Question

Ok guys. What I’m trying to do: I’ve got some backend code written in javascript (the project was originally supposed to be a web-app) and I’ve added a javascript interface to my android web view, and when I press a button in my ui, the javascript code does some stuff, then calls a function in my javascript interface when it is done… The code from my javascript interface:

public void onReady() {
    backend.loadUrl("javascript:dokus.backend.onLoginStatusChange(Bridge.onLoginStatusChange);");
    backend.loadUrl("javascript:dokus.backend.onProjectsChange(Bridge.onProjectsChange);");
    backend.loadUrl("javascript:dokus.backend.onLatestEntriesChange(Bridge.onLatestEntriesChange);");
}

public void onLoginStatusChange (boolean loggedIn, String error) {
    Toast.makeText(mainActivity, "LoginStatusChange", Toast.LENGTH_SHORT).show();
}
...

I’ve already verified that the onReady function is called, so that’s not the problem.
The javascript function which calls onLoginStatusChange is this following:

function _login_callback(loggedIn, msg) {
    if (loggedIn) {
        _get_projects();
        _get_latest_entries();
    }

    console.log(_login_status_changed_callback);

    if (_login_status_changed_callback !== undefined)
        _login_status_changed_callback (loggedIn, msg);
}

The error i get is this: “Line: 180, type error”. That’s all i get from my WebChromeView function, that prints everything from console.log() to a toast message.

the console.log(_login_status_changed_callback) prints out the following:

function onLoginStatusChange () {
   [native code]
}

I’ve verified that the correct arguments are called to the function (a bool and a string), so that shouldn’t be the error either… I’m at a loss, what do i do?

setup code for the web view:

private void setupBackend () {
    final DokusActivity that = this;

    backend = new WebView(this);
    BackendBridge.getInstance().initInstance(this, backend);

    backend.getSettings().setJavaScriptEnabled(true);
    backend.getSettings().setDomStorageEnabled(true);
    backend.addJavascriptInterface(BackendBridge.getInstance(), "Bridge");

    backend.setWebViewClient(new WebViewClient() {
        public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
            Toast.makeText(that, "Oh no! " + description, Toast.LENGTH_SHORT).show();
        }
    });

    backend.setWebChromeClient(new WebChromeClient() {
        public boolean onConsoleMessage (ConsoleMessage consoleMessage) {
            Toast.makeText(that, "Oh no! " + consoleMessage.lineNumber() + ": " + consoleMessage.message(), Toast.LENGTH_SHORT).show();
            return false;
        }
    });

    backend.loadUrl("file:///android_asset/index.html");
}

Answer 1

Apparently, the webview has issues when you try to pass native functions as callbacks to other methods. What I did was create a new .js file which works as callbacks, all the js callbacks do, is calling the native method.