新增遮罩層的原理是在一個可以操作的UIView下面有另一個UIView,下邊的UIView的作用是遮擋住頁面，使其無法進行操作，直到前一個介面的操作結束，然後直接將後一個UIView移除，程式碼如下：
[UIView animateWithDuration:0.4 animations:^{

    int iconWidth=delegate.currentWidth/2;
    UIView *view=[[UIView alloc]initWithFrame:CGRectMake(iconWidth-60,140,150,105 )];
    [view setBackgroundColor:[UIColor colorWithRed:255.f/255.f green:255.f/255.f blue:255.f/255.f alpha:1]];
    view.layer.cornerRadius=10;
    view.backgroundColor = [UIColor colorWithRed:255. green:55. blue:255. alpha:0.89f];
    view.layer.borderColor = [[UIColor lightGrayColor] CGColor];
    view.layer.borderWidth = 2.0f;
    //view.layer.cornerRadius = 10.0f;
    view.clipsToBounds = YES;

    view1 = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    //view1.backgroundColor = [UIColor colorWithRed:.255 green:.255 blue:.0 alpha:.255];
    [view1 setBackgroundColor:[UIColor whiteColor]];
    [view1 setAlpha:0.2];
 

[UIView animateWithDuration:.8 animations:^{
[self->addRenTV addSubview:view1];//addRenTV是主介面
}];
[view1 addSubview:view];
self->addRenTV.scrollEnabled = NO;
}];
* 其中，view1是下邊的，所以移除時要移除view1，這也是為什麼要把它定義成全域性變數，如果在其他函式裡實現移除就可以直接寫：
[view1 removeFromSuperview];