iOS键盘弹出 视图向上滚动键盘高度

2017-04-11  本文已影响1738人  打瞌睡de小男孩

1.先添加对键盘的监听

[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
 [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];

当系统消息出现UIKeyboardWillShowNotification和UIKeyboardWillHideNotification消息就会调用我们的keyboardWillShow和keyboardWillHide方法。

2.实现监听方法

#pragma mark ---- 根据键盘高度将当前视图向上滚动同样高度
///键盘显示事件
- (void)keyboardWillShow:(NSNotification *)notification {
    //获取键盘高度,在不同设备上,以及中英文下是不同的
    CGFloat kbHeight = [[notification.userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size.height;
    
    //计算出键盘顶端到inputTextView panel底端的距离(加上自定义的缓冲距离INTERVAL_KEYBOARD)
    CGFloat offset = kbHeight;
    
    // 取得键盘的动画时间,这样可以在视图上移的时候更连贯
    double duration = [[notification.userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];
    
    //将视图上移计算好的偏移
    if(offset > 0) {
        [UIView animateWithDuration:duration animations:^{
            self.view.frame = CGRectMake(0.0f, -offset, self.view.frame.size.width, self.view.frame.size.height);
        }];
    }
}
#pragma mark ---- 当键盘消失后,视图需要恢复原状
///键盘消失事件
- (void)keyboardWillHide:(NSNotification *)notify {
    // 键盘动画时间
    double duration = [[notify.userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];
    //视图下沉恢复原状
    [UIView animateWithDuration:duration animations:^{
        self.view.frame = CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height);
    }];
}

3.注销通知

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

4.然后在这里安利一个很好的第三方 IQKeyboardManager 特别好用
有需要的可以直接去下载 https://github.com/hackiftekhar/IQKeyboardManager

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