预期标识符

Question

Please can anyone tell me why this piece of code isn't working? I've got a dictionary which contains UIViews with tables inside associated with the keys which are the names of the corresponding buttons (there are a lot of them). So what I actually want to do is to change the view visibility on the corresponding button click. But the issue is that the expression to do that is not accepted by Xcode and I get the Expected Identifier error.

- (IBAction)choosingButtonClicked:(id)sender {
    if ([sender currentTitle]) {
        [(UIView *)[self.selectionTables objectForKey:[sender currentTitle]]].hidden = ![(UIView *)[self.selectionTables objectForKey:[sender currentTitle]]].isHidden;
    }
}

Answer 1

First of all, with all due respect, I agree with trojanfoe comments. Its not working because its not properly written.

Now, lets try to streamline it with below code:

- (IBAction)choosingButtonClicked:(id)sender {
    NSString *title = [sender currentTitle];

    if (title) {
        UIView *selectionView = (UIView *)self.selectionTables[title];
        selectionView.hidden = !selectionView.isHidden;
    }
}

Answer 2

Your code is too complex, because of that even the author can't understand it. If we re-write your code using local variables, it will look like:

- (IBAction)choosingButtonClicked:(id)sender
{
    NSString *title = [sender currentTitle];
    if (title)
    {
        UIView *tempView  = (UIView *)[self.selectionTables objectForKey:title];
        [tempView].hidden = ![tempView].isHidden;
    }
}

If you check the code now, you can see that the following code is causing the issues:

[tempView].hidden = ![tempView].isHidden;

Change your method like:

- (IBAction)choosingButtonClicked:(id)sender
{
    NSString *title = [sender currentTitle];
    if (title)
    {
        UIView *tempView = (UIView *)[self.selectionTables objectForKey:title];
        tempView.hidden  = !(tempView.isHidden);
    }
}