iOS 监听键盘高度，输入框上升

 //设置输入框 ---《因为输入框用了get方法，所以第一次调用输入框要用self 调用》；
     self.textlab.frame=CGRectMake(, , , );
     _textlab.layer.borderColor=[UIColor blueColor].CGColor;
     _textlab.layer.borderWidth= 0.5f;
     _textlab.backgroundColor=[UIColor colorWithRed:0.830 green:0.801 blue:0.881 alpha:1.000];

     //添加输入框到视图
     [self.view addSubview:self.textlab];

     //监听键盘，键盘出现
     [[NSNotificationCenter defaultCenter]addObserver:self 
                                               selector:@selector(keyboardwill:) 
                                                   name:UIKeyboardWillShowNotification object:nil];

     //监听键盘隐藏
     [[NSNotificationCenter defaultCenter]addObserver:self 
                                               selector:@selector(keybaordhide:) 
                                                   name:UIKeyboardWillHideNotification object:nil];

     //设置点击手势，当点击空白处，结束编辑，收回键盘
     UITapGestureRecognizer *tapp=[[UITapGestureRecognizer alloc]
                                     initWithTarget:self action:@selector(tapAction:)];
     //开启交互
     self.view.userInteractionEnabled=YES;
     //添加手势到视图
     [self.view addGestureRecognizer:tapp];

2、里面方法的实现

 //点击手势方法
 -(void)tapAction:(UITapGestureRecognizer *)sender
 {
     [self.view endEditing:YES];
 }

 //当键盘出现时，调用此方法
 -(void)keyboardwill:(NSNotification *)sender
 {
     //获取键盘高度
     NSDictionary *dict=[sender userInfo];
     NSValue *value=[dict objectForKey:UIKeyboardFrameEndUserInfoKey];
     CGRect keyboardrect = [value CGRectValue];
     int height=keyboardrect.size.height;

     //如果输入框的高度低于键盘出现后的高度，视图就上升；
     if ((_textlab.frame.size.height + _textlab.frame.origin.y)>(self.view.frame.size.height - height))
     {
         self.view.frame = CGRectMake(, -height, self.view.frame.size.width, self.view.frame.size.height);
     }
 }

 //当键盘隐藏时候，视图回到原定
 -(void)keybaordhide:(NSNotification *)sender
 {
      self.view.frame = CGRectMake(, , self.view.frame.size.width, self.view.frame.size.height);
 }

 //输入框的get方法
 -(UITextField *)textlab
 {
     if (_textlab==nil)
     {
         _textlab=[UITextField new];
     }
     return _textlab;
 }

 防止键盘遮挡方式二;

调用UITextField 输入框的代理方法 <UITextFieldDelegate>

 //开始编辑输入框的时候，软键盘出现，执行此事件
 -(void)textFieldDidBeginEditing:(UITextField *)textlab
 {
     //获取当前输入框的位置信息
     CGRect frame = textlab.frame;
     //获取键盘底部位置与键盘最高点之间的距离，键盘高度256
     int offset = frame.origin.y + frame.size.height - (self.view.frame.size.height - 256.0);
     //设置视图上升的时间
     NSTimeInterval animaTime = 0.30f;
     //字符串随意也行...
     [UIView beginAnimations:@"ResizeForKeyboard" context:nil];
     //添加视图上的上升时间0.3f
     [UIView setAnimationDuration:animaTime];

     //将视图的Y坐标向上移动offset个单位，以使下面腾出地方用于软键盘的显示
     if(offset > )
         self.view.frame = CGRectMake(0.0f, -offset, self.view.frame.size.width, self.view.frame.size.height);
     //提交动画
     [UIView commitAnimations];
 }

//当用户按下return键或者按回车键，keyboard消失
-(BOOL)textFieldShouldReturn:(UITextField *)textField
{
    //收回键盘第一响应者意思...
    [textField resignFirstResponder];
    return YES;
}

//输入框编辑完成以后，将视图恢复到原始状态
-(void)textFieldDidEndEditing:(UITextField *)textField
{
    self.view.frame =CGRectMake(, , self.view.frame.size.width, self.view.frame.size.height);
}