iOS 防止输入时键盘覆盖掉输入框

添加监听者

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

监听键盘之后的操作 可以根据自己的需要调整高度的大小

- (void)keyboardwasChange:(NSNotification *)info {
    CGRect keyFrame = [info.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];

    CGFloat tY = keyFrame.origin.y - self.view.frame.size.height - 64;

    self.view.transform = CGAffineTransformMakeTranslation(0, tY);
}