Subclassing UIView or composing with UIView

Question

I'll start by saying what I want to do because I'm unsure if I'm asking the right question. I'm making a grid based map and am going to hold an array of objects to keep the state and presentation of the map. Each object will be of a Tile class. Should I be subclassing UIView or sublass NSObject and have an ivar of UIView. I was also planning to have a UIImageView inside the UIView to load the image that represents that bit of the map. Lastly, I wanted to load the view from a NIB.

Individually I know how to do each of these things but unsure of the best practice. Any thoughts?

Answer 1

Have you considered Core Animation layers? You can create a single view with a grid of layers each with their own bounds and position within the view. It sounds like it might give you what you need. On the phone, setting a layer's contents with an image is as simple as this:

CALayer *gridLayer = [CALayer layer];
[gridLayer setContents:(id)[gridImage CGImage]];
[gridLayer setBounds:[gridImage bounds]];

// Position the layer's center a x:25.0 y:25.0 within the view
[gridLayer setPosition:CGPointMake(25.0f, 25.0f)];

[[view layer] addSublayer:gridLayer];

The variable gridImage is a UIImage* you've allocated somewhere. You would just need to calculate your layer rects and positions and place them accordingly.

Answer 2

Make sure you have a clear definition of which particular classes/objects comprise your model, your controller and your view. Your data and data logic should be in the model, your display in the view and you should tie them together with the controller.

The simplest way to accomplish a grid is to use UIImageViews that are positioned by a single controller. The model will track the logical relationships between the map squares and relay that to the controller which will load the images into the UIIMageView. The controller will handle loading everything from nib.

However, using CALayers is the preferred cutting edge method. The basic model,controller, view relationship is the same except that the CALayers replace the ImageViews.

Answer 3

If I uderstand right, you can make subclass of UIImageView.