轻松创建一个能够响应用户键盘事件的类。
之前
- (void)registerMyClass {
NSNotificationCenter *defaultCenter = [NSNotificationCenter defaultCenter];
[defaultCenter addObserver:self selector:@selector(didShow:) name:UIKeyboardDidShowNotification object:nil];
[defaultCenter addObserver:self selector:@selector(didHide:) name:UIKeyboardDidHideNotification object:nil];
[defaultCenter addObserver:self selector:@selector(willShow:) name:UIKeyboardWillShowNotification object:nil];
[defaultCenter addObserver:self selector:@selector(willHide:) name:UIKeyboardWillHideNotification object:nil];
[defaultCenter addObserver:self selector:@selector(didChangeFrame:) name:UIKeyboardDidChangeFrameNotification object:nil];
[defaultCenter addObserver:self selector:@selector(willChangeFrame:) name:UIKeyboardWillChangeFrameNotification object:nil];
}
// No autocompletion here, you have to type the methods' name…
- (void)didShow:(NSNotification *)notification {
...
}
- (void)willShow:(NSNotification *)notification {
...
}
- (void)didHide:(NSNotification *)notification {
...
}
- (void)willHide:(NSNotification *)notification {
...
}
- (void)didChangeFrame:(NSNotification *)notification {
...
}
- (void)willChangeFrame:(NSNotification *)notification {
...
}
之后
- (void)registerMyClass {
[[KWKeyboardListener sharedInstance] addKeyboardEventsListener:self withHandler:^(CGRect keyboardFrame, BOOL opening, BOOL closing) {
// This block will get called when the keyboard *will* show/hide/change frame
}];
}您也可以让您的类遵循 KWKeyboardEventsListener 协议，调用 [[KWKeyboardListener sharedInstance] addKeyboardEventsListener:self] 并实现您希望的方法。这种方法与 NSNotificationCenter 相比的优势在于，您不需要为每个希望响应的事件分别注册您的类，而且由于协议的存在，通过自动完成功能，您只需简单开始输入 - (void)keyboard 并查看支持的事件列表，这些事件有：
- (void)keyboardWillShowWithInfos:(NSDictionary *)infos;
- (void)keyboardWillHideWithInfos:(NSDictionary *)infos;
- (void)keyboardDidShowWithInfos:(NSDictionary *)infos;
- (void)keyboardDidHideWithInfos:(NSDictionary *)infos;
- (void)keyboardWillChangeFrameWithInfos:(NSDictionary *)infos;
- (void)keyboardDidChangeFrameWithInfos:(NSDictionary *)infos;信息只是您通常会从常规 NSNotification 收到的 userInfo。您可以使用常规通知键获取事件的相关信息，如 UIKit 中定义的。
UIKIT_EXTERN NSString *const UIKeyboardFrameBeginUserInfoKey NS_AVAILABLE_IOS(3_2); // NSValue of CGRect
UIKIT_EXTERN NSString *const UIKeyboardFrameEndUserInfoKey NS_AVAILABLE_IOS(3_2); // NSValue of CGRect
UIKIT_EXTERN NSString *const UIKeyboardAnimationDurationUserInfoKey NS_AVAILABLE_IOS(3_0); // NSNumber of double
UIKIT_EXTERN NSString *const UIKeyboardAnimationCurveUserInfoKey NS_AVAILABLE_IOS(3_0); // NSNumber of NSUInteger 此外，KWKeyboardListener 单例在类加载时实例化，因此您无需做任何事情，这可以让您从任何地方获取应用中键盘的当前状态，使用其 keyboardVisible 布尔属性。
pod 'KWKeyboardListener', '~>1.0'