iOS开发之监听键盘高度的变化 分类: ios技术 2015-04-21 12:04 233人阅读 评论(0) 收藏

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)

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//
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:

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#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frame
    CGRect
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<span
style="background-color: rgb(240, 240, 240);">self.toolbar就是我的输入框。</span>
 
        }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

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@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)

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@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

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