Add References and Set a License - iOS Swift

This tutorial shows how to create a project, add references, and set the license in a Swift iOS application using the LEADTOOLS SDK.

Summary This tutorial covers how to set a license in a Swift iOS application.
Completion Time 20 minutes
Project Download tutorial project (10 KB)
Platform Swift iOS Application
IDE Xcode
Runtime License Download LEADTOOLS
Try it in another language

Required Knowledge

Before any functionality from the SDK can be leveraged, a valid runtime license will have to be set.

For instructions on how to obtain a runtime license refer to Obtaining a License.

Create the Project

Launch Xcode and select Create a new Xcode project.

Screenshot of Xcode launch screen.

Select iOS at the top and App under the Application section, then click Next.

Screenshot of template selection.

Fill in the following and click Next:


The Organization Identifier and Product Name combine to make the Bundle Identifier which must be unique.

Screenshot of options screen.

Finally, select the location to create the new project and click Create. After you create a new project, the .xcodeproj file will open. It can also be accessed by double-clicking on the bundle file to the left in the Project Navigator.

Screenshot of project save location.

Add the LEADTOOLS Framework Packages

To leverage the LEADTOOLS SDK in a Swift iOS project, references to the LEADTOOLS Framework files will be needed.

Framework files can be added by one of the following two methods:

The LEADTOOLS Frameworks can be found here: <INSTALL_DIR>/LEADTOOLS22/Bin/Xcode/XCFrameworks/iOS

Once a framework file is added, a new folder called Frameworks will be added to the Project Navigator, containing the added framework files.

Screenshot of the Frameworks and Libraries section.

To allow Xcode to utilize these Framework files, a few more steps are required.

If done correctly the entry should look something like this:

Next, find the entry called Objective-C Bridging Header, under the Swift Compiler - General section. Also, double-click to the right of it and type in the following and hit entry:

Switch Validate Workspace under the Build Options section near the top to Yes. This is needed to bypass a build error when using the simulator.

Validate Workspace Setting.

Right-click on the blue file in the Project Manager and select New File.... In the new window select Header File from the iOS and Source sections and click Next. At the top change the Save As: name to Leadtools-Bridging-Header.h, this is the same name as the one you provided in the Objective-C Bridging Header entry above and it MUST match. Then click the check box under the Targets section below and click Create.

SCreenshot of adding the Header File.

The new .h file will be displayed upon creation. Between the #define and #endif section, list the framework .h files containing the API needed for the project.

In this tutorial we only need the main leadtools.h file so list it as follows:

#import <Leadtools/Leadtools.h> 


All framework imports will follow the same structure. For example, leadtools.codecs it would be #import <Leadtools.Codecs/Leadtools.Codecs.h>.

Screenshot of the imports.

Once finished click Project -> Build, or Command B, to build the project. If done correctly everything should build without error, if you have any errors double check the paths and file names provided in the prior sections.

Add the Set License Code

With the project created and the frameworks installed, the set license code can be added.

Open the ViewController.swift file. Below the existing viewDidLoad() section, create a new override func called viewDidAppear(_ animated: Bool). Like the above viewDidLoad(), these are different states in the app loading process.

override func viewDidLoad() { 
	// Do any additional setup after loading the view. 
override func viewDidAppear(_ animated: Bool) { 

Next, create a new standard func called showAlert(message: String, title: String). This function is called from the SetLicense() function and is responsible for displaying pop-up style messages in the App UI.

func showAlert(message: String, title: String) { 
	let alert = UIAlertController(title: title, message: message, preferredStyle: .alert) 
	alert.addAction(UIAlertAction(title: "Ok", style: .default, handler: nil)) 
	self.present(alert, animated: true) 

Lastly, create a new func called SetLicense() and call it inside the viewDidAppear fucntion, as shown above. Add the following code to properly set your LEADTOOLS license.

func SetLicense() { 
	let license = "/path/to/LEADTOOLS22/Support/Common/License/Leadtools.lic" 
	let keyFile = String("\(license).key") 
	do { 
		let key = try String(contentsOfFile: keyFile) 
		try LTRasterSupport.setLicense(file: license, developerKey: key) 
	} catch { 
		print("Unable to read contents of .key file.") 
	if LTRasterSupport.kernelExpired { 
		print("License file invalid or expired.") 
		showAlert(message: "License file invalid or expired.", title: "Leadtools") 
	} else { 
		print("License file set successfully!") 
		showAlert(message: "License file set successfully", title: "Leadtools") 

Run the Project

Clean the project to clear any errors by selecting Product -> Clean Build Folder or Shift + Command + K.

Run the project by selecting Product -> Run or Command + R.

If the steps were followed correctly, the app will launch and a message should appear showing "License file set successfully".

Screenshot of Output message.


This tutorial showed how to create a new Swift iOS project, add LEADTOOLS Frameworks and Header files, and set the license.

This is the basis for all Swift iOS applications leveraging the LEADTOOLS SDK. All functionality in the SDK is unlocked via setting a license. The setLicense() function must be called before calling any other LEADTOOLS SDK functions.

Once the SDK is purchased, the evaluation license can be replaced with a valid runtime license to disable the Nag Message.

See Also

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© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.

Products | Support | Contact Us | Intellectual Property Notices
© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.