This guide explains how to implement system specific functions

• Capture the events when an application enters the background or foreground
• Explains the implementation of deep linking

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Examples

Please see the UgSystemDemo project for the source code created in this chapter. See Installing examples for information on how to download the examples.

Background and Foreground events

You need to override the onEnterForeground and onEnterBackground functions to capture the event when an applications enters the Foreground and Background

import ScadeKit

class UgSystemDemo: SCDApplication {

	let window = SCDLatticeWindow()
	let mainAdapter = MainPageAdapter()
	
	override func onFinishLaunching() {	
		mainAdapter.load("main.page")
		mainAdapter.show(window)
	}
	
	// Override method to capture background enter event
	override func onEnterBackground() {
    	print("onEnterBackground")
  	}

	// Override method to capture foreground enter event
  	override func onEnterForeground() {
    	print("onEnterForeground")
  	}
	
}

SCADE API uses the UIApplicationDelegate api on Apple, and the Activity class on Android to capture these system events.

Deep Linking

SCADE provides access to iOS and Android deep linking functionality using one API offered through the SCADE SDK.

You can create an app handler that reacts to any Deep Link call and provides the necessary data about the call.

Here some intro document references for optional reading, the below tutorial covers all the basics.

• Android https://developer.android.com/training/app-links/deep-linking
• iOS https://medium.com/@stasost/ios-how-to-open-deep-links-notifications-and-shortcuts-253fb38e1696

Getting started

A deep link consists of a project-uri followed by the rest of the link

You can use any string you want as project-uri BUT the string needs to be unique across all apps. We use ScadeDeepLinking as the project-uri.

Therefore the link to call any functionality on the app would be:

Add Deep Link information to build file

As a first step, you need to add information to the build file so that Android and iOS know about the fact that you want to use Deep Linking and register that information with Android and iOS.

Please add the following segment to the 'ios:' part of your build file

plist:
  - key: CFBundleURLTypes
    type: list
    values:
      - type: dict
        values:
          - key: CFBundleURLName
            type: string
            value: project-id
          - key: CFBundleURLSchemes
            type: list
            values:
              - type: string
                value: project-uri

And the following segment to the 'android:' part of your build file

intent-filters:
  - action: android.intent.action.VIEW
    scheme: project-uri
    categories: [android.intent.category.DEFAULT, android.intent.category.BROWSABLE]

Within the YAML, you need to make 3 modifications

• For iOS, set the value for CFBundleURLName
• For iOS, set the project-uri as the value for the CFBundleURLSchemes items array
• For Android, set the project-uri as the value set the scheme field

We marked the values you have to change in your app here:

Add code to handle incoming Deep Link calls

As a second step, you need to implement the code that is called when the deep link is invoked from outside. Goto the start.swift file and override the onOpen method:

Whenever the deep link is invoked, you receive the URL in the url parameter. The below code demos extracting the information from the URL and in this example informs the main window if the link contains a matching parameter name.

override func onOpen(with url: String) {
		
	if let ucs = URLComponents(string:url) {
			
    // The host value
    print(String(ucs.host!))

	// This is how to iterate the queryItems
	for qp in ucs.queryItems! {
	print(qp.name,String(qp.value!))
	}

	// lets search for a query parameter named msg and if it exists, inform window
	if let msg = ucs.queryItems!.first(where: { $0.name == "msg" } )  {
  	mainAdapter.newDeepLinkMsg(msg:msg.value!)
    }
}
}

Compile and test

Testing your deep link can only happen in iOS or Android simulator or app:

• You require Android API 23 or higher

Testing on iOS

1. run the app on iOS simulator.
2. Goto Safari and type scadedeeplinking://try?msg=ScadeRocks
3. our app will start up, and the message ScadeRocks will appear on the main screen

Testing on Android

Android doesn't allow direct deep link invocation via the browser. One way of testing deep links is using the adb:

1. run the app on Android simulator with API 23 or higher
2. Run the adb am command to invoke a deep link

./adb shell am start -a android.intent.action.VIEW -d "scadedeeplink://try?msg=ScadeRocks" com.scade.ugsystemdemo

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Deep Link testing on Android - ADB AM command for calling a deep link

./adb shell am start -a android.intent.action.VIEW -d "scadedeeplink://try?msg=ScadeRocks" com.scade.ugsystemdemo

Its important that com.scade.ugsystemdemo MUST be lowercase

Gotchas

Here some hints of possible mistakes you might have made if things aren't working

Check .build file

You might have a typo in the .build file. In case of a typo, the compiler information for cmake is not created correctly.

1. Check the .build file for typos
2. Check the CMakeList.text file. Make sure they contain the correct entries. These are autogenerated after compiling to iOS/Android. The highlighted section contains the entries needed for deep linking: