如果自定义UIView包含> 1个子层，则应用在touches上崩溃开始，为什么？

Question

I have a few custom UIView objects that all handle drawing like this:

- (void)drawRect:(CGRect)rect {
    // ^ I init the layers 1 and 2
    [self.layer insertSublayer:layer1 atIndex:0]; // 1 or more
    [self.layer insertSublayer:layer2 atIndex:1];
}

They also have a - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event; with nothing else inside but a NSLog .

I add them all inside my main ViewController like so:

- (void)viewDidLoad
{
    [super viewDidLoad];

    CustomView *myViewWith1Layer = [[CustomView alloc] initWithFrame:CGRectMake(20, 20, 440, 260)];
    [self.view addSubview:myViewWith1Layer];

    CustomViewLayered *myViewWith2Layer = [[CustomViewLayered alloc] initWithFrame:CGRectMake(40, 260, 200, -120)];
    [self.view addSubview:myViewWith2Layers];
}

When I run my app, if I tap on a view that has only a single layer - I get my NSLog to show, and everything's fine. If, on the other hand, I tap on views with 1+ layers, the app crashes ( objc_msgSend log shows up with "EXC_BAD_ACCES (code=1, address=...") . I guess this is somehow related with ARC , which I have enabled.

How do I add multiple layers to a view, without it being messed up by ARC ?

Answer 1

I don't think that this is an ARC problem, but creating and inserting the layers in drawRect is wrong. This should be done (only once) in the init method of the view, eg in initWithFrame .

Answer 2

In my case, the solution was definitely related to ARC.

When initialising my delegates, I immediately assigned them to the layer.delegate property, and ARC would remove the object from existence immediately after that.

So for each layer, I add a strong @property (strong, nonatomic) delegatesClass *delegatesName and initialise straight to the property. After that, I assign the layer.delegate = self.delegatesName .

This did solve the issue, although I'm not sure if it is the right way to do things.