# Titanium.Android.Service
Android application component that executes in the background.
# Overview
A service is a component started by an application that runs in the background. The service does not have any application UI associated with it, so the user does not directly interact with it, only your application.
The Titanium SDK gives you the ability to write your own Android Services using JavaScript. The service executes your JavaScript code at intervals you specify. Note that the service may stop running if the application is killed.
To create a service:
- Write the JavaScript code you want the service to execute in a separate file. The service can execute any Titanium APIs but you should only use non-UI APIs.
- Register the service in your
tiapp.xml
file. Refer to the example below. - Create a service intent by passing the JavaScript file to
the Titanium.Android.createServiceIntent method and set the interval to run the
code using the intent's
putExtra()
method. - Pass the Intent object to either the Titanium.Android.createService method
to create a
Service
object (bound service), where the application can manage the service by invoking methods and binding callbacks on the object, or to the Titanium.Android.startService method to start the service (started service) and the service manages itself.
Use the Titanium.Android.Service
API to manage the service.
To get a reference to the Service
inside the JavaScript service code, use the
Titanium.Android.currentService property to retrieve a reference to the service,
then invoke the Titanium.Android.Service
APIs on the Service
object.
Further Reading:
# Background Location Service Example
In order to obtain location events while the application is backgrounded a foreground service must be used. Below is an example of a simple background location service.
tiapp.xml:
<android>
<manifest>
<uses-permission android:name="android.permission.ACCESS_BACKGROUND_LOCATION"/>
<uses-permission android:name="android.permission.FOREGROUND_SERVICE"/>
</manifest>
<services>
<service url="locationService.js"/>
</services>
</android>
locationService.js:
console.log(`Background location service started.`);
// Create foreground service.
Ti.Android.currentService.foregroundNotify(
123,
Ti.Android.createNotification({
contentTitle: "Background Location Service",
contentText: "Obtaining location data...",
contentIntent: Ti.Android.createPendingIntent({
intent: Ti.App.Android.launchIntent || Ti.Android.createIntent(),
})
}),
Ti.Android.FOREGROUND_SERVICE_TYPE_LOCATION
);
app.js:
const win = Ti.UI.createWindow({ backgroundColor: 'gray', layout: 'vertical' });
const backgroundServiceBtn = Ti.UI.createButton({ title: 'START BACKGROUND SERVICE' });
const listView = Ti.UI.createListView();
let count = 1;
let service = null;
// Set accuracy to high
Ti.Geolocation.accuracy = Ti.Geolocation.ACCURACY_HIGH;
// Enable manual configuration via location providers.
Ti.Geolocation.Android.manualMode = true;
// Define a location provider.
Ti.Geolocation.Android.addLocationProvider(
Ti.Geolocation.Android.createLocationProvider({
name: Ti.Geolocation.Android.PROVIDER_GPS,
minUpdateDistance: 0,
minUpdateTime: 5000
})
);
function getLocation () {
// Create location event listener.
Ti.Geolocation.addEventListener('location', e => {
// Create new section for location data.
let section = Ti.UI.createListSection({ headerTitle: `#${count++} - ${new Date().toTimeString()}` });
if (e.success) {
if (e.coords) {
e = e.coords;
}
// Insert location data.
section.items = [
{ properties: { title: 'LOCATION:\n' + e.latitude + ', ' + e.longitude, color: 'green' } },
{ properties: { title: 'ALTITUDE:\n' + e.altitude, color: 'green' } },
{ properties: { title: 'ACCURACY:\n' + e.accuracy, color: 'green' } }
])
} else {
// Oops! Something bad happened.
section.items = [
{ properties: { title: 'ERROR:\n' + e.error, color: 'red' } }
];
}
// Add section to listView
listView.appendSection(section);
});
}
function startBackgroundLocationService() {
if (service) {
console.log('Starting background location service...');
service.start();
backgroundServiceBtn.title = 'STOP BACKGROUND SERVICE';
}
}
function stopBackgroundLocationService() {
if (service) {
console.log('Stopping background location service...');
service.stop();
backgroundServiceBtn.title = 'START BACKGROUND SERVICE';
}
}
win.addEventListener('open', () => {
// Request location permissions.
Ti.Geolocation.requestLocationPermissions(Ti.Geolocation.AUTHORIZATION_ALWAYS, e => {
if (e.success) {
getLocation();
} else {
alert('Could not obtain location permissions.');
}
});
});
backgroundServiceBtn.addEventListener('click', () => {
if (!service) {
// Create background location service.
const intent = Ti.Android.createServiceIntent({ url: 'locationService.js' });
service = Ti.Android.createService(intent);
// Android 10+ request background location permissions.
if (parseInt(Ti.Platform.version.split('.')[0]) >= 10) {
Ti.Android.requestPermissions([ 'android.permission.ACCESS_BACKGROUND_LOCATION' ], e => {
if (e.success) {
startBackgroundLocationService();
} else {
alert('Could not obtain background location permissions.');
}
});
} else {
startBackgroundLocationService();
}
} else {
stopBackgroundLocationService();
}
});
win.add([backgroundServiceBtn, listView]);
win.open();
# Examples
# Hello World Service
This example shows how to create a service in JavaScript. Your service code is included in its own JavaScript file.
In this example, the service reads data from the Titanium.Android.Intent which created it, to see what it should say besides "Hello World".
File: myservice.js:
var service = Titanium.Android.currentService;
var intent = service.intent;
var message = intent.getStringExtra("message_to_echo");
Titanium.API.info("Hello World! I am a Service. I have this to say: " + message);
Register the service in tiapp.xml:
<ti:app>
<android xmlns:android="http://schemas.android.com/apk/res/android">
<services>
<service url="myservice.js" type="interval"/>
</services>
</android>
</ti:app>
Code in "regular" Titanium file to launch the service and listen for pause/resume events. Code also stops the service after its code runs 3 times.
var intent = Titanium.Android.createServiceIntent( { url: 'myservice.js' } );
// Service should run its code every 2 seconds.
intent.putExtra('interval', 2000);
// A message that the service should 'echo'
intent.putExtra('message_to_echo', 'Titanium rocks!');
var service = Titanium.Android.createService(intent);
service.addEventListener('resume', function(e) {
Titanium.API.info('Service code resumes, iteration ' + e.iteration);
});
service.addEventListener('pause', function(e) {
Titanium.API.info('Service code pauses, iteration ' + e.iteration);
if (e.iteration === 3) {
Titanium.API.info('Service code has run 3 times, will now stop it.');
service.stop();
}
});
service.start();
Console Output:
[INFO] [29,1942] Service code resumes, iteration 1
[INFO] [70,2029] Hello World! I am a Service. I have this to say: Titanium rocks!
[INFO] [3,2070] Service code pauses, iteration 1
[INFO] [2,3915] Service code resumes, iteration 2
[INFO] [31,3961] Hello World! I am a Service. I have this to say: Titanium rocks!
[INFO] [5,3968] Service code pauses, iteration 2
[INFO] [2,5917] Service code resumes, iteration 3
[INFO] [27,5961] Hello World! I am a Service. I have this to say: Titanium rocks!
[INFO] [16,5980] Service code pauses, iteration 3
[INFO] [1,5981] Service code has run 3 times, will now stop it.
# Properties
# serviceInstanceId READONLY
A service can be started more than once -- this number (based on an incrementing integer) indicates which "start number" in the sequence the current service instance is.
# Methods
# foregroundCancel
Puts the service into the "background" state and removes its foreground notification.
If you call the foregroundNotify method to put the service into the "foreground" state, then you call this method to put the service back into the "background" state. This will also automatically remove the foreground service's notification that was put into the status bar.
Note that stopping a foreground service will remove its foreground notification from the status bar as well. So, you do not have to call this method to remove it. This method is only intended to be used by services that need to dynamically change states.
Returns
- Type
- void
# foregroundNotify
Puts the service into the "foreground" state and displays a notification.
Calling this method will change the service from the "background" state (the default) to the "foreground" state. It will also post a notification to the status bar to notify the end-user that the app is doing work, even while backgrounded. This feature is typically used by apps that play music, monitor current location, or perform large downloads while the app is in the background.
Note that a foreground service is far less likely to be terminated by the operating system while the app is in the background. A foreground service is also needed if the app needs to acquire location data since Android 8.0 and higher throttles location acquisition while the app is in the background.
See Android 8.0 "Background Execution Limits":
- https://developer.android.com/about/versions/oreo/background
You can call this method before or after the service has been started. If you need to change the displayed notification, then you can call this method again with the same notification ID and with an updated [notification]Titanium.Android.Notification object.
The notification will be automatically removed from the status bar when the service has been stopped or if you call the foregroundCancel method.
This method will fail on Android 9.0 and above unless you set the following Android manifest permission in your "tiapp.xml" file.
<ti:app>
<android xmlns:android="http://schemas.android.com/apk/res/android">
<manifest>
<uses-permission android:name="android.permission.FOREGROUND_SERVICE"/>
</manifest>
</android>
</ti:app>
Parameters
Name | Type | Description |
---|---|---|
id | Number | Unique integer ID to be assigned to the notification. Cannot be zero. |
notification | Titanium.Android.Notification | Notification to display in the status bar. Cannot be null. |
foregroundServiceType | Number | Notification service type specified by <Titanium.Android.FOREGROUND_SERVICE_TYPE_*>. |
Returns
- Type
- void
# start
Starts the Service.
Effective only if this instance of Titanium.Android.Service was created with createService.
Returns
- Type
- void
# Events
# pause
For Javascript-based services that you create, pause
fires after each time the JavaScript
code executes.
The resume
and pause
events occur in pairs, with resume
firing just before your
JavaScript service code executes, and pause
just after.
Properties
Name | Type | Description |
---|---|---|
iteration | Number | Incrementing integer indicating which iteration of an interval-based Service is pausing. For example, if you have an interval-based Service running every 10 seconds, iteration 3 would occur at about 30 seconds after you start the instance (assuming your service code runs quickly). |
source | Object | Source object that fired the event. |
type | String | Name of the event fired. |
bubbles | Boolean | True if the event will try to bubble up if possible. |
cancelBubble | Boolean | Set to true to stop the event from bubbling. |
# resume
For JavaScript-based Services which you create, resume
fires each time the JavaScript
code executes.
For example, if your Service runs on an interval of 10000 (10 seconds), you would expect
to see resume
fired every 10 seconds, just as the JavaScript service code you wrote is
about to execute.
Properties
Name | Type | Description |
---|---|---|
iteration | Number | Incrementing integer indicating which iteration of an interval-based Service is pausing. For example, if you have an interval-based Service running every 10 seconds, iteration 3 would occur at about 30 seconds after you start the instance (assuming your service code runs quickly). |
source | Object | Source object that fired the event. |
type | String | Name of the event fired. |
bubbles | Boolean | True if the event will try to bubble up if possible. |
cancelBubble | Boolean | Set to true to stop the event from bubbling. |
# start
Fired when the bound service instance starts.
Bound service instances are created via createService.
# stop
Fired when the bound service instance stops.
The service stops when stop or stopService is called and there are no more bound, un-stopped clients.
# taskremoved
Fired when the task that comes from the service's application has been removed.
This event is fired if the service is currently running and the user has removed a task that comes from the service's application, eg. the user swipes the application away from the recent applications list. It only works for unbound service which is started using startService.