iOS need help to insert a button to UIView.

- (GMGridViewCell *)GMGridView: (GMGridView *)gridView cellForItemAtIndex: (NSInteger)index
{  
    CGSize size = [self sizeForItemsInGMGridView:gridView];
    
    GMGridViewCell *cell = [gridView dequeueReusableCell];
    
    if (!cell) 
    {
        cell = [[GMGridViewCell alloc] init];
        // create an UIView
        UIView      *view       =   [[UIView alloc] initWithFrame:CGRectMake(0, 0, size.width, size.height)];
 
        // do some customization for my view
        view.backgroundColor = [UIColor purpleColor];
        view.layer.masksToBounds = NO;
        view.layer.cornerRadius = 8;
        view.layer.shadowColor = [UIColor grayColor].CGColor;
        view.layer.shadowOffset = CGSizeMake(5, 5);
        view.layer.shadowPath = [UIBezierPath bezierPathWithRect:view.bounds].CGPath;
        view.layer.shadowRadius = 8;

        // create a button called checkBox
        UIButton    *checkBox   =   [[UIButton alloc] initWithFrame:CGRectMake(70, 20, 150, 25)];
        [checkBox   setTitleColor:[UIColor purpleColor] forState:UIControlStateNormal];
        [checkBox   setImage:[UIImage imageNamed:@"checkbox_not_ticked"] forState: (UIControlStateNormal)];
            // add checkbox to my view
[B]        [view addSubView: checkBox]  [/B]
        cell.contentView = view;

    }

[view addSubview:checkBox];

[[cell.contentView subviews] makeObjectsPerformSelector:@selector(removeFromSuperview)];