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Native Function API Developer's Guide:Native Function APIs for iOS > iOS Quick Start Guide

iOS Quick Start Guide

Introduction

Follow these instructions to create a simple Iris application that uses the Native Function APIs for iOS.

Prerequisites

The following are the prerequisites to use Native APIs:

  • A computer running a recent version of Mac OS.
  • Xcode and a configured emulator or device. The Volt MX Iris Preview app can not be used to run this application.
  • Some knowledge of Objective C development.

How to

The purpose of the Native Function API is to call Apple iOS APIs directly within your JavaScript code in Volt MX Iris. Here is an example of a very simple Objective C program, which you can convert into a Volt MX Iris Application following these steps.

The iOS code

            #import "ViewController.h"

@interface ViewController()@end@implementation ViewController

- (void) viewDidLoad { [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    NSString * format = [NSString stringWithFormat: @"Hello %@ !! Enjoy your day", @"World"]
    NSLog(format);
} - (void) didReceiveMemoryWarning { [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}@end

This is a standard auto-generated Objective C project with the exception of this line:

            NSString *format = [NSString stringWithFormat:@"Hello %@ !! Enjoy your day.",@"World"]
  NSLog(format);

Compile and run this application in XCode, and note that it prints this string to the console:

Hello World!! Enjoy your day.

The code uses the format specifiers belonging to the NSString class to insert the word "World" into the output string.

Now do the same thing from JavaScript in Iris.

The JavaScript Project

  1. Create a New Project in Iris.
  2. Add the iOS Foundation framework for to the project.
  3. Add a form to your project.
  4. Add a button and a label to the form.
  5. Add a JavaScript module to the project.

  6. In the JavaScript module, create this function, wherefrmMain is the name of your form, and log is the name of your label.

       function testNativeFunctionAPI(){
   var NSString = objc.import("NSString");
   var format = NSString.stringWithFormat("Hello %@ !! Enjoy your day"  ,["World"]);
   frmMain.log.text = format;
   }

  7. Set the onClick action of the button to call testNativeFunctionAPI.

  8. Build and run your application in the iOS emulator or on a device.You can not run the application using the Volt MX Iris App.

What just happened?

The two important lines in the code are:

            var NSString = objc.import("NSString");
  var format = NSString.stringWithFormat("Hello %@ !! Enjoy your day",["World"]);

The first line imports the NSString class from the iOS API, and creates a handle, assigned to the JavaScript variable NSString. The second line calls the static member function stringWithFormat, which is used to insert the text "World" into your output string.

The format string is then assigned to the text value of the label on the form.