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iOS开发之监听键盘高度的变化

最近做的项目中，有一个类似微博中的评论转发功能，屏幕底端有一个输入框用textView来做，当textView成为第一响应者的时候它的Y值随着键盘高度的改变而改变，保证textView紧贴着键盘，但又不会被键盘挡住。

下面是我实现的方法：（利用通知）

// 键盘通知

// 键盘的frame发生改变时发出的通知（位置和尺寸）

// UIKeyboardWillChangeFrameNotification

// UIKeyboardDidChangeFrameNotification

// 键盘显示时发出的通知

// UIKeyboardWillShowNotification

// UIKeyboardDidShowNotification

// 键盘隐藏时发出的通知

// UIKeyboardWillHideNotification

// UIKeyboardDidHideNotification

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillChangeFrame:) name:UIKeyboardWillChangeFrameNotification object:nil];//在这里注册通知

下面是监听通知：

pragma mark - 监听方法

/**

键盘的frame发生改变时调用（显示、隐藏等）
*/
(void)keyboardWillChangeFrame:(NSNotification *)notification

{

// if (self.picking) return;

/**

notification.userInfo = @{

// 键盘弹出/隐藏后的frame

UIKeyboardFrameEndUserInfoKey = NSRect: {{0, 352}, {320, 216}},

// 键盘弹出/隐藏所耗费的时间

UIKeyboardAnimationDurationUserInfoKey = 0.25,

// 键盘弹出/隐藏动画的执行节奏（先快后慢，匀速）

UIKeyboardAnimationCurveUserInfoKey = 7

}

*/

NSDictionary *userInfo = notification.userInfo;

// 动画的持续时间doubleduration = [userInfo[UIKeyboardAnimationDurationUserInfoKey] doubleValue];

// 键盘的frameCGRect keyboardF = [userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];

// 执行动画

[UIView animateWithDuration:duration animations:^{

// 工具条的Y值 == 键盘的Y值 - 工具条的高度

if(keyboardF.origin.y > self.view.height) { // 键盘的Y值已经远远超过了控制器view的高度

self.toolbar.y = self.view.height - self.toolbar.height;//这里的

self.toolbar就是我的输入框。
```
}else{     self.toolbar.y = keyboardF.origin.y - self.toolbar.height; }
```
}];}

当然，这里我为UIView写了一个类别，实现如下：.h文件中声明

@interfaceUIView (Extension)

@property(nonatomic, assign) CGFloat x;

@property(nonatomic, assign) CGFloat y;

@property(nonatomic, assign) CGFloat width;

@property(nonatomic, assign) CGFloat height;

@property(nonatomic, assign) CGFloat centerX;

@property(nonatomic, assign) CGFloat centerY;

@property(nonatomic, assign) CGSize size;

@property(nonatomic, assign) CGPoint origin;

@end

.m文件中实现（重写setter 和 getter）

@implementationUIView (Extension)

(void)setX:(CGFloat)x

{

CGRect frame = self.frame;

frame.origin.x = x;

self.frame = frame;

}
(void)setY:(CGFloat)y

{

CGRect frame = self.frame;

frame.origin.y = y;

self.frame = frame;

}
(CGFloat)x

{

returnself.frame.origin.x;

}
(CGFloat)y

{

returnself.frame.origin.y;

}
(void)setCenterX:(CGFloat)centerX

{

CGPoint center = self.center;

center.x = centerX;

self.center = center;

}
(CGFloat)centerX

{

returnself.center.x;

}
(void)setCenterY:(CGFloat)centerY

{

CGPoint center = self.center;

center.y = centerY;

self.center = center;

}
(CGFloat)centerY

{

returnself.center.y;

}
(void)setWidth:(CGFloat)width

{

CGRect frame = self.frame;

frame.size.width = width;

self.frame = frame;

}
(void)setHeight:(CGFloat)height

{

CGRect frame = self.frame;

frame.size.height = height;

self.frame = frame;

}
(CGFloat)height

{

returnself.frame.size.height;

}
(CGFloat)width

{

returnself.frame.size.width;

}
(void)setSize:(CGSize)size

{

CGRect frame = self.frame;

frame.size = size;

self.frame = frame;

}
(CGSize)size

{

returnself.frame.size;

}
(void)setOrigin:(CGPoint)origin

{

CGRect frame = self.frame;

frame.origin = origin;

self.frame = frame;

}
(CGPoint)origin

{

returnself.frame.origin;

}

@end

有需要的朋友可以直接用