# iOS Hyperloop Programming Guide

This document provides information on iOS Hyperloop programming requirements, classes, instantiation, methods and properties, named methods, constants, enumerations, and functions, casting, blocks, function pointers, creating your own classes, using 3rd party libraries, and additional resources.

# Requirements

See Hyperloop Requirements for software requirements for using Hyperloop.

# Classes

Classes in Hyperloop map to the underlying classes defined in Objective-C. For example, if you have a class such as UIView defined in the UIKit framework, you would reference it using a standard require such as:

var UIView = require('UIKit/UIView');

This will return the UIView class object. Meaning, it’s not an instance of a UIView, but the UIView class itself (or in Objective-C parlance, the interface defined with @interface).

Once you have the Class reference returned from require, you can call normal JavaScript property and functions against it. Remember, at this point calling functions or properties against the class object above will be accessing Class level Objective-C methods (not instance level).

For example, you could get the layerClass of the UIView using the example:

var layerClass = UIView.layerClass;

# Instantiation

To instantiate a native Class and create an instance, you can use the normal alloc initstyle pattern from Objective-C:

var view = UIView.alloc().init();

Or, to simplify and make it more standard JavaScript convention, for default initializers you can use new:

var view = new UIView();

This is the equivalent of the alloc init example above. When constructing an instance using new, it will always call the default initializer that is designated as init. If you have a special initializer that takes arguments, you can use the following as you would in Objective-C:

var view = UIView.alloc().initWithFrame(CGRectMake(0, 0, 100, 100));

# Methods and properties

Methods in Objective-C are mapped to JavaScript functions. Properties in Objective-C are mapped to JavaScript property accessors.

For example:

@interface UIView : UIControl
@property UIColor * backgroundColor;
- (void)addSubview:(UIView *)view;
- (void)setColor:(UIColor *) forMyState:(MyState)state;

@end

Would map to the following in JavaScript:

view.backgroundColor = UIColor.redColor;
view.addSubview(label);
view.setColorForMyState(UIColor.redColor, MyState.TestState);

You can also use auto-generated property-setters like view.setBackgroundColor(). Note that methods with multiple arguments are simply concatenated by their signature. More examples of that behavior:

/** -- Simple methods with two arguments -- **/

// Native (Obj-C)
[myView insertSubview:anotherView atIndex: 0];

// Hyperloop (JavaScript)
myView.insertSubViewAtIndex(anotherView, index);

/** -- Complex methods with blocks -- **/

// Native (Obj-C)
[UIView.animateWithDuration:1000.0 animations:^{
  // Do animation
} completion:(BOOL finished)^{
  // Finished animation
}];

// Hyperloop
UIView.animateWithDurationAnimationsCompletion(1000.0, function animations () {
  // Do animation
}, function completion (finished) {
  // Finished animation
});

Note that for the animateWithDuration method in Hyperloop, you do not need to name the callbacks, but it improves the readability and is a well used JavaScript pattern.

# Named methods

If you have a selector with multiple parameters, the name of the function will be slightly different since JavaScript cannot receive multiple parameters as part of a function call. For example, to send a message with the selector addAttribute:value:range: you would use the function named addAttributeValueRange instead. Hyperloop will camel-case each receiver name in the selector and remove the ":" character to formulate the name of the method. Arguments should then be passed to the function in the same order as you would in Objective-C.

# Constants, enumerations, and functions

Constants, enumerations, and functions defined in the Framework are available in the Framework package. For example, to reference the enum UISemanticContentAttribute you would reference it such as:

var UISemanticContentAttributeUnspecified = require('UIKit').UISemanticContentAttributeUnspecified;
view.semanticContentAttribute = UISemanticContentAttributeUnspecified;

The constants, enumerations, and functions are read-only properties of the UIKit framework.

# Casting

Sometimes interfaces define generic return types such as NSObject or id and you will need to cast them to a different type to then reference methods and properties of the class. You can use the special class function cast on any Class to return a casted object. For example, suppose the result of the function returned an id but you know the implementation is actually a UIView. You could use the following:

var view = UIView.cast(object);
view.backgroundColor = UIColor.redColor;

Be careful with casting: If you cast an object which is actually something different, you will experience an error and likely a crash. You can also cast a Titanium UI-component into its equivalent. For example, this would work:

var tiView = Ti.UI.createView({
  backgroundColor : 'red'
});
var nativeView = UIView.cast(tiView);
console.log('color should be red', nativeView.backgroundColor);

# Blocks

Blocks in Hyperloop are translated into JavaScript callback-functions.

For example, to animate a view which normally takes a block:

UIView.animateWithDurationAnimationsCompletion(1.0, function() {
  view.layer.opacity = 0.0;
}, function(done) {
    // The animation has been completed
});

# Function pointers

Currently, function pointers are not currently supported in the latest version.

# Creating your own classes

Hyperloop provides you the ability to dynamically create your own Objective-C classes at runtime. Once created, these classes can be used as normal in either Hyperloop or passed to native calls. Let’s create a simple custom UIView:

var MyClass = Hyperloop.defineClass('MyClass', 'UIView');

This will create a new class in the Objective-C runtime named MyClass which will extend UIView which is equivalent to the following code:

@interface MyClass : UIView
@end

You can also pass an Array of Strings as the third argument which are the protocols to implement for the new class:

var MyView = Hyperloop.defineClass('MyClass', 'UIView', ['UIAppearance']);

You can now add methods:

MyView.addMethod({
  selector: 'drawRect:',
  instance: true,
  arguments: ['CGRect'],
  callback: function(rect) {
    // this code is executed when the drawRect: delegate is called
  }
});

Hyperloop supports the following set of properties for adding methods:

• arguments can be either an Array or String of argument types (which can be either Objective-C encoding types or general type names such as float or int).

• returnType can be a String return type (which can be either Objective-C encoding types or general type names such as float or int). If no return is required (a void return type), you can omit the returnType property altogether and void will be implied.

Another example with multiple arguments using simplified types:

MyView.addMethod({
  selector: 'foo:bar:hello:',
  instance: true,
  returnType: 'void',
  arguments: ['int', 'float', 'id'],
  callback: function(a, b, c) {
        // Invoked when the method is called
  }
});

Once you have defined your class, you would just instantiate it as normal.

var view = new MyView();

# Using third-party libraries

You can use Third-Party libraries in Hyperloop that are available in the dependency-manager CocoaPods (opens new window).

# CocoaPods

Hyperloop supports CocoaPods as a way to manage Third-party dependencies in your Hyperloop-enabled project.

You must first install CocoaPods if you do not already have it installed. You can install using: sudo gem install cocoapods

Once you have CocoaPods installed you can create a Podfile in your Titanium project directory such as:

Podfile

# This is required for CocoaPods 1.x
install! 'cocoapods',
         :integrate_targets => false

platform :ios, '8.0'
target 'MyProject' do
    pod 'JBChartView'
end

Note that MyProject would be replaced with the name of your Titanium project. The above example will use the JBChartView (opens new window) framework as a dependency.

That’s it! CocoaPods and the Hyperloop compiler will do the rest to manage pulling down the required dependencies, compiling them and integrating them into the Xcode build.

Let’s now use the imported project:

var JBBarChartView = require('JBChartView/JBBarChartView');
var chart = new JBBarChartView();
chart.minimumValue = 1;
chart.maximumValue = 100;

# Fix build error for mixed Bitcode frameworks in CocoaPods
post_install do |installer|
  installer.pods_project.targets.each do |target|
    target.build_configurations.each do |config|
      config.build_settings['ENABLE_BITCODE'] = 'NO'
    end
  end
end

# Custom frameworks and libraries

In addition to CocoaPods, you can include third-party or first-party custom code by including a reference in appc.js under the thirdparty property. For example, to include custom objective-c from the project’s src directory you could provide:

appc.js

module.exports = {
  hyperloop: {
    ios: {
      thirdparty: {
        'MyFramework': {
          source: ['src'],
          header: 'src',
          resource: 'src'
        }
      }
    }
  }
};

• The source property can be either an Array or String of source directories to include in the compile. This is optional.

• The header property can be either an Array or String of header directories to include in the compile. This is required.

• The resource property can be either an Array or String of resource directories to search for resources or files to compile (images, story boards, xibs, etc). These files will be flattened and copied directly into the root of the application and can be loaded with NSBundle.

To provide additional compiler flags, you can add them in the xcodebuild property of ios such as:

appc.js

module.exports = {
  hyperloop: {
    ios: {
      xcodebuild: {
        flags: {
          LIBRARY_SEARCH_PATHS: '../../src',
          OTHER_LDFLAGS: '-lMyLibrary'
        }
      }
    }
  }
};

Note that the "flags" key takes a relative path from the build/iphone directory.

# Using Swift

In addition to Objective-C, you can import third-party libraries written in Swift. Any *.swift files found in your src directories will automatically be compiled and available to use in your JavaScript just like Objective-C APIs.

# Customizing your Xcode build

You can further customize the Xcode build by defining an appc.js file in the root of your project. This project will provide some additional configuration which the Hyperloop compiler will read when invoking Xcode.

For example:

appc.js

module.exports = {
  hyperloop: {
    ios: {
      xcodebuild: {
        flags: {
          GCC_PREPROCESSOR_DEFINITIONS: 'foo=bar'
        }
      }
    }
  }
};

Any flags added to the xcodebuild property will be passed to xcodebuild . Any frameworks in the array provided will be automatically added to the xcode project. Note: Any referenced frameworks in your Hyperloop code are automatically added for you. However, this gives you even more control to custom your compile environment.

# Resources

Any Xcode resources that are found in your Resources folder (for Classic projects) or appfolder (for Alloy projects) will be automatically be compiled and/or copied to your application root directory. Any intermediate folders will be flattened automatically.

The following resources will be compiled automatically:

• Storyboard (*.storyboard)

• XC Data Model (*.xcdatamodel, *.xcdatamodeld, *.xcmappingmodel)

• Interface Builder (*.xib)

The other resources will be copied such as PNG files.

It is recommended that you place any platform specific files under Resources/iphone (Titanium classic) or app/assets/iphone (Alloy).