Set navigation left bar button in objective C

    UIButton *btnBack =  [UIButton buttonWithType:UIButtonTypeCustom];
    [btnBack setImage:[UIImage imageNamed:@"ic_Back"] forState:UIControlStateNormal];
    [btnBack setFrame:CGRectMake(0, 0, 35, 35)];
    btnBack.showsTouchWhenHighlighted = YES;
    [btnBack addTarget:self action:@selector(btnback_Click:)forControlEvents:UIControlEventTouchUpInside];
    UIView *leftBarButtonItems = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 35, 35)];
    [leftBarButtonItems addSubview:btnBack];
    self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:leftBarButtonItems];