Question

Okay, I’m new to programming in XCode and Objective-C, and have a question.

I can add a UIImageView normally using the drag and drop features in the Storyboard Builder thing. Then I can access it in code by creating a connection to the relavent ViewController, with a control drag and drop and then I can create a outlet. It is then declared in the *.h file with the @property line and synthesized in the *.m file.

BUT, what if I have a more complex view and it would take far too long drop and drag everything onto the screen and what if I wanted to change the position of the objects during execution?

I have tried using this in the ViewDidLoad Method:

NSMutableArray *mutableArray = [NSMutableArray array];
UIImage * pic = [UIImage imageNamed: @"Blue.png"];
for (int x = 0;x<10;x++){
    for (int y =0;y<10;y++){
        UIImageView *imageView = [[UIImageView alloc] initWithImage:pic];
    imageView.frame =CGRectMake(x*23,y*41,32,41);
[mutableArray addObject:imageView];
    }
}

This, I hoped would make a grid of UIImageViews and hold them in a NSMutableArray, but nothing appears on screen. How do you do a similar process to the drag and drop but in code? I realize I’m not synthesizing anything, and I only declare one instance UIImageView, but I thought If I put the declaration in the for loops then it would complain because it would be creating multiple variables with the same name. Is there anyway to create a load of UIImageViews in a few lines of code using a loop? I though of maybe just editing the sting used as the identifier for the pointer variable e.g. “image1”, “image2″….. But I didn’t know how to use a string type variable as the name of an identifier.

P.S. – I googled the CGRectMake procedure and the parameters are (x-coordinates,y-coordinates,width,height).

Any help would be greatly appreciated :).

Answer 1

You need to add them to the subview.

[self.view addSubview:imageView];

Instead of adding them to an array you could use tags to identify the individual UIImageView, it all depends on what you prefer.

UIImage * pic = [UIImage imageNamed: @"Blue.png"];
int tagInt=1;
for (int x = 0;x<10;x++){
    for (int y =0;y<10;y++){
        UIImageView *imageView = [[UIImageView alloc] initWithImage:pic];
        imageView.frame =CGRectMake(x*23,y*41,32,41);
        imageView.tag=tagInt;
        [self.view addSubview:imageView];
        tagInt++;
    }
}

Then to access the individual UIImageView

UIImageView *imageView = (UIImageView*)[self.view viewWithTag:1];