在通知中心建立一个广播来监听键盘的弹出和弹回,在监听事件中加入触发事件的一些操作。
[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(keyboardWillChange:) name:UIKeyboardWillChangeFrameNotification object:nil];[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(keyboardwillhide:) name:UIKeyboardWillHideNotification object:nil];
监听键盘的一些通知:
// 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
在这里我需要实现的效果(如下图)是在在键盘弹出时,使下方的toolbar向上移动到相应位置,因此需要知道键盘的高度和弹出动画的时间,通过广播监听来得到键盘的frame和弹出动画时间:
NSString *duration = userInfo[UIKeyboardAnimationDurationUserInfoKey];CGRect keyboardFrame = [userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];
再通过动画效果,改变tableview和toolbar的frame,使得键盘在弹出时不会被遮挡:
[UIView animateWithDuration:[duration doubleValue] delay:0.0 options:UIViewAnimationOptionCurveLinear animations:^{_tableview.frame = CGRectMake(0, 64 , SIZE.width, SIZE.height - 64 - keyboardFrame.size.height - 50);footView.frame = CGRectMake(0, SIZE.height - keyboardFrame.size.height - 50, SIZE.width, 50);} completion:^(BOOL finished) {NSIndexPath *path = [NSIndexPath indexPathForRow:_dataArray.count - 1 inSection:0];[_tableview scrollToRowAtIndexPath:path atScrollPosition:UITableViewScrollPositionBottom animated:YES];}];
效果图: