title: Adding custom back button on navigation bar
body: <p>I am trying to add custom back button on navigation bar but it is not working below is my code </p>
  
  <pre><code>-(void)addLeftButton
  {
      UIImage *buttonImage = [UIImage imageNamed:@"btn_back.png"];
  
      UIButton *aButton = [UIButton buttonWithType:UIButtonTypeCustom];
  
      [aButton setBackgroundImage:buttonImage forState:UIControlStateNormal];
  
      aButton.frame = CGRectMake(0.0, 0.0, buttonImage.size.width,   buttonImage.size.height);
  
      UIBarButtonItem *aBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:aButton];
  
     [aButton addTarget:self action:nil forControlEvents:UIControlEventTouchUpInside];
  
     self.navigationItem.backBarButtonItem = aBarButtonItem;
  }  
  </code></pre>
  
  <p>Please tell what's wrong with this code</p>