ios - 处理旋转时更改 iOS 键盘布局

Question

根据设备的方向，我的键盘有两种略有不同的布局。当我第一次加载键盘时，它看起来不错。这是纵向版本:

初始约束设置发生在 -viewDidLoad(属于 UIInputViewController 子类)

portraitConstraints = [self constraintsForOrientation:UIInterfaceOrientationPortrait];
landscapeConstraints = [self constraintsForOrientation:UIInterfaceOrientationLandscapeRight];

[self.view addConstraints:portraitConstraints];
[self.view addConstraints:landscapeConstraints];

if ([UIScreen mainScreen].bounds.size.width < [UIScreen mainScreen].bounds.size.height) {
    [NSLayoutConstraint deactivateConstraints:landscapeConstraints];
} else {
    [NSLayoutConstraint deactivateConstraints:portraitConstraints];
}

这部分工作正常，因为无论初始方向如何，它都能正确加载。但是，一旦我旋转设备，一切都出错了。

然后回到纵向:

作为引用，正确的横向版本如下所示:

我更新了 -updateViewConstraints 中的约束，如下所示:

- (void)updateViewConstraints {
    if ([UIScreen mainScreen].bounds.size.width < [UIScreen mainScreen].bounds.size.height) {
        [NSLayoutConstraint deactivateConstraints:landscapeConstraints];
        [NSLayoutConstraint activateConstraints:portraitConstraints];
    } else {
        [NSLayoutConstraint deactivateConstraints:portraitConstraints];
        [NSLayoutConstraint activateConstraints:landscapeConstraints];
    }

    [super updateViewConstraints];
}

似乎在 View 更改后，它突然占据了比全屏更多的空间，而不仅仅是键盘区域。有什么办法可以解决这个问题吗？谢谢。

Answer 1

这个问题似乎与以某种方式隐式覆盖包含键盘的 View 的高度有关。虽然我没有看到任何会强制调整容器 View 大小的内容，但显式设置容器 View 的高度得到了良好的、可重现的结果。

我想到了从 Apple's App Extension Programming Guide: Custom Keyboard 手动限制键盘高度的想法.

具体来说，相关信息是这样的:

You can adjust the height of your custom keyboard’s primary view using Auto Layout. By default, a custom keyboard is sized to match the system keyboard, according to screen size and device orientation. A custom keyboard’s width is always set by the system to equal the current screen width. To adjust a custom keyboard’s height, change its primary view's height constraint.

The following code lines show how you might define and add such a constraint:

CGFloat _expandedHeight = 500;
NSLayoutConstraint *_heightConstraint = 
[NSLayoutConstraint constraintWithItem: self.view 
                             attribute: NSLayoutAttributeHeight 
                             relatedBy: NSLayoutRelationEqual 
                                toItem: nil 
                             attribute: NSLayoutAttributeNotAnAttribute 
                            multiplier: 0.0 
                              constant: _expandedHeight];
[self.view addConstraint: _heightConstraint];

NOTE

In iOS 8.0, you can adjust a custom keyboard’s height any time after its primary view initially draws on screen.

以下是基于此信息的模板答案中的重要方法:

- (void)updateViewConstraints {
    if (self.keyboardHeightConstraint == nil) {
        // Just starting with SOME value for the height
        self.keyboardHeightConstraint =
        [NSLayoutConstraint constraintWithItem:self.view
                                     attribute:NSLayoutAttributeHeight
                                     relatedBy:NSLayoutRelationEqual
                                        toItem:nil
                                     attribute:NSLayoutAttributeNotAnAttribute
                                    multiplier:0.0f
                                      constant:500.0f];
        [self.view addConstraint:self.keyboardHeightConstraint];
    }
    // Obviously, these values will be changed based on device AND orientation
    // These are bogus values...
    if ([UIScreen mainScreen].bounds.size.width < [UIScreen mainScreen].bounds.size.height) {
        self.keyboardHeightConstraint.constant  = 300.0f;
        [NSLayoutConstraint deactivateConstraints:self.landscapeConstraints];
        [NSLayoutConstraint activateConstraints:self.portraitConstraints];
    } else {
        self.keyboardHeightConstraint.constant  = 400.0f;
        [NSLayoutConstraint deactivateConstraints:self.portraitConstraints];
        [NSLayoutConstraint activateConstraints:self.landscapeConstraints];
    }
    [super updateViewConstraints];
}