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Question

I'm working at a Notification provider for my Android application with a WebView that uses a JavaScriptInterface to get info from a remote Javascript file that according to received info from the server, it triggers my application to send a heads up notification.

So, I've added a JavaScript Interface into the onCreate void:

OnomeWebContainer.addJavascriptInterface(new WebAppInterface(this), "Android");

And created the WebAppInterface class

// Interfacing with Javascript Code
public class WebAppInterface {
    Context mContext;

    WebAppInterface(Context c) {
        mContext = c;
    }

    @JavascriptInterface
    public void showTempHumUnavailableNotification(String toast) {
        OnomeTempHumUnavailableNotification();
    }

    @JavascriptInterface
    public void showSecurDudeAlertNotification(String toast) {
        OnomeSecurDudeAlertNotification();
    }
}

The JavaScript File triggers the notification when a certain file is not available on the remote server.

function showDHT11Alert() {
$.ajax({
    url: 'http://serveraddress/OnomeWeb/resources/data/tmp/onomeDHT11On',
    success: function () {
        $('#onomenotif_DHT11Unavailable').hide();
    },
    error: function () {
        $('#onomenotif_DHT11Unavailable').show();
        showDHT11Toast();
    },
});
}

function showDHT11Toast(toast) {
        Android.showTempHumUnavailableNotification(toast);
}

The notification provider works perfecly, even if the app is in background, but obviously if I close the app from the recent apps screen, the notification provider stops working. Now I'd like to make this JavaScript Interface working in a background service, even if the app is closed from the recent apps.

The background service should be the best solution to my problem, but how can I interface this with the main WebView? Is this possible?

Answer 1

The background service should be the best solution to my problem, but how can I interface this with the main WebView? Is this possible?

Unfortunately its not possible. The JavaScriptInterface is injected by your app by calling

OnomeWebContainer.addJavascriptInterface(new WebAppInterface(this), "Android");

And its only available to your WebView. Other WebViews won't inject it and as a result won't be able to trigger your showTempHumUnavailableNotification