Is it possible to add custom tools to a PKToolPicker?

3 min read 05-10-2024

Is it possible to add custom tools to a PKToolPicker?

Can You Customize the PKToolPicker in Swift? Unlocking Powerful Tool Options for Your Apps

Introduction

The PKToolPicker is a powerful iOS framework component allowing you to provide users with a convenient way to manipulate and interact with PDF documents. However, the default set of tools might not always meet the specific requirements of your application. So, the question arises: Can you add custom tools to the PKToolPicker?

The Short Answer: Not Directly

Unfortunately, Apple's framework doesn't provide a direct mechanism to add custom tools to the PKToolPicker. The available tools are predefined and limited to the basic functions like drawing, adding text, and highlighting.

Let's look at a basic example:

import UIKit
import PDFKit

class ViewController: UIViewController {

    @IBOutlet weak var pdfView: PDFView!
    var toolPicker: PKToolPicker!

    override func viewDidLoad() {
        super.viewDidLoad()

        // Load a PDF file
        if let url = Bundle.main.url(forResource: "MyPDF", withExtension: "pdf") {
            pdfView.document = PDFDocument(url: url)
        }

        // Create a tool picker
        toolPicker = PKToolPicker()

        // Set the tool picker's visible tools (only the default ones)
        toolPicker.setVisibleTools([.select, .annotate, .draw, .addText, .eraser])

        // Set the delegate for handling tool changes
        toolPicker.delegate = self

        // Display the tool picker
        pdfView.toolPicker = toolPicker
    }

    // MARK: - PKToolPickerDelegate methods
    func toolPicker(_ toolPicker: PKToolPicker, didSelect tool: PKTool) {
        // Handle tool selection, e.g., update UI
        print("Tool selected: \(tool)")
    }
}

This code demonstrates how to use the PKToolPicker with its default tools. However, the code lacks the flexibility to include your custom functionalities.

Workarounds and Solutions

While you can't directly add custom tools to the PKToolPicker, you can leverage the existing framework and implement alternative solutions:

Subclassing and Overriding: You can subclass the PKToolPicker and override the setVisibleTools method to hide the default tools and introduce your custom tools. This approach allows for a greater degree of control over the tool picker's appearance, but it might not be directly compatible with all future framework updates.
Custom Toolbar: You can create your own custom toolbar and integrate it with your PDFView. This approach offers maximum flexibility. You can design a toolbar with custom buttons and actions that mimic or even exceed the functionality of the PKToolPicker.
Third-Party Libraries: Several third-party libraries extend the functionality of the PDFKit framework, providing more customization options and tools. These libraries often offer ways to create custom toolbars and add specific functionalities.

Choosing the Right Approach

The best approach depends on your specific needs and project complexity. If you need a simple solution with limited customization, the PKToolPicker with its default tools might be sufficient. For more extensive control and unique functionalities, consider the workaround solutions.

Example: Custom Toolbar with Signature Tool

Imagine you need to add a signature tool to your PDF application. You can implement this by creating a custom toolbar with a dedicated button for signing.

1. Design a custom toolbar:

Create a UIView subclass for your custom toolbar.
Add buttons for your desired tools (e.g., "Signature").
Implement actions for each button.

2. Implement the signature tool:

Create a UIView subclass to represent the signature canvas.
Use touch events to capture the user's signature strokes.
Save the signature data (e.g., as an image).

3. Integrate the custom toolbar with your PDFView:

Display the custom toolbar when you want to enable editing.
Handle the signature button action:
- Show the signature canvas.
- Capture the user's signature.
- Draw the signature on the PDF using PDFAnnotation.

Conclusion

While the PKToolPicker doesn't directly support custom tools, you can leverage the existing framework and implement creative workarounds to achieve your desired functionality. Consider the level of customization you need and choose the approach that best suits your project. By exploring these alternative solutions, you can unlock a wider range of possibilities and build powerful PDF editing experiences within your iOS applications.