Understanding the Issue with PPRevealSideViewController and Modal View Controllers

In this article, we will delve into the world of iOS development and explore a common issue that developers often encounter when working with modal view controllers. Specifically, we will examine why a view might appear blank after dismissing a PPRevealSideViewController instance.

Introduction to PPRevealSideViewController

PPRevealSideViewController is a popular side-viewing controller for iOS, used to create a slide-out menu or drawer in an app. It provides a convenient and easy-to-use API for managing the presentation and dismissal of modal view controllers. However, like any complex piece of code, it can sometimes exhibit unexpected behavior.

The Problem: Blank View after Dismissing ModalViewController

In this section, we’ll outline the problem described by the OP in their Stack Overflow post:

When a user taps on a cell in a side view to show a modal PPRevealSideViewController instance, and then dismisses it, the original view appears blank. However, if the user moves the side view slightly before looking at the screen again, the original view is displayed correctly.

Potential Causes of the Issue

At first glance, this issue seems puzzling, as the problem only manifests when using PPRevealSideViewController and dismissing a modal view controller. There might be multiple factors contributing to this behavior:

• Preloading the View: The OP mentions that preloading the view on viewWillAppear or didAppear could be the culprit.
• Layout Issues: There might be an issue with the layout of the side view or its contents, causing the blank space.
• Controller Hierarchy: The relationship between the modal view controller and the original view could be at fault.

Understanding Preloading

Preloading is a technique where you load a view into memory before it’s actually displayed on screen. In iOS, views are loaded incrementally as they’re needed, which can lead to performance issues if not managed correctly.

In this case, the OP suspected that preloading was causing the blank space:

“This was a side effect of your preload call on viewWillAppear or DidAppear in fact.”

To address this issue, we need to understand how to manage view loading and unloading properly.

Managing View Loading and Unloading

When creating a modal view controller with PPRevealSideViewController, you can use the preload property to control whether the view is loaded immediately:

{< highlight vue -->
import PPRevealSideViewController from 'PPRevealSideViewController'

// ...

const revealController = PPRevealSideViewController.createViewController()
revealController.preload = false // Unload the view when dismissed
// ...
</highlight> }

In this case, setting preload to false ensures that the view is not loaded until it’s actually needed.

Adding a Check in the Controller

Another approach is to add a check in the controller to see if the view needs to be reloaded after dismissing the modal:

{< highlight vue -->
import PPRevealSideViewController from 'PPRevealSideViewController'

class SideViewController extends UIViewController {
  @Prop {type: Boolean} preload

  override viewDidLoad() {
    super.viewDidLoad()
    // ...
  }

  override func viewWillLayoutSubviews() {
    if (self.preload && !self.sideViewController) {
      // Reload the view
      self.view.reload()
    }
  }

  // ...

  sideViewController: PPRevealSideViewController?

  // ...
}
</highlight> }

In this example, the viewWillLayoutSubviews method checks whether the view should be reloaded based on the value of the preload property and the current state of the modal controller.

Conclusion

The blank space issue after dismissing a PPRevealSideViewController instance can often be attributed to improper preloading or layout issues. By understanding how to manage view loading and unloading, as well as adding checks in the controller, you can resolve this common problem and provide a smoother user experience for your app.

Additional Considerations

When working with modal view controllers, it’s essential to consider other factors that might impact the behavior of your app:

• State Management: How do you manage state between view controllers? This can affect the performance and stability of your app.
• Layout and Positioning: How do you position and layout views in your app? Properly managing this aspect is crucial for a smooth user experience.

In the next section, we’ll explore some best practices for managing state between view controllers and optimizing layout and positioning.

Last modified on 2024-09-08