Extend Your MDK App With a Map Custom Control (Using Metadata Approach)

This step includes creating the mobile development kit project in the editor.

1. Launch the Dev space in SAP Business Application Studio.

2. Click Start from template on the Get Started page.

   

   If you do not see the Get Started page, you can access it by typing >get started in the center search bar.

   

3. Select MDK Project and click Next.

   

   If you do not see the MDK Project option check if your Dev Space has finished loading or reload the page in your browser and try again.

   This screen will only show up when your CF login session has expired. Enter your login credentials, click Sign in. After successful signed in to Cloud Foundry, select your Cloud Foundry Organization and Space where you have set up the initial configuration for your MDK app and click Apply.

   

4. In Basic Information step, provide the below information and click Next:

   Field	Value
   MDK Template Type	Choose List Detail from the dropdown
   Your Project Name	Provide a name of your choice. MDK_Maps is used for this tutorial
   Your Application Name	<default name is same as project name, you can provide any name of your choice>
   Target MDK Client Version	Leave the default selection as MDK 6.0+ (For use with MDK 6.0 or later clients)
   Choose a target folder	By default, the target folder uses project root path. However, you can choose a different folder path

   

5. In Service configuration step, provide the below information and click Next:

   Field	Value
   Data Source	Select Mobile Services from the dropdown
   Mobile Services Landscape	Select standard from the dropdown
   Application Id	Select com.sap.mdk.demo from the dropdown
   Destination	Select SampleServiceV2 from the dropdown
   Enter a path to the OData service	Leave it as it is
   Enable Offline	Choose No

   

   Regardless of whether you are creating an online or offline application, this step is needed app to connect to an OData service. When building an Mobile Development Kit application, it assumes the OData service created and the destination that points to this service is set up in Mobile Services and SAP Business Technology Platform.

   Since you will create an online based app, hence Enable Offline Store option is unchecked.

6. In Data Collections step, select Customers (if not selected by default). Click Finish to finish the project creation.

   

7. After clicking Finish, the wizard will generate your MDK Application based on your selections. You should now see the MDK_Maps project in the project explorer.

The extension control that you will be creating to extend the functionality of your app can be used as base controls by registering it using the MDK editor.

1. Download this image and save it locally. This image will be used as a display image on the page editor to represent the extension control.

2. Drag & drop map.png file on Images folders.

   

3. Right-click Extensions | select MDK: Register Extension Control.

   

4. In the Template Selection step, select New Metadata Extension Control. Click Next.

   

5. In the Base Information step, provide the below information and click Next.

   Field	Value
   Control Name	mdk_maps
   Module	MyMapModule
   Control	MyMapExtension
   Class	MyMapClass
   Display	click on the link icon and bind it to map.png file

   Here is the basic definition for properties you defined above:

   Module: It is used to identify the extension control.
   The path to the extension module under <MetadataProject>/Extensions/.

   Control: The name of the file under the <MetadataProject>/Extensions/<Module>/controls that contains the extension class. If not specified, module name would be used as the value for this property.

   Class: The class name of your custom extension class. The client will check for this class at runtime and if it’s found, your extension will be instantiated. Otherwise, a stub with an error message will be shown.

   Display: This property is used for the image to be displayed on the page editor to represent the extension control.

   

6. In the Extension Properties step, fill schema details in Schema column and click Finish.

   JSON

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   {
   	"type": "object",
   	"BindType": "",
   	"properties": {
   		"Prop": {
   			"type": "object",
   			"BindType": "",
   			"properties": {
   				"City": {
   					"type": "string",
   					"BindType": ""
   				},
   				"Country": {
   					"type": "string",
   					"BindType": ""
   				},
   				"HouseNumber": {
   					"type": "string",
   					"BindType": ""
   				},
   				"LastName": {
   					"type": "string",
   					"BindType": ""
   				},
   				"PostalCode": {
   					"type": "string",
   					"BindType": ""
   				},
   				"Street": {
   					"type": "string",
   					"BindType": ""
   				}
   			}
   		}
   	}
   }
   

   

   Above schema will add these predefined properties (City, Country, HouseNumber, LastName, PostalCode, and Street) in the map extension control which you will bind to Customer entity properties in next step.

   Some additional files and folders are added to the Extensions folder. You will learn more about it in following steps.

   

   You can find more details about registering extension control in this guide.

You will add this registered control in the generated Customers_Detail.page.

1. Navigate to Pages folder | Customers | Customers_Detail.page.

2. Remove the body section of the page.

   

3. Expand Section Registered Extension Control, drag & drop the registered mdk_maps control on the page area.

   

   You can find more details about the Section Extension in this guide.

4. In the Properties section, set the Height to 600.

   

5. Bind the registered Extension control properties to Customers properties.
   Under Extension Properties section, expand Prop, click the link icon to open the Object Browser for the City property. Double click the City property of the Customer entity to set it as the binding expression and click OK.

   

   Repeat the above step and bind other properties.

   

   Be careful not to bind properties from Address (ESPM.Address).

1. Navigate to Extensions | MyMapModule | controls | MyMapExtension.ts, replace the generated code with the following.

   JavaScript / TypeScript

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   import * as app from '@nativescript/core/application';
   import { IControl } from 'mdk-core/controls/IControl';
   import { BaseObservable } from 'mdk-core/observables/BaseObservable';
   import { EventHandler } from 'mdk-core/EventHandler'
   
   export class MyMapClass extends IControl {
       private _observable: BaseObservable;
       private _mapView: any;
       private _geo: any;
       private _gMap: any;
       private _marker: any;
       private _customerInfo = {
           lastName: "",
           houseNumber: "",
           street: "",
           city: "",
           country: "",
           postalCode: "",
           latitiude: "",
           longitude: ""
       }
   
       public initialize(props: any): any {
           super.initialize(props);
   
           //Access the properties passed from Customers_Detail.page to the extension control.
           //in this tutorial, you will be accessing the customer's last name and address
           if (this.definition().data.ExtensionProperties.Prop) {
               var property = this.definition().data.ExtensionProperties.Prop;
               this._customerInfo.lastName = property.LastName;
               this._customerInfo.houseNumber = property.HouseNumber;
               this._customerInfo.street = property.Street;
               this._customerInfo.city = property.City;
               this._customerInfo.country = property.Country;
               this._customerInfo.postalCode = property.PostalCode;
           }
   
           if (app.android) {
               //You will display the Google Maps in a MapView.For more details on Google Maps API for android, visit
               //https://developers.google.com/android/reference/com/google/android/gms/maps/package-summary
   
               this._mapView = new com.google.android.gms.maps.MapView(this.androidContext());
               var localeLanguage = java.util.Locale;
   
               //GeoCoder is required to convert a location to get latitude and longitude
               this._geo = new android.location.Geocoder(this.androidContext(), localeLanguage.ENGLISH);
               this._mapView.onCreate(null);
               this._mapView.onResume();
   
               //when mapview control is used, all the lifecycle activities has to be frowaded to below methods.
               app.android.on(app.AndroidApplication.activityPausedEvent, this.onActivityPaused, this);
               app.android.on(app.AndroidApplication.activityResumedEvent, this.onActivityResumed, this);
               app.android.on(app.AndroidApplication.saveActivityStateEvent, this.onActivitySaveInstanceState, this);
               app.android.on(app.AndroidApplication.activityDestroyedEvent, this.onActivityDestroyed, this);
               var that = this;
   
               //A GoogleMap must be acquired using getMapAsync(OnMapReadyCallback).
               //The MapView automatically initializes the maps system and the view
   
               var mapReadyCallBack = new com.google.android.gms.maps.OnMapReadyCallback({
                   onMapReady: (gMap) => {
                       console.log("inside onMapReady function");
                       that._gMap = gMap;
                       var zoomValue = 6.0;
                       that._gMap.setMinZoomPreference = zoomValue;
                       var customerAddress = that._customerInfo.houseNumber + ' ' + that._customerInfo.street + ' ' + that._customerInfo.city + ' ' +
                           that._customerInfo.country + ' ' + that._customerInfo.postalCode;
                       var data = that._geo.getFromLocationName(customerAddress, 1);
                       var latLng = new com.google.android.gms.maps.model.LatLng(data.get(0).getLatitude(), data.get(0).getLongitude());
                       that._gMap.addMarker(new com.google.android.gms.maps.model.MarkerOptions().position(latLng).title(this._customerInfo.lastName +
                           "'s " + "location"));
                       that._gMap.moveCamera(new com.google.android.gms.maps.CameraUpdateFactory.newLatLng(latLng));
                   }
               });
               this._mapView.getMapAsync(mapReadyCallBack);
           }
   
           if (app.ios) {
   
               /*initiating Apple Maps
               For more details on the Apple Maps visit
               https://developer.apple.com/documentation/mapkit */
               this._mapView = MKMapView.alloc().initWithFrame(CGRectMake(0, 0, 1000, 1000));
           }
       }
   
       private onActivityPaused(args) {
           console.log("onActivityPaused()");
           if (!this._mapView || this != args.activity) return;
           this._mapView.onPause();
       }
   
       private onActivityResumed(args) {
           console.log("onActivityResumed()");
           if (!this._mapView || this != args.activity) return;
           this._mapView.onResume();
       }
   
       private onActivitySaveInstanceState(args) {
           console.log("onActivitySaveInstanceState()");
           if (!this._mapView || this != args.activity) return;
           this._mapView.onSaveInstanceState(args.bundle);
       }
   
       private onActivityDestroyed(args) {
           console.log("onActivityDestroyed()");
           if (!this._mapView || this != args.activity) return;
           this._mapView.onDestroy();
       }
   
       //In case of iOS you'll use CLGeocoder API to convert an address to get latitude and longitude.
       //NOTE - API getlatlang is called only on ios devices
   
       private getlatlang(customerAddress) {
           const that = this;
           return new Promise((resolve, reject) => {
               var latLng = new CLGeocoder();
               latLng.geocodeAddressStringCompletionHandler(customerAddress, function (placemarks, error) {
                   if (error === null && placemarks && placemarks.count > 0) {
                       var pm = placemarks[0];
                       var cordinates = {
                           latitiude: "",
                           longitude: ""
                       }
                       cordinates.latitiude = pm.location.coordinate.latitude;
                       cordinates.longitude = pm.location.coordinate.longitude;
                       resolve(cordinates);
                   } else {
                       reject();
                   }
               });
           });
       }
   
       public view() {
           this.valueResolver().resolveValue([this._customerInfo.houseNumber, this._customerInfo.street, this._customerInfo.city, this._customerInfo
               .country, this._customerInfo.postalCode, this._customerInfo.lastName
           ], this.context)
               .then((address) => {
   
                   this._customerInfo.houseNumber = address[0];
                   this._customerInfo.street = address[1];
                   this._customerInfo.city = address[2];
                   this._customerInfo.country = address[3];
                   this._customerInfo.postalCode = address[4];
                   this._customerInfo.lastName = address[5];
   
                   var customerAddress = address[0] + ' ' + address[1] + ' ' + address[2] + ' ' + address[3] + ' ' + address[4];
                   console.log("customer's address = " + customerAddress);
   
                   if (app.ios) {
                       return this.getlatlang(customerAddress)
                           .then((cordinates) => {
                               /* below code is for the apple maps */
                               var latlong = CLLocationCoordinate2DMake(cordinates.latitiude, cordinates.longitude);
                               var annotation = MKPointAnnotation.alloc().init();
                               annotation.coordinate = latlong;
                               annotation.title = this._customerInfo.lastName + "'s" + " location";
                               this._mapView.centerCoordinate = latlong;
                               this._mapView.addAnnotation(annotation);
                           });
                   }
               });
   
           if (app.android) {
               return this._mapView;
           }
           if (app.ios) {
               return this._mapView;
           }
       }
   
       public viewIsNative() {
           return true;
       }
   
       public observable() {
           if (!this._observable) {
               this._observable = new BaseObservable(this, this.definition(), this.page());
           }
           return this._observable;
       }
   
       public setContainer(container: IControl) {
           // do nothing
       }
   
       public setValue(value: any, notify: boolean, isTextValue?: boolean): Promise<any> {
           // do nothing
           return Promise.resolve();
       }
   }
   

   In your import function, if you see errors related to @nativescript/core or mdk-core, you can ignore them. There is currently no reference of such libraries in the MDK editor.

2. Save the MyMapExtension.ts file.

So far, you have learned how to build an MDK application in the SAP Business Application Studio editor. Now, you will deploy the application definitions to Mobile Services to use in the Mobile client.

1. Right-click Application.app and select MDK: Deploy.

   

2. Select deploy target as Mobile Services.

   

   If you want to enable source for debugging the deployed bundle, then choose Yes.

   

   You should see Deploy to Mobile Services successfully! message.

   

   When deploying from VS Code to App Update and using an MDK 6.0+ client, you need to set the TS Target to use es6 instead of the default es5 version. See below for the setting in VS Code where you change it for es6.
   

   

Since you will display the customer’s address in Google Maps on Android device, you will need to provide an API key in generated MDK project (step 8).

1. Visit the Google Cloud Platform Console.

2. Click the project drop-down and select or create a new project for which you want to add an API key.

   

3. Click Maps SDK for Android API.

   

4. Click ENABLE.

   

5. Open Credentials console, click CREATE CREDENTIALS and click API Key.

   

6. Copy this generated key and save it locally. This will be required in step 7.

For iOS, you can just use the App store client. Continue with next step.

For Android, you will pass the API key to the MDK client, there is no way public store client can access it, hence you will create a branded client using MDK SDK or SAP Cloud Build Service.

1. Follow steps 1 to 3 from this tutorial.

2. Create below file structure under DemoSampleApp.mdkproject.

       DemoSampleApp.mdkproject
         ├── App_Resources_Merge
             └── Android
                 ├── app.gradle
                 └── src
                     └── main
                         └── AndroidManifest.xml
   

   

   Files specified in the .mdkproject/App_Resources_Merge folder override a part of the files in <generated-project>/app/App_Resources. You can find more details about it in help documentation.

3. Provide below information in the app.gradle file. Save the changes.

   Java

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   dependencies { implementation 'com.google.android.gms:play-services-maps:17.0.0' }
   

4. Provide below information in the AndroidManifest.xml file. Save the changes.

   XML

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   <?xml version="1.0" encoding="utf-8"?>
   <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="__PACKAGE__" xmlns:tools="http://schemas.android.com/tools" android:versionCode="1" android:versionName="1.0">
   	<!-- Always include this permission -->
   	<!-- This permission is for "approximate" location data -->
   	<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
   	<!-- Include only if your app benefits from precise location access. -->
   	<!-- This permission is for "precise" location data -->
   	<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
   	<!--
   	Required only when requesting background location access on
   	Android 10 (API level 29) and higher.
   	-->
   	<uses-permission android:name="android.permission.ACCESS_BACKGROUND_LOCATION" />
   	<application>
   		<meta-data android:name="com.google.android.geo.API_KEY" android:value="Enter your API Key generated in step 6" />
   	</application>
   </manifest>
   

5. Create your MDK client either using MDK SDK by following the step 4 from this tutorial OR using SAP Cloud Build Service by following this tutorial.

Make sure you are choosing the right device platform tab above.