app

Extends NativeObject

Provides information about the application.

Import this object with “const {app} = require('tabris');”

Example:

app.on("pause", () => pauseVideo());

Methods

getResourceLocation(path)

Parameters:

• path: string
  • the path of a resource relative to the application root.

Returns: string

Returns the URL for a given resource that is bundled with the app. Can be used to access app resources like images, videos, etc. Note that these resources can only be accessed in read-only mode.

installPatch(url, callback)

Parameters:

• url: string
  • the URL to fetch a patch from.

• callback: *(error: Error

  null, patch: any

  null) => void*

  • a callback function to be called when the installation has finished or failed. In case of a failure, the callback will receive a parameter error that contains an Error object. If the installation succeeds, this parameter will be null and a second parameter will contain the parsed content of the file patch.json from the installed patch.

Note: this API is provisional and may change in a future release.

Installs a patch from the given URL. When the patch is successfully installed, it will remain inactive until the application is reloaded. Not supported on Windows.

reload()

iOSAndroid

Forces the running application to reload the main module and start over.

Properties

id

Type: string

Uniquely identifies the app.

pinnedCertificates

Type: any[]

Enables certificate pinning for HTTP requests. When pinned certificates are defined for a host, connections to this host will only be permitted if the server provides a matching certificate. Connections to hosts that are not in the list are not affected.

Certificate pinning affects the following components: XHR/fetch, WebSockets, image loading and app patching. It does not affect WebViews.

The list of pinned certificates has to be in the form of [{host: <string>, hash: <string>, algorithm: <RSA2048|RSA4096|ECDSA256>}, ..].

• The host attribute denotes the host name (including subdomain) of the host to be pinned (wildcards allowed).
• The hash attribute is the base64 encoded sha256 fingerprint of the subjectPublicKeyInfo, prefixed with sha256/.
• The algorithm attribute denotes the public key algorithm of the SSL certificate and can have the values RSA2048, RSA4096 or ECDSA256. This attribute is only required on iOS.

Example: [{host: 'freegeoip.net', hash: 'sha256/+SVYjThgePRQxQ0e8bWTQDRtPYR/xBRufqyMoeaWteo=', algorithm: 'ECDSA256'}]

For further details see https://www.owasp.org/index.php/Certificate_and_Public_Key_Pinning.

version

Type: string

The user facing version number, e.g. ‘2.1-beta3’.

versionCode

Type: number

An alternative version number used in app stores to identify different versions of an app. Usually incremented with each release. This property reflects the versionCode on Android and CFBundleVersion on iOS.

Events

background

Fired when the app becomes invisible. Either because another app is in the foreground or the user has returned to the home screen.

backNavigation

Fired when the back button is pressed on Android.

Event Parameters

• target: this The widget the event was fired on.

• preventDefault: () => void Call to suppress the default back navigation behavior.

foreground

The event is fired when the app starts or when it returns from the background.

idChanged

Fired when the id property has changed.

Event Parameters

• target: this The widget the event was fired on.

• value: string The new value of id.

pause

Fired when the app is not the interaction target of the user anymore. Usually preceded by resume.

pinnedCertificatesChanged

Fired when the pinnedCertificates property has changed.

Event Parameters

• target: this The widget the event was fired on.

• value: any[] The new value of pinnedCertificates.

resume

Fired when the app is visible and ready to interact with the user. The event is preceded by either foreground (the app becomes visible again) or pause (the app regains ability to interact with user).

terminate

iOSAndroid

Fired when the app is being destroyed. After this callback no more interaction with the app is possible.

versionChanged

Fired when the version property has changed.

Event Parameters

• target: this The widget the event was fired on.

• value: string The new value of version.

versionCodeChanged

Fired when the versionCode property has changed.

Event Parameters

• target: this The widget the event was fired on.

• value: number The new value of versionCode.

Example

const {Composite, TextView, Button, app, ui} = require('tabris');

// React to application hibernation, resume and back navigation

let paused = 0;

createTextView('Id', app.id);
createTextView('Version', app.version);
createTextView('Version Code', app.versionCode);

new Composite({
  left: 0, top: 'prev() 16', right: 0,
  height: 1,
  background: '#E8E8E8'
}).appendTo(ui.contentView);

let label = new TextView({
  left: 16, top: 'prev() 16', right: 16,
  font: 'italic 14px',
  text: 'You can press home and reopen the app to it to see how long you were away.'
}).appendTo(ui.contentView);

new Button({
  left: 16, right: 16, bottom: 16,
  text: 'Reload app'
}).on('select', () => app.reload())
  .appendTo(ui.contentView);


app.on('pause', () => paused = Date.now())
  .on('resume', () => {
    if (paused > 0) {
      let diff = Date.now() - paused;
      label.text = ' Welcome back!\n You were gone for ' + (diff / 1000).toFixed(1) + ' seconds.';
    }
  });

app.on('backNavigation', (event) => {
  event.preventDefault();
  label.text = 'Back navigation prevented.';
});

function createTextView(key, value) {
  let composite = new Composite({left: 16, top: 'prev() 8', right: 16}).appendTo(ui.contentView);
  new TextView({text: key}).appendTo(composite);
  new TextView({text: value, left: 128}).appendTo(composite);
}