1. Device APIs with Xamarin
Device APIs with Xamarin
Accessing Phonebook, Location, Camera
Xamarin apps for iOS, Android & WinPhone
Telerik School Academy

2. Table of Contents Reference Xamarin.Mobile Accessing Device APIs*
Table of Contents
Reference Xamarin.Mobile
Accessing Device APIs
Geo location
Address book
Camera
(c) 2007 National Academy for Software Development - All rights reserved. Unauthorized copying or re-distribution is strictly prohibited.*

3. Xamarin.Mobile
Download Xamarin.Mobile or install through Components for each platform

4. Table of Contents Geo location Reference Xamarin.Mobile*
Table of Contents
Reference Xamarin.Mobile
Accessing Device APIs
Geo location
Address book
Camera
(c) 2007 National Academy for Software Development - All rights reserved. Unauthorized copying or re-distribution is strictly prohibited.*

5. Geolocation Shared Code
Add interface IGeolocator
Use DependencyServices to call methods
Use MessageingCenter to Subscribe to event
Public interface IGeolocator {
void GetPosition(); }
IGeolocator locator = DependencyService
.Get<IGeolocator>();
locator.GetPosition();
MessagingCenter.Subscribe<IGeolocator, AppPosition>(this, [matching string], DisplayPosition);

6. Geolocation Implementation
Add device implementation and use Dependency
[assembly: Dependency (typeof (Geolocator_Android))]
public class Geolocator_Android : Action, IGeolocator {
public GeoLocation GetPosition () {
var locator = new Geolocator(Forms.Context) {
DesiredAccuracy = 50 };
if (locator.IsListening != true) {
locator.StartListening(
minTime: 1000, minDistance: 0); }
var pos = await locator.GetPositionAsync(
timeout: 20000);
MessagingCenter.Send<IGeolocator, AppPosition>(
this, "gotLocation", new AppPosition(
pos.Latitude, pos.Longitude) });

7. Table of Contents Address book Reference Xamarin.Mobile*
Table of Contents
Reference Xamarin.Mobile
Accessing Device APIs
Geo location
Address book
Camera
(c) 2007 National Academy for Software Development - All rights reserved. Unauthorized copying or re-distribution is strictly prohibited.*

8. Address Book Shared Code
Add interface IContactsGetter
Use DependencyServices to call methods
Use MessageingCenter to Subscribe to event
Public interface IContactsGetter {
void GetPhonebook(); }
IContactsGetter contactsGetter = DependencyService
.Get<IContactsGetter>();
contactsGetter.GetPhonebook();
MessagingCenter
.Subscribe<IContactsGetter, IEnumerable<AppContact>>
(this, [matching string], DisplayContacts);

9. Address Book Implementation
Add device implementation and use Dependency
public async void GetPhonebook() {
var book = new AddressBook(Forms.Context);
var hasAccess = await book.RequestPermission();
if (hasAccess) {
List<AppContact> contacts = new List<AppContact>();
foreach (var c in book) {
contacts.Add(new AppContact() {
Name = c.DisplayName,
Number = c.Phones.FirstOrDefault().Number
}); }
MessagingCenter
.Send<IContactsGetter,IEnumerable<AppContact>>
(this, "gotContacts", contacts);
} }

10. Table of Contents Camera Reference Xamarin.Mobile*
Table of Contents
Reference Xamarin.Mobile
Accessing Device APIs
Geo location
Address book
Camera
(c) 2007 National Academy for Software Development - All rights reserved. Unauthorized copying or re-distribution is strictly prohibited.*

11. Camera Shared Code Add interface ITakePhoto Add assembly Dependency
Public interface ITakePhoto {
void TakePhoto(); }
IPhotoTaker picker = DependencyService
.Get<IPhotoTaker>();
picker.TakePhoto();
MessagingCenter
.Subscribe<IPhotoTaker, string>(
this, "photoTaken", PathPhotoTaken);

12. Camera Android (1) Add device implementation and use Dependency
public async void TakePhoto() {
var picker = new MediaPicker(Forms.Context);
var intent = picker.GetTakePhotoUI(new StoreCameraMediaOptions {
DefaultCamera = CameraDevice.Rear,
Directory = "DemoFolder",
Name = "myPic.jpg"
});
StartActivityForResult(intent, 1); }

13. Camera Android (2) Override OnActivityResult
protected async override void OnActivityResult(
int requestCode, Result resultCode, Intent data) {
if (resultCode == Result.Canceled)
return;
var mediaFile = await data
.GetMediaFileExtraAsync(Forms.Context);
MessagingCenter.Send<IPhotoTaker, string>(
this, "photoTaken", mediaFile.Path); }

14. Camera iOS Add interface and use the Xamarin.DependencyServices
using Xamarin.Media;
// ...
var picker = new MediaPicker();
picker
.PickPhotoAsync()
.ContinueWith (t => {
MediaFile file = t.Result;
Console.WriteLine (file.Path);
}, TaskScheduler.FromCurrentSynchronizationContext());

15. Device APIs with Xamarin

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