How to invoke a method from UIViewController class to Custom UIView class - ios

Question

I am not able to call the method which is written in UIViewController(aViewController) from my custom view bView .
I want to call the method function on my button(btn) click in UIView(bView). But when I click the button, i am getting the following error.
unrecognized selector sent to instance....
Here is my code:
aViewController.h
#import "bView.h"
#import "cViewController.h"
-(void)function;
aViewController.m
-(void)viewDidLoad{
bView = [[bView alloc]init];
[bView makeView];
bView.bViewController = self;
[self.view addSubView:bView];
}
-(void)function{
cViewController *nextViewController = [[cViewController alloc] initWithNibName: nil bundle: nil];
[self.navigationController pushViewController: nextViewController animated: YES];
}
bView.h
#import "bViewController.h"
#interface bView : UIView{
UIButton btn;
bView *BView;
}
-(void)makeView;
-(void)function;
#property (nonatomic,readonly) UIButton *btn;
#property (assign) UIViewController* aViewController;
bView.m
#import "bView.h"
#import "aViewController.h"
#impementation bView
#synthesize btn;
#synthesize aViewController;
-(void)makeView{
btn= [UIButton buttonWithType:UIButtonTypeRoundedRect];
UIImage *btnimg = [UIImage imageNamed:#"btn.png"];
[btn setBackgroundImage:btnimg forState:UIControlStateNormal];
btn.frame = CGRectMake(65, 380, 60, 60);
[self addSubview:btn];
btn.userInteractionEnabled = YES;
[btn addTarget:aViewController action:#selector(function) forControlEvents:UIControlEventTouchUpInside];
}
How to solve it?

Answer 1

You are setting a target to button in [bView makeView]; method, but at that time bView's aViewController is nil because you are setting it only on the next line. So try this:
-(void)viewDidLoad{
bView = [[bView alloc]init];
bView.bViewController = self;
[bView makeView];
[self.view addSubView:bView];
}

Answer 2

this is how you do it, first off, get rid of the "bView.bViewController = self", it doesn't work that way, you shouldn't do this, ever.
-(void)viewDidLoad {
bView = [[bView alloc]init];
[bView makeView];
[self.view addSubView:bView];
[[bView btn] addTarget:self action:#selector(function) forControlEvents:UIControlEventTouchUpInside];
}
function is declared in your UIViewController, not your UIView, so you must call to the button in your viewdidLoad through the bView and then assign it a target and action. I still wouldn't use this method that you are using, but this will do it.
this is the magic:
[[bView btn] addTarget:self action:#selector(function) forControlEvents:UIControlEventTouchUpInside];
AND, remove these lines from the UIView:
#property (assign) UIViewController* aViewController;
-(void)function;
[btn addTarget:aViewController action:#selector(function) forControlEvents:UIControlEventTouchUpInside];
you should remove these if your intent is for the UIViewController to have the function "-(void)function" and I assume this is what you meant. I'm assuming that your "function" is supposed to be called in your UIViewController
for out purposes here, this:
[[bView btn] addTarget:self action:#selector(function) forControlEvents:UIControlEventTouchUpInside];
is the same thing as this:
[bView.btn addTarget:self action:#selector(function) forControlEvents:UIControlEventTouchUpInside];
and
bView.btn = #property (nonatomic,readonly) UIButton *btn;
In fact, you don't need to call this button in any UIView, given what you are showing, just call this in your viewDidLoad, like this:
-(void)viewDidLoad
{
[super viewDidLoad];
UIButton * btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
UIImage *btnimg = [UIImage imageNamed:#"btn.png"];
[btn setBackgroundImage:btnimg forState:UIControlStateNormal];
btn.frame = CGRectMake(65, 380, 60, 60);
btn.userInteractionEnabled = YES;
[self.view addSubview:btn];
[btn addTarget:self action:#selector(function) forControlEvents:UIControlEventTouchUpInside];
}
I'm showing you this because you aren't setting up the UIView correctly in the first place by invoking super on it's designated initializer so the best bet now is to just place the button in your viewDidLoad and move on, this is the solution until you understand how the initialize a UIView and set it up correctly. There's a lot of stuff that is wrong with the UIView you have set up and tried to subclass and it's going to be easier for you to just make the button in viewDidLoad and then learn how to subclass correctly in the future.