Question

Could you help me with this error.
I’ve tried this code, with ARC and non ARC.
with ARC is OK. but with non ARC.
How could I do. help me please. ^__^;

When I push the button, the error occures.
**

#import <UIKit/UIKit.h>
@interface FirstViewController : UIViewController {

    void                    (^_myOne)(void);    
    UIView*                 _viewOne;
}
@property (nonatomic, retain)   void            (^myOne)(void);
@property (nonatomic, retain)   UIView*         viewOne;
- (void)useFirstOne:(void(^)(void))blockOne;
@end
#import "FirstViewController.h"
@implementation FirstViewController
@synthesize myOne = _myOne, viewOne = _viewOne;
- (void)useFirstOne:(void (^)(void))blockOne {

    blockOne ();
}
- (void)buttonPressed {
        [self useFirstOne:self.myOne]; //If I put this line into 'viewDidLoad', has no problem.
}
- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor redColor];
    UIButton* buttonA = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    buttonA.frame = CGRectMake(0, 0, 100, 44);
    buttonA.center = CGPointMake(160, 350);
    [buttonA setTitle:@"Button" forState:UIControlStateNormal];
    [buttonA addTarget:self action:@selector(buttonPressed) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:buttonA];
    _viewOne = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 100, 100)];
    [self.view addSubview:self.viewOne];

    _myOne = ^{
        self.viewOne.backgroundColor = [UIColor grayColor];
    };
}
@end

**

Answer 1

This:

_myOne = ^{
    self.viewOne.backgroundColor = [UIColor grayColor];
};

needs to be this:

_myOne = Block_copy(^{
    self.viewOne.backgroundColor = [UIColor grayColor];
});

This is because block objects are stack allocated, which means that they are deallocated when they go out of scope. So when the viewDidLoad method finishes executing, the block held in _myOne will be deallocated, and if you try to use it it will crash. When you copy a block, the copy is heap allocated and will survive until it is released.