Alternative way for communication between WebView and native

Question

I am using WebView and a lot of JavaScript in my native application. If JS side wants to call native functions it\'s rather smooth using JavaScriptInterfa

Answer 1

I don't know how to get an alternate communication model working, but I think I've found a workaround for the loadUrl-hides-the-keyboard issue: https://stackoverflow.com/a/18776064/513038. Does that help any?

Answer 2

I have the following code which uses java reflection to call JavaScript from Java. It avoids the following loadUrl bugs: 1. loadUrl may hide keyboard when your focus in a input. 2. loadUrl cannot be called too often.

Hopefully this helps:

public class AdvancedWebView extends WebView {
    private static final int EXECUTE_JS = 194;
    Method sendMessageMethod;
    Object webViewCore;
    boolean initFailed = false;;
    InputMethodManager imm;


    public AdvancedWebView(Context context, AttributeSet attrs) {
        super(context, attrs);
        imm = (InputMethodManager) context.getSystemService(Context.INPUT_METHOD_SERVICE);
        this.getSettings().setJavaScriptEnabled(true);
        this.initReflection();
    }

    @SuppressWarnings("rawtypes")
    private void initReflection() {
        Object webViewObject = this;
        Class webViewClass = WebView.class;
        try {
            Field f = webViewClass.getDeclaredField("mProvider");
            f.setAccessible(true);
            webViewObject = f.get(this);
            webViewClass = webViewObject.getClass();
        } catch (Throwable e) {
            // mProvider is only required on newer Android releases.
        }       

        try {
            Field f = webViewClass.getDeclaredField("mWebViewCore");
            f.setAccessible(true);
            webViewCore = f.get(webViewObject);
            if (webViewCore != null) {
                sendMessageMethod = webViewCore.getClass().getDeclaredMethod("sendMessage", Message.class);
                sendMessageMethod.setAccessible(true);      
                System.out.println("sendMessageMethod-----"+sendMessageMethod);
            }
            hasIntercepted = true;
        } catch (Throwable e) {
            hasIntercepted = false;
            //Log.e(LOG_TAG, "PrivateApiBridgeMode failed to find the expected APIs.", e);
        }finally{
            if(sendMessageMethod == null)
            {
                hasIntercepted = false;
            }
        }
    }

    private void loadJs(String url) {
        if (sendMessageMethod == null && !initFailed) {
            initReflection();
        }
        // webViewCore is lazily initialized, and so may not be available right away.
        if (sendMessageMethod != null) {
            //String js = popAndEncodeAsJs();
            Message execJsMessage = Message.obtain(null, EXECUTE_JS, url);
            try {
                sendMessageMethod.invoke(webViewCore, execJsMessage);
            } catch (Throwable e) {
                //Log.e(LOG_TAG, "Reflection message bridge failed.", e);
            }
        }
    }
}