@essent/nativescript-webview-ext

@essent/nativescript-webview-ext

Extended WebView for NativeScript which adds "x-local"-custom-scheme for loading local-files, handle events between WebView and NativeScript, JavaScript execution, injecting CSS and JS-files. Supports Android 19+ and iOS9+.

NOTE: This extends and updates the excellent: https://github.com/Notalib/nativescript-webview-ext

npm install @essent/nativescript-webview-ext

Features

• Adds a custom-scheme handler for x-local:// to the webview for loading of resources inside the webview.
  • Note: This is not supported on iOS <11
• Adds support for capturing URLs.
  • This allows the app to open external links in an external browser and handle tel-links
• Added functions like:
  • executeJavaScript(code: string) for executing JavaScript-code and getting result.
  • executePromise(code: string) for calling promises and getting the result.
  • getTitle() returns document.title.
• Two-Way event listeners between NativeScript and WebView
  • From NativeScript to WebView
  • From WebView to NativeScript
• Adds functions to inject css- and javascript-files.
  • Into the current page.
  • Auto-injected on page load.
• Polyfills:
  • Promise
  • Fetch API (overrides Native API on Android to support x-local:// and file://)
• Allows alert, confirm and prompt with WkWebView.
• Supports:
  • Android 19+
  • iOS 11+: Full support
  • iOS <11: Partial support

Update minSdkVersion to 19 or higher

Android SDK 19 is required, update App_Resources/Android/app.gradle:

android {
  defaultConfig {
    minSdkVersion 19 // change this line
    generatedDensities = []
  }
  aaptOptions {
    additionalParameters "--no-version-vectors"
  }
}

Core support

Load in template like this:

<Page class="page" xmlns="http://schemas.nativescript.org/tns.xsd" xmlns:essent="@essent/nativescript-webview-ext">
    <ActionBar class="action-bar">
        <Label class="action-bar-title" text="Home"></Label>
    </ActionBar>

    <essent:WebViewExt src="https://nota.dk"></<essent:WebViewExt>
</Page>

Angular support

Import WebViewExtModule from @essent/nativescript-webview-ext/angular and add it to your NgModule.

This registers the element WebViewExt. Replace the <WebView> tag with <WebViewExt>

Vue support

Import @essent/nativescript-webview-ext/vue in your app entry file (likely app.js or main.js).

This registers the element WebViewExt. Replace the <WebView> tag with <WebViewExt>

Usage

Limitations

The custom-scheme handler for x-local:// is only supported by Android and iOS 11+

Custom-scheme support for iOS <11 was removed because of ITMS-90809.

API

NativeScript View

Property	Value	Description
readonly supportXLocalScheme	true / false	Is x-local:// supported? True on iOS >= 11 or Android, False on iOS < 11.
src		Load src
autoInjectJSBridge	true / false	Should the window.nsWebViewBridge be injected on loadFinishedEvent? Defaults to true
builtInZoomControls	true / false	Android: Is the built-in zoom mechanisms being used
cacheMode	default / no_cache / cache_first / cache_only	Android: Set caching mode.
databaseStorage	true / false	Android: Enable/Disabled database storage API. Note: It affects all webviews in the process.
debugMode	true / false	Android: Enable chrome debugger for webview on Android. Note: Applies to all webviews in App
displayZoomControls	true / false	Android: displays on-screen zoom controls when using the built-in zoom mechanisms
domStorage	true / false	Android: Enable/Disabled DOM Storage API. E.g localStorage
scrollBounce	true / false	iOS: Should the scrollView bounce? Defaults to true.
supportZoom	true / false	Android: should the webview support zoom
viewPortSize	false / view-port string / ViewPortProperties	Set the viewport metadata on load finished. Note: WkWebView sets initial-scale=1.0 by default.
limitsNavigationsToAppBoundDomains	false	iOS: allows to enable Service Workers Note: If set to true, WKAppBoundDomains also should be set in info.plist.

Function	Description
loadUrl(src: string): Promise	Open a URL and resolves a promise once it has finished loading.
registerLocalResource(resourceName: string, path: string): void;	Map the "x-local://{resourceName}" => "{path}".
unregisterLocalResource(resourceName: string): void;	Removes the mapping from "x-local://{resourceName}" => "{path}"
getRegisteredLocalResource(resourceName: string): void;	Get the mapping from "x-local://{resourceName}" => "{path}"
loadJavaScriptFile(scriptName: string, filepath: string)	Inject a javascript-file into the webview. Should be called after the loadFinishedEvent
loadStyleSheetFile(stylesheetName: string, filepath: string, insertBefore: boolean)	Loads a CSS-file into document.head. If before is true, it will be added to the top of document.head otherwise as the last element
loadJavaScriptFiles(files: {resourceName: string, filepath: string}[])	Inject multiple javascript-files into the webview. Should be called after the loadFinishedEvent
loadStyleSheetFiles(files: {resourceName: string, filepath: string, insertBefore: boolean}[])	Loads multiple CSS-files into the document.head. If before is true, it will be added to the top of document.head otherwise as the last element
autoLoadJavaScriptFile(resourceName: string, filepath: string)	Register a JavaScript-file to be injected on loadFinishedEvent. If a page is already loaded, the script will be injected into the current page.
autoLoadStyleSheetFile(resourceName: string, filepath: string, insertBefore?: boolean)	Register a CSS-file to be injected on loadFinishedEvent. If a page is already loaded, the CSS-file will be injected into the current page.
autoExecuteJavaScript(scriptCode: string, name: string)	Execute a script on loadFinishedEvent. The script can be a promise
executeJavaScript(scriptCode: string)	Execute JavaScript in the webpage. Note: scriptCode should be ES5 compatible, or it might not work on 'iOS < 11'
executePromise(scriptCode: string, timeout: number = 500)	Run a promise inside the webview. Note: Executing scriptCode must return a promise.
emitToWebView(eventName: string, data: any)	Emit an event to the webview. Note: data must be stringify'able with JSON.stringify or this throws an exception.
getTitle()	Returns a promise with the current document title.

Events

Event	Description
loadFinished	Raised when a loadFinished event occurs. args is a LoadFinishedEventData
loadProgress	Android only: Raised during page load to indicate the progress. args is a LoadProgressEventData
loadStarted	Raised when a loadStarted event occurs. args is a LoadStartedEventData
shouldOverrideUrlLoading	Raised before the webview requests an URL. Can cancelled by setting args.cancel = true in the ShouldOverrideUrlLoadEventData
titleChanged	Document title changed
webAlert	Raised when window.alert is triggered inside the webview, needed to use custom dialogs for web alerts. args in a WebAlertEventData. args.callback() must be called to indicate alert is closed.
webConfirm	Raised when window.confirm is triggered inside the webview, needed to use custom dialogs for web confirm boxes. args in a webConfirmEvent. args.callback(boolean) must be called to indicate confirm box is closed.
webConsole	Android only: Raised when a line is added to the web console. args is a WebConsoleEventData.
webPrompt	Raised when window.prompt is triggered inside the webview, needed to use custom dialogs for web prompt boxes. args in a webConfirmEvent. `args.callback(string
Events emitted from the webview	Raised when nsWebViewBridge.emit(...) is called inside the webview. args in an WebViewEventData

WebView

Inside the WebView we have the nsWebViewBridge for sending events between the NativeScript-layer and the WebView. Note: The bridge will only be available DOMContentLoaded or onload inside the WebView.

Function	Description
window.nsWebViewBridge.on(eventName: string, cb: (data: any) => void)	Registers handlers for events from the native layer.
window.nsWebViewBridge.off(eventName: string, cb?: (data: any) => void)	Unregister handlers for events from the native layer.
window.nsWebViewBridge.emit(eventName: string, data: any)	Emits event to NativeScript layer. Will be emitted on the WebViewExt as any other event, data will be a part of the WebViewEventData-object

Waiting for nsWebViewBridge to be available

    window.addEventListener("ns-bridge-ready", function(e) {
        var nsWebViewBridge = e.detail || window.nsWebViewBridge;

        // do stuff here
    });

Possible features to come:

• Cookie helpers?
• Share cache with native-layer?

Android

• Settings
  • AppCache?
  • User agent?

iOS

• Settings?

About Nota

Nota is the Danish Library and Expertise Center for people with print disabilities. To become a member of Nota you must be able to document that you cannot read ordinary printed text. Members of Nota are visually impaired, dyslexic or otherwise impaired. Our purpose is to ensure equal access to knowledge, community participation and experiences for people who're unable to read ordinary printed text.

License

Apache License Version 2.0