Cocoa Touch: Creating and Adding Custom View

Question

I create a custom view in cocoa touch that is superclassed by UIView and in my main controller I initialize it and then add it as a subview to the main view, but when I add it to the main view it calls my initializer method again and causes an infinite loop. Am I going about creating my custom view wrong? Here is the mainView

- (void)loadView {
    UIImage* tempImage = [UIImage imageNamed: @"image1.jpg"];
    CustomImageContainer *testImage = [[CustomImageContainer alloc] initWithImage: tempImage andLabel: @"test image" onTop: true atX: 10 atY: 10];
    [self.view addSubview: testImage];
}

and the CustomImageContainer

-(CustomImageContainer *) initWithImage: (UIImage *)imageToAdd andLabel: (NSString *)text onTop: (BOOL) top atX: (int) x_cord atY: (int) y_cord{
    UIImageView *imageview_to_add = [[UIImageView alloc] initWithImage: imageToAdd];
    imageview_to_add.frame = CGRectMake(0, 0, imageToAdd.size.width, imageToAdd.size.height);
    UILabel *label_to_add = [[UILabel alloc] init];
    label_to_add.text = text;
    label_to_add.alpha = 50;
    label_to_add.backgroundColor = [UIColor blackColor];
    label_to_add.textColor = [UIColor whiteColor];
    [self addSubview: imageview_to_add];
    self.frame = CGRectMake(x_cord, y_cord, imageToAdd.size.width, imageToAdd.size.height);
    if (top) {
        label_to_add.frame = CGRectMake(0, 0, imageview_to_add.frame.size.width, imageview_to_add.frame.size.height);
        //[self addSubview: label_to_add];
    }
    else {
        label_to_add.frame = CGRectMake(0,.2 * imageview_to_add.frame.size.height, imageview_to_add.frame.size.width, imageview_to_add.frame.size.height);
    }
    [self addSubview: label_to_add];
    [super  init];
    return self;
}

Answer 1

Why did you put the [super init] statement at the end of the initializer ? When subclassing, you usually put this statement at the start of method.

For UIView subclasses, the designated initializer when creating views in code is initWithFrame:, so you should call it before adding the label and the image. You can use the image to compute the frame needed by the custom view.

-(CustomImageContainer *) initWithImage: (UIImage *)imageToAdd andLabel: (NSString *)text onTop: (BOOL) top atX: (int) x_cord atY: (int) y_cord{
    // The view will gets its frame to the size of the image
    UIImageView *imageview_to_add = [[UIImageView alloc] initWithImage: imageToAdd];

    // Call the designated initializer
    CGRect frame = CGRectMake(x_cord, y_cord, imageToAdd.size.width, imageToAdd.size.height);
    self = [super initWithFrame:frame];

    [self addSubview: imageview_to_add];

    UILabel *label_to_add = [[UILabel alloc] init];
    label_to_add.text = text;
    label_to_add.alpha = 50;
    label_to_add.backgroundColor = [UIColor blackColor];
    label_to_add.textColor = [UIColor whiteColor];

    if (top) {
        label_to_add.frame = CGRectMake(0, 0, imageview_to_add.frame.size.width, imageview_to_add.frame.size.height);
    }
    else {
        label_to_add.frame = CGRectMake(0,.2 * imageview_to_add.frame.size.height, imageview_to_add.frame.size.width, imageview_to_add.frame.size.height);
    }
    [self addSubview: label_to_add];

    return self;
}

If you still have an infinite loop, pause the debugger and search for the recurrent method pattern in the stack trace. This pattern will gives you where the code enters the infinite loop.