Question

I have a UIViewController Class which holds 2 custom UIView classes which are:

ItemView

DrawingView

in UIViewController ViewDidLoad method I have the following code:

- (void)viewDidLoad
{

    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
    item = [[ItemView alloc] initWithFrame:CGRectMake(self.view.frame.size.width/2, self.view.frame.size.height/2, 230, 230)];
    item.opaque = NO;

    [self.view addSubview:item];

    drawing = [[DrawingView alloc] initWithFrame:self.view.frame];
    [self.view insertSubview:drawing aboveSubview:item];
    [item release];
    [drawing release];

}

The DrawingView class gets UITouches and accordingly draw on the screen.

My question is:

I can draw all over the screen except for on top of ItemView class object. DrawingView class cannot draw on to ItemView.

Let me explain it in another word:

The DrawView class works on the screen except for the area of itemView subview. On top of itemView, DrawView cannot make any draws but other than itemView area, it makes drawing.

What can I do?
What can be the problem?
How can I make drawing on all screen including the itemView area added by addSubview on ViewController class?

EDIT: I am adding a screenshot in order to explain the problem better

EDIT 2: I found that the problem is related to opacity. In the ItemView class, I changed the added UIImageView object alpha value to 0.5f.
The result is semi-transparent view and now my finger drawing is visible. However, this is not what I want. I want to draw on top of the view. I do not want to play with the alpha value.

Answer 1

Finally, I found the answer myself. It is not exactly what I wanted but my solution is based on CALayer.

Instead of using a custom UIView class like ItemView I added the following class method in ItemView Class:

+(CALayer *)imgLayer
{
    UIImage *img = [UIImage imageNamed:@"face.png"];
    CALayer *layer = [CALayer layer];
    CGFloat nativeWidth = CGImageGetWidth(img.CGImage);
    CGFloat nativeHeight = CGImageGetHeight(img.CGImage);
    CGRect startFrame = CGRectMake(0, 0, nativeWidth, nativeHeight);
    layer.contents = (id)img.CGImage;
    layer.frame = startFrame;
    return layer;

}

In My UIVIewController Class I called my static function as following:

    CAGradientLayer *bgLayer =  [GradientView greyGradient];
    bgLayer.frame = self.view.bounds;
    [self.view.layer insertSublayer:bgLayer atIndex:0];

    CALayer *imgLayer =[ItemView imgLayer];
    imgLayer.frame = self.view.bounds;
    [self.view.layer insertSublayer:imgLayer above:bgLayer];

And it works! now I can make drawings on my image.