键盘遮掩控件(textfield/textview.)

    // 解决键盘遮挡问题
//选择didShow是因为需要键盘的高度
//选择willHide是因为视图frame重置需要优先于键盘消失，否则表现得不连贯
      [[NSNotificationCenter defaultCenter] addObserver:self                                               selector:@selector(keyboardWasShown:)                                                   name:UIKeyboardDidShowNotification                                                 object:nil];        [[NSNotificationCenter defaultCenter] addObserver:self                                             selector:@selector(keyboardWasHide:)                                                 name:UIKeyboardWillHideNotification                                               object:nil];

-(void)keyboardWasShown:(NSNotification*)notification{    //获取键盘高度    NSValue* value=notification.userInfo[UIKeyboardFrameBeginUserInfoKey];    CGFloat keyBoradHeight=[value CGRectValue].size.height;    NSNumber* animationTime=notification.userInfo[UIKeyboardAnimationDurationUserInfoKey];    double time=[animationTime doubleValue];    //获取被遮挡控件距离controller底部的距离    float a=self.view4.frame.origin.y+self.view4.frame.size.height;    float b = self.view.frame.size.height-a;    if (b<keyBoradHeight)    {        //动画效果        [UIView animateWithDuration:time                         animations:^         {             //键盘被挡住了             CGRect viewCGrect=self.view.frame;             //视图应该上移所以是－             viewCGrect.origin.y=viewCGrect.origin.y-(keyBoradHeight-b);             [self.view setFrame:viewCGrect];         } completion:nil];    }}-(void)keyboardWasHide:(NSNotification*)notification{    NSValue* value=notification.userInfo[UIKeyboardFrameBeginUserInfoKey];    CGFloat keyBoradHeight=[value CGRectValue].size.height;    float a=self.view4.frame.origin.y+self.view4.frame.size.height;    float b = self.view.frame.size.height-a;             CGRect viewCGrect=self.view.frame;         viewCGrect.origin.y=viewCGrect.origin.y+(keyBoradHeight-b);         [self.view setFrame:viewCGrect];}

-(void)viewWillDisappear:(BOOL)animated{    [super viewWillDisappear:animated];    [[NSNotificationCenter defaultCenter] removeObserver:self                                                    name:UIKeyboardWillHideNotification                                                  object:nil];    [[NSNotificationCenter defaultCenter] removeObserver:self                                                    name:UIKeyboardDidShowNotification                                                  object:nil];}