Android Webview

Android WebView application example

This example can be used to open any Web SDK example page like in a browser. To open the page, the URL should be set

MCU Client example opened in Android Webview in audio only conference mode looks as follows

Analyzing the example code

To analyze the code take MainActivity.java and WebViewActivity.java classes of the webview-example application, which is available in build 1.1.0.26.

1. Launch WebViewActivity with URL entered

code

button = (Button) findViewById(R.id.btnUrl);
button.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        EditText et = (EditText) findViewById(R.id.textUrl);
        String url = et.getText().toString();
        if (url.isEmpty()) {
            showDialog();
        } else {
            Intent intent = new Intent(context, WebViewActivity.class);
            intent.putExtra("url", url);
            startActivity(intent);
        }
    }
});

2. WebView settings configuration

code

WebSettings settings = webView.getSettings();

// Enable Javascript
settings.setJavaScriptEnabled(true);

// Use WideViewport and Zoom out if there is no viewport defined
settings.setUseWideViewPort(true);
settings.setLoadWithOverviewMode(true);

// Enable pinch to zoom without the zoom buttons
settings.setBuiltInZoomControls(true);

// Allow use of Local Storage
settings.setDomStorageEnabled(true);

if(Build.VERSION.SDK_INT > Build.VERSION_CODES.HONEYCOMB) {
    // Hide the zoom controls for HONEYCOMB+
    settings.setDisplayZoomControls(false);
}

// Enable remote debugging via chrome://inspect
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
    WebView.setWebContentsDebuggingEnabled(true);
}

3. SSL certificates error handler configuration

code

webView.setWebViewClient(new WebViewClient() {
    @Override
    public void onReceivedSslError(WebView view, final SslErrorHandler handler, SslError error) {

        final AlertDialog.Builder builder = new AlertDialog.Builder(view.getContext());
        String message = "SSL Certificate error.";
        switch (error.getPrimaryError()) {
            case SslError.SSL_UNTRUSTED:
                message = "The certificate authority is not trusted";
                break;
            case SslError.SSL_EXPIRED:
                message = "The certificate has expired";
                break;
            case SslError.SSL_NOTYETVALID:
                message = "The certificate is not yet valid.";
                break;
            case SslError.SSL_IDMISMATCH:
                message = "The cerificate ID is mismatch";
                break;
            case SslError.SSL_DATE_INVALID:
                message = "The certificate date is invalid";
                break;
            case SslError.SSL_INVALID:
                message = "The certificate is invalid";
                break;
        }
        builder.setTitle("SSL Cerificate Error");
        builder.setMessage(message);
        builder.setPositiveButton("Continue", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                handler.proceed();
            }
        });
        builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                handler.cancel();
            }
        });
        Log.d(TAG, "onReceivedSslError " + message);
        final AlertDialog dialog = builder.create();
        dialog.show();
    }
});

4. Camera and microphone access requesting handler configuration

code

webView.setWebChromeClient(new WebChromeClient() {
    @Override
    public void onPermissionRequest(final PermissionRequest request) {
        Log.d(TAG, "Request permissions: ");
        for (String res : request.getResources()) {
            Log.d(TAG, res);
        }
        WebViewActivity.this.runOnUiThread(new Runnable() {
            @TargetApi(Build.VERSION_CODES.LOLLIPOP)
            @Override
            public void run() {
                request.grant(request.getResources());
            }
        });
    }

    @Override
    public void onPermissionRequestCanceled(PermissionRequest request) {
        Log.d(TAG, "onPermissionRequestCanceled");
    }

});

5. Requesting camera and microphone access on activity start

code

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
    int hasCameraPermission = checkSelfPermission(Manifest.permission.CAMERA);
    int hasRecordPermission = checkSelfPermission(Manifest.permission.RECORD_AUDIO);
    List<String> permissions = new ArrayList<>();
    if (hasCameraPermission != PackageManager.PERMISSION_GRANTED) {
        permissions.add(Manifest.permission.CAMERA);
    }
    if (hasRecordPermission != PackageManager.PERMISSION_GRANTED) {
        permissions.add(Manifest.permission.RECORD_AUDIO);
    }
    if (!permissions.isEmpty()) {
        requestPermissions(permissions.toArray(new String[permissions.size()]), 111);
    }
}

6. URL opening

code

webView.loadUrl(url);