Develop Reference

How to intercept Android App Link into a WebView?

I'm trying to implement the following behavior into my Android App.
The app is a native app with some parts using WebView, in this WebView there is the possibility of using different payment methods.
If the user has the app of that bank installed I want to be able to open the corresponding app. In some cases, the website loaded into the WebView launch a specific intent:// that I can easily intercept and try to redirect the user to the app, but for the cases where the website use the new Android App link I'm not able to intercept them because they are normal https:// calls.
I tried to load the Android App link into Chrome and this way the app is opened.
My question at this point is how I can replicate the behavior of Chrome into my WebView??
I didn't find that much informations on this specific case besides the Android Documentation
Thanks for your help :)

You can intercept the url click by using custom WebViewClient for the webview.
1)Set the custom webview client for the webview
2)Override the below method and return true (you can do this based on particular url also. )
shouldOverrideUrlLoading(WebView view, WebResourceRequest request)
3)Override below method and handle the click and start the activity using either package name or playstore url with intent.
public void onLoadResource (WebView view,
String url)
WebView mWebView;
WebViewClient customWebClient = new WebViewClient(){
#Override
public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request){
//This can be modified based on the url . URL can be retrieved using request.getUrl()
return true;
}
#Override
public void onLoadResource(WebView view, String url){
if( url.equals("") ){
// launch playstore activity
final String appPackageName = "package name of the application"
try {
startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("market://details?id=" + appPackageName)));
} catch (android.content.ActivityNotFoundException anfe) {
startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("https://play.google.com/store/apps/details?id=" + appPackageName)));
}
}
}
}
mWebView.setWebViewClient(customWebClient);

WebViewClient not calling shouldOverrideUrlLoading

The problem is rather simple.
In the application we want to keep track of the current url being displayed. For that we use shouldOverrideUrlLoading callback from the WebViewClient by saving the url into a class field for every update. Here is the relevant code:
mWebView.getSettings().setJavaScriptEnabled(true);
mWebView.getSettings().setDomStorageEnabled(true);
mWebView.setWebViewClient(new WebViewClient() {
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
mCurrentUrl = url;
// If we don't return false then any redirect (like redirecting to the mobile
// version of the page) or any link click will open the web browser (like an
// implicit intent).
return false;
}
#Override
public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
...
}
});
mWebView.loadUrl(mInitialUrl);
However, there is at least one scenario, where the callback never gets triggered and the mCurrentUrl field doesnt get updated.
The url: https://m.pandora.net/es-es/products/bracelets/556000
Last updated url (shouldOverrideUrlLoading never gets called when clicking the product): https://m.pandora.net/es-es/products/bracelets
I have tried with callbacks like onPageStarted(), but the url also gets filtered and there doesn't seem to be an accessible one upstream since its protected code.
Reading android documentation about WebView I found this:
https://developer.android.com/guide/webapps/migrating.html#URLs
The new WebView applies additional restrictions when requesting resources and resolving links that use a custom URL scheme. For example, if you implement callbacks such as shouldOverrideUrlLoading() or shouldInterceptRequest(), then WebView invokes them only for valid URLs.
But still doesnt make sense since the above url is generic and should meet the standard.
Any alternative or solution to this?

When you click a product on that web page, it loads the new content in with JavaScript and updates the visible URL in the address bar using the HTML5 History APIs.
From the above MDN article:
This will cause the URL bar to display http://mozilla.org/bar.html, but won't cause the browser to load bar.html or even check that bar.html exists.
These are sometimes called single-page applications. Since the actual loaded page doesn’t change, the WebView callback for page loads isn’t called.
In case you know precisely what kind of HTTP request you want to intercept, you could use the shouldInterceptRequest callback that gets called for each request. It’s likely that the web application loads some data from an API, for example when a product is shown, which you could then detect.
If detecting this isn’t possible, but you’re in control of the web application, you could use the Android JavaScript interface to invoke methods within the Android application directly from the web page.
If you’re not in control of the loaded page, you could still try to inject a local JavaScript file into the web page and observe when the history APIs are used, then call methods in your Android application over the JS interface. I tried observing these events in Chrome with the method described in the previous link and it seems to work fine.

Maybe this helps someone, although the signature in the question is correct, but Android Studio suggests the following method signature:
public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
which then never called. It took me a while to notice that the right signature is:
public boolean shouldOverrideUrlLoading(WebView view, String url) {
Sorry if this not 100% fit the question, but I believe this may help someone in the same situation. It's not always easy to notice that the second parameter is different.

Please omit mWebView.getSettings().setDomStorageEnabled(true);
Then again try, if a new url found then will invoke shouldOverrideUrl()

I had the same problem like you, and I've finished with extending of WebViewChromeClient with listening for callback to
public void onReceivedTitle(WebView view, String title)
mWebView.setWebChromeClient(mSWWebChromeClient);
private WebChromeClient mSWWebChromeClient = new WebChromeClient() {
#Override
public void onReceivedTitle(WebView view, String title) {
super.onReceivedTitle(view, title);
if (!view.getUrl().equals(mCurrentUrl)) {
mCurrentUrl = view.getUrl();
//make something
}
}
};

For me the problem was below line -
mWebView.getSettings().setSupportMultipleWindows(true);
After removing it shouldOverrideUrlLoading was being called.

after stumbling on this problem and searching for solutions, I've found the one that worked perfectly for me
https://stackoverflow.com/a/56395424/10506087
override fun doUpdateVisitedHistory(view: WebView?, url: String?, isReload: Boolean) {
// your code here
super.doUpdateVisitedHistory(view, url, isReload)
}

Another approach you can try: Catch the url by javascript side. Initialize your webView with this:
webView.addJavascriptInterface(new WebAppInterface(getActivity()), "Android");
After page is completely loaded (You can use an algorithm to check this like this https://stackoverflow.com/a/6199854/4198633), then:
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
webView.evaluateJavascript("(function() {return window.location.href;})", new ValueCallback<String>() {
#Override
public void onReceiveValue(String url) {
//do your scheme with variable "url"
}
});
} else {
webView.loadUrl("javascript:Android.getURL(window.location.href);");
}
And declare your WebAppInterface:
public class WebAppInterface {
Activity mContext;
public WebAppInterface(Activity c) {
mContext = c;
}
#JavascriptInterface
public void getURL(final String url) {
mContext.runOnUiThread(new Runnable() {
#Override
public void run() {
//do your scheme with variable "url" in UIThread side. Over here you can call any method inside your activity/fragment
}
});
}
}
You can do something like that to get url, or anything else inside the page.

Add
webView.getSetting().setMixedContentMode(WebSettings.MIXED_CONTENT_ALWAYS_ALLOW);
then shouldOverrideUrl will be triggered.

onProgressChanged is always triggered when reloading, loading new page with userclick or XmlHttpRequest.
Compare the URL of previous load and the current load, you'll know it's reloading or loading a new page. This works perfect in my single page Web App.
First declare a global variable to store last URL.
String strLastUrl = null;
Then override onProgressChanged(WebView view, int progress)
mWebView.setWebChromeClient(new MyWebChromeClient(){
#Override
public void onProgressChanged(WebView view, int progress) {
if (progress == 100) {
//A fully loaded url will come here
String StrNewUrl = view.getUrl();
if(TextUtils.equals(StrNewUrl,strLastUrl)){
//same page was reloaded, not doing anything
}else{
//a new page was loaded,write this new url to variable
strLastUrl = StrNewUrl;
//do your work here
Log.d("TAG", "A new page or xhr loaded, the new url is : " + strLastUrl);
}
}
super.onProgressChanged(view, progress);
}
});
I've also tried above solutions, but most of them have issue in my case:
doUpdateVisitedHistory sometimes can not return correct url after "#" made by XmlHttpRequest.
My case is a single page web App. The web App uses javascript with
xhr to display new page when user click an item. For example, user is
currently at http://example.com/myapp/index.php , after clicking, the
browser url becomes
http://example.com/myapp/index.php#/myapp/query.php?info=1, but in
this case, doUpdateVisitedHistory returns
http://example.com/myapp//myapp/
onReceivedTitle doesn't work in my case because the response retrieved by XMLHttpRequest does not have <title></title> tag.
The JavascriptInterface method also works, but I'm afraid it will cause
security related issues with javascript.

public class AndroidMobileAppSampleActivity extends Activity {
/** Called when the activity is first created. */
String mCurrentUrl="";
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
WebView mWebView = (WebView) findViewById(R.id.mainWebView);
WebSettings webSettings = mWebView.getSettings();
webSettings.setJavaScriptEnabled(true);
mWebView.setWebViewClient(new MyCustomWebViewClient());
mWebView.setScrollBarStyle(View.SCROLLBARS_INSIDE_OVERLAY);
mWebView.loadUrl("https://m.pandora.net/es-es/products/bracelets/556000");
}
private class MyCustomWebViewClient extends WebViewClient {
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
mCurrentUrl = url;
Log.i("mCurrentUrl",""+mCurrentUrl);
view.loadUrl(url);
return true;
}
}
}
try this one...

logging HTTP request start and finish from embedded Android WebView

I'm looking for a way to log the requests and start/end times made by an embedded webview. I'm not able to find a way to do it so far other than rooting the phone and running tcpdump. That works for me, but I need to run this in the field, so that's not really viable. There are lots of ways to log the URL and start time, but I can't see the finish (or, bonus, the full response metadata).
shouldLoadResource could work if I could wrap the current request, but I'd have to fetch it myself with HTTP support in order to return it en masse, because there isn't enough API exposed to fully forward to the inner request. (I don't want to do that for a number of reasons, including that webview on devices doesn't use the same network stack as the HTTP classes, and because it will change the timing of subresources.)
I've been trying to find ways to turn on chromium_net debug flags to do this, but I can't figure out how do do that in the context of the WebView or system properties.
I would really rather not ship my own webcore to do this, but if needs must...

override method shouldInterceptRequest()
#Override
public WebResourceResponse shouldInterceptRequest(WebView view, String url) {
Log.d(LOG_TAG, "shouldInterceptRequest: " + url);
return super.shouldInterceptRequest(view, url);
}

In that case, you could also add a WebViewClient (see http://developer.android.com/reference/android/webkit/WebViewClient.html). Which would look something like
WebView webView.setWebViewClient(new MyWebViewClient());
.
.
.
public class MyWebViewClient extends WebViewClient
{
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url)
{
// Note time
// Return false to say we want the WebView to handle the url.
return false;
}
#Override
public void onPageFinished (WebView view, String url)
{
super.onPageFinished(view, url);
// Note time
}
}
Note that both shouldOverrideUrlLoading and onPageFinished are only called only for the main frame - they will not be called for iframes or framesets. But this should give you what you need.

Android WebView Protocol Handler

I am trying to develop an Android browser application using WebView which enables users to access content from a custom protocol. The custom protocol could be foobar://
I want to intercept all requests to this custom protocol. This means:
GET requests
POST requests
and I need to be able to hand the results of these operations back to the WebView.
The GET requests can be handled using shouldInterceptRequest (available from API level 11).
Now my problem is: How can I incercept and handle POST requests?
Nearly the same question has been asked here and here, however no solutions for their problems have been found.

have you tried overriding for the post method doing something like:
private class ViewerWebViewClient extends WebViewClient {
#Override
public void onPageFinished( WebView view, String url ) {
}
#Override
public boolean shouldOverrideUrlLoading( WebView view, final String url ) {
if(!url.contains(MYKEYWORD))
{
Toast.makeText(getActivity(),POSTING, Toast.LENGTH_LONG).show();
return true;
}
return super.shouldOverrideUrlLoading(view, url);
}
}
its just an idea. that maybe could help you.

shouldOverrideUrlLoading in WebView for Android not running

-Edit: Solution Found-
Figured it out after some heavy searching - one person (I literally mean one) said they instead used onPageLoad(); which worked perfectly for my purposes. The difference is that onPageLoad() runs later than shouldOverrideUrlLoading, but It doesn't make a difference in my code.
I'm trying to set up Twitter authorization with OAuth for an Android app, and thus far I can successfully send the user to the authorization URL, however, what I am trying to do now is intercept the redirect to the callback (which would just lead to a 404 error, our callback URL isn't going to have an associated page on our servers). What I'm attempting to do is check if the URL is our callback, then extract the OAuth Verifier from the URL. I setup my WebView with this code:
view = (WebView)findViewById(R.id.twitterWbVw);
view.setWebViewClient(new WebViewClient(){
#Override
public boolean shouldOverrideUrlLoading(WebView wView, String url)
{
String urlHolder;
String[] verifExtrctr;
urlHolder = url.substring(0, url.indexOf('?'));
System.out.println("url");
if(urlHolder.equalsIgnoreCase(CALLBACK_URL))
{
verifExtrctr = urlHolder.split("?");
verifExtrctr = verifExtrctr[2].split("=");
if(verifExtrctr[0].equalsIgnoreCase("oauth_verifier"))
{
params[5] = verifExtrctr[1];
return true;
}
else
{
System.out.println("Inocorrect callback URL format.");
}
}
else
{
wView.loadUrl(url);
}
return true;
}
});
view.loadUrl(urlAuthorize.toExternalForm());
Thing is even System.out.println("url");(which I'm using to debug)doesn't run! So I'm pretty much dry on ideas, and can't find anyone with a similar problem. The authorization URL goes through fine, and I can successfully authorize the app, however the redirect to the callback URL for some reason never get's intercepted. Any help would be appreciated, this is in my onResume() if that matters.

After some research I conclude that despite what most of the tutorials out there say, shouldOverrideUrlLoading() does not get called when:
You load a URL like
loadUrl("http://www.google.com");
The browser redirects the user automatically via an HTTP Redirect. (See the comment from #hmac below regarding redirects)
It does however, get called when you you click on a link inside a webpage inside the webview. IIRC the twitter authorization uses an HTTP Redirect.. Bummer, this would be helpful if it worked how all the tutorials say it does. I think this is from a very old version the Android API...
You might want to consider overriding the onProgressChanged method of a WebChromeClient like here: How to listen for a WebView finishing loading a URL? or the onPageFinished() method of the WebViewClient.

I've found what I think is a reasonable way to do this thanks to the previous answer and comments pointing me in the right direction.
What I did is override onPageStarted and onPageFinished in a custom WebViewClient.
The code goes something like this...
#Override
public void onPageStarted(WebView view, String url, Bitmap favicon) {
if (pendingUrl == null) {
pendingUrl = url;
}
}
#Override
public void onPageFinished(WebView view, String url) {
if (!url.equals(pendingUrl)) {
Log.d(TAG, "Detected HTTP redirect " + pendingUrl + "->" + url);
pendingUrl = null;
}
}
And of course along with the Log.d you would put any specific code you want to run upon detecting the redirect.

For people stumbling across this, when the method shouldOverrideUrlLoading(WebView view, WebResourceRequest request) is not being called, look up your minSdkVersion. If you use below API 24 you should use shouldOverrideUrlLoading(WebView view, String url).