都在注释里

//增加监听，当键盘出现或改变时收出消息
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
    
    //增加监听，当键退出时收出消息
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];

- (void)keyboardWillShow:(NSNotification *)aNotification{
    
    NSDictionary *userInfo = [aNotification userInfo];
    NSValue *aValue = [userInfo objectForKey:UIKeyboardFrameEndUserInfoKey];
    CGRect keyboardRect = [aValue CGRectValue];
    int height = keyboardRect.size.height;
    
    // 设置动画的名字
    [UIView beginAnimations:@"Animation" context:nil];
    // 设置动画的间隔时间
    [UIView setAnimationDuration:0.20];
    // 使用当前正在运行的状态开始下一段动画
    [UIView setAnimationBeginsFromCurrentState: YES];
    // 获取到textfiled 距底部距离
    int textToTop = self.view.frame.size.height - self.numberTextFiled.frame.origin.y - self.numberTextFiled.frame.size.height;
    
    if (textToTop > height) {
        // 如果键盘高度小于textfiled距底部的距离 则不需要任何操作
    }else{
        // 当textToTop 小于 height 时
        // 获取到键盘高度和控件底部距离的差值
        int scrolldistance = height - textToTop;
        // 移动视图y 差值距离
        self.view.frame = CGRectMake(self.view.frame.origin.x, self.view.frame.origin.y - scrolldistance, self.view.frame.size.width, self.view.frame.size.height);
    }
    //设置动画结束
    
    [UIView commitAnimations];
    
    
}

//当键退出时调用
- (void)keyboardWillHide:(NSNotification *)aNotification{
    // 设置动画的名字
    [UIView beginAnimations:@"Animation" context:nil];
    // 设置动画的间隔时间
    [UIView setAnimationDuration:0.20];
    // 使用当前正在运行的状态开始下一段动画
    [UIView setAnimationBeginsFromCurrentState: YES];
    // 设置视图移动的位移至原来的y值
    self.view.frame = CGRectMake(self.view.frame.origin.x, 0, self.view.frame.size.width, self.view.frame.size.height);
    //设置动画结束
    [UIView commitAnimations];
    
}