title: How to disable the android back button in certain screen
body: <p>I would like to disable the android back button only in some pages. I used the following code:</p>
  
  <pre><code>  componentWillUnmount(){
        //For disabling the back button on cellphone
        BackHandler.removeEventListener('hardwareBackPress', this.handleBackButton);
      }
      componentWillMount() {
           ParkToolbar.init( this );
      }
  
      //For disabling the back button on cellphone
      handleBackButton() {
          ToastAndroid.show('you cannot return', ToastAndroid.SHORT);
          return true;
      }
  
      componentDidMount() {
          toolbarActiveItem = this.state.user; 
          ParkToolbar.setActiveItem(this.props.navigation.state.params.activeSection);
  
          //For disabling the back button on cellphone
          BackHandler.addEventListener('hardwareBackPress', this.handleBackButton);
      }
  </code></pre>
  
  <p>The problem is that, when I use the code in one page(Screen) in my program, the back button will disable in all pages(Screen) in every part of my application. Do you have any idea how to manage it in such a way that it only disable the back button for a single page(screen)?</p>
  
  <p><strong>UPDATE:</strong> 
  I have also tested the code with BackAndroid and the same problem occurred. </p>