iOS技巧——即时监听键盘高度

来源：互联网发布：windows arp a 编辑：程序博客网时间：2024/05/17 08:04

需求：带输入框的view显示在界面最下端，当弹出键盘时，view要在键盘的上面，并且随着输入法的不同即时改变高度。

- (void)viewDidLoad{    [super viewDidLoad];    // Do any additional setup after loading the view from its nib.        //使用NSNotificationCenter 键盘出现时    [[NSNotificationCenter defaultCenter] addObserver:self                                             selector:@selector(keyboardWillAppear:)                                                 name:UIKeyboardDidShowNotification object:nil];        //使用NSNotificationCenter 键盘隐藏时    [[NSNotificationCenter defaultCenter] addObserver:self                                             selector:@selector(keyboardWillBeHidden:)                                                 name:UIKeyboardWillHideNotification object:nil];    }

实现方法

-(void)keyboardWillAppear:(NSNotification*)aNotification{    CGSize size = [[[aNotification userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size;    if (size.height == 216) {        [UIView animateWithDuration:0.1 animations:^(void){            CGRect frame = _bottomView.frame;            frame.origin.y = DeviceHeight - 216 -44;            _bottomView.frame = frame;        }];    }else{        [UIView animateWithDuration:0.1 animations:^(void){            CGRect frame = _bottomView.frame;            frame.origin.y = DeviceHeight - 252 -44;            _bottomView.frame = frame;        }];    }}- (void)keyboardWillBeHidden:(NSNotification*)aNotification{    [UIView animateWithDuration:0.1 animations:^(void){        CGRect frame = _bottomView.frame;        frame.origin.y = DeviceHeight -44;        _bottomView.frame = frame;    }];}

其中 DeviceHeight 为设备高度的宏定义，用于 3.5、4寸屏幕的适配。

最后要在dealloc方法中移除通知

-(void)dealloc{    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];}

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