextRootViewController;
            continue;
        } else {
            break;
        }
    }
    if ([rootViewController isKindOfClass:[UITabBarController class]]) {
        UITabBarController *tabBarController = (UITabBarController *)rootViewController;
        UIViewController *nextRootViewController = tabBarController.selectedViewController;
        if (nextRootViewController) {
            rootViewController = nextRootViewController;
            continue;
        } else {
            break;
        }
    }
    if (!rootViewController.presentedViewController) {
        break;
    }
    rootViewController = (UIViewController *)rootViewController.presentedViewController;
}

//

CGFloat navigationBarAreaHeight = [[UIApplication sharedApplication] statusBarFrame].size.height + rootViewController.navigationController.navigationBar.frame.size.height;
CGFloat layoutAreaHeight = rootViewController.view.layoutMargins.top;

CGFloat topLayoutGuide = MAX(navigationBarAreaHeight, layoutAreaHeight);

CGFloat bottomLayoutGuide = rootViewController.view.layoutMargins.bottom;

float magicNumber = 5;//Apple Constant

//

float keyboardHeight = kbSize.height-topLayoutGuide-bottomLayoutGuide+magicNumber;