ios - Why do both init functions get called

Question

If I have a class that is setup like this to customize a UIView.

@interface myView : UIView

- (id)init {
    self = [super init];
    if(self){
        [self foo];
    }
    return self;
}

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code
        [self foo];
    }
    return self;
}


-(void) foo{
   //Build UIView here 
}

How come foo is called twice whether I use

myView *aView = [[myView alloc]init]]; 

or

myView *aView = [[myView alloc]initWithFram:aFrame]; 

Answer 1

UIView init来电UIView initWithFrame:。由于您覆盖了两者，因此调用您的init方法会导致您的initWithFrame:方法被调用：

换句话说：你的init电话UIView init。UIView init来电initWithFrame:。由于您覆盖initWithFrame:，您的initWithFrame:被调用，而后者又调用UIView initWithFrame:.

由于initWithFrame:总是会调用您的解决方案，因此解决方案是foo从您的init方法中删除对的调用。