OpenCV iOS Hello {#tutorial_hello} ================ @prev_tutorial{tutorial_ios_install} @next_tutorial{tutorial_image_manipulation} | | | | -: | :- | | Original author | Charu Hans | | Compatibility | OpenCV >= 3.0 | Goal ---- In this tutorial we will learn how to: - Link OpenCV framework with Xcode - How to write simple Hello World application using OpenCV and Xcode. Linking OpenCV iOS ------------------ Follow this step by step guide to link OpenCV to iOS. -# Create a new XCode project. -# Now we need to link *opencv2.framework* with Xcode. Select the project Navigator in the left hand panel and click on project name. -# Under the TARGETS click on Build Phases. Expand Link Binary With Libraries option. -# Click on Add others and go to directory where *opencv2.framework* is located and click open -# Now you can start writing your application. ![](images/linking_opencv_ios.png) Hello OpenCV iOS Application ---------------------------- Now we will learn how to write a simple Hello World Application in Xcode using OpenCV. - Link your project with OpenCV as shown in previous section. - Open the file named *NameOfProject-Prefix.pch* ( replace NameOfProject with name of your project) and add the following lines of code. @code{.m} #ifdef __cplusplus #import #endif @endcode ![](images/header_directive.png) - Add the following lines of code to viewDidLoad method in ViewController.m. @code{.m} UIAlertView * alert = [[UIAlertView alloc] initWithTitle:@"Hello!" message:@"Welcome to OpenCV" delegate:self cancelButtonTitle:@"Continue" otherButtonTitles:nil]; [alert show]; @endcode ![](images/view_did_load.png) - You are good to run the project. Output ------ ![](images/ios_hello_output.png) Changes for XCode5+ and iOS8+ ----------------------------- With the newer XCode and iOS versions you need to watch out for some specific details - The *.m file in your project should be renamed to *.mm. - You have to manually include AssetsLibrary.framework into your project, which is not done anymore by default.