#pragma mark - reg & unreg notification

- (void)regNotification

{

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillChangeFrame:) name:UIKeyboardWillChangeFrameNotification object:nil];

}

- (void)unregNotification

{

[[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillChangeFrameNotification object:nil];

}

#pragma mark - notification handler

- (void)keyboardWillChangeFrame:(NSNotification *)notification

{

NSDictionary *info = [notification userInfo];

CGFloat duration = [[info objectForKey:UIKeyboardAnimationDurationUserInfoKey] floatValue];

CGRect beginKeyboardRect = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue];

CGRect endKeyboardRect = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];

CGFloat yOffset = endKeyboardRect.origin.y - beginKeyboardRect.origin.y;

CGRect inputFieldRect = self.inputTextField.frame;

CGRect moreBtnRect = self.moreInputTypeBtn.frame;

inputFieldRect.origin.y += yOffset;

moreBtnRect.origin.y += yOffset;

[UIView animateWithDuration:duration animations:^{

self.inputTextField.frame = inputFieldRect;

self.moreInputTypeBtn.frame = moreBtnRect;

}];

}

通过获取键盘消息的开始状态、结束状态，以及变化周期，可以计算出具体的Y偏移，从而在相同时间里做相同偏移量。

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