How to add notifications, when there is any change in WebView App? - android

How to add notifications to WebView App when there is any changes in the web url. i.e. if user creates a new task in webview then I need to notify user.

Implement WebViewClient and extend onPageFinished() , so you can even see url:
mWebView.setWebViewClient(new WebViewClient() {
public void onPageFinished(WebView view, String url) {
// do your stuff here
}
});

Related

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...

How to restore default WebViewClient in WebView

Is there any way to restore a default WebViewClient in WebView?
There is a WebView.setWebViewClient(WebViewClient client) method, but no get companion.
I would like to to load URL in WebView and avoid being sent to native browser in case of redirections but then go back to default behavior - links clicked opening in native browser.
To achieve that I would like set my own WebViewClient temporarily and then restore the default one.
WebView webView = new WebView(this);
webView.setWebViewClient(new WebViewClient());
webView.loadUrl("http://example.com");
// TODO: restore default WebViewClient
to go back to the default behavior try:
webview.setWebViewClient(null);
however you can't do that immediately after you call loadUrl, you need to at least wait for WebViewClient.onPageFinished.
Finally the code:
webView.setWebViewClient(new WebViewClient() {
#Override
public void onPageFinished(WebView view, String url) {
webView.setWebViewClient(null);
}
});
webView.loadUrl(url);

Android WebView navigation

I want to add news and weather app in webview. But jumping to anyther website from webview is not an option. How can I restrict a webview for a certain website.
Thanks.
Create your own WebViewClient:
public class CustomWebViewClient extends WebViewClient {
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
if(url.getHost().equals("weather.com")){
// load link
return false;
}else{
// block link
return true;
}
}
}
Use it like this:
webview.setWebViewClient(new CustomWebViewClient());
EDIT Note:
an example of a getHost() function
If I understand the question correctly you might want to implement your own WebViewClient. That will allow you to handle the page navigation. Check out the link for a tutorial from Google.
viewer.setWebViewClient(new WebViewClient(){
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
//Block all URL accesses.
return false;
}
});
That should prevent access to anything. You need to handle specific URL's in this function if you want to allow them.

Android WebView - Intercept clicks

I have written a simple helloworld app with a WebView which has a link to CNN on a simple.html page in my asset folder.
cnn.com
How can I capture the click on this on my Activity, stop the WebView from navigating, and then inform the Activity that "http://CNN.com" was clicked?
Then you have to set a WebViewClient to your WebView and override shouldOverrideUrlLoading and onLoadResource methods. Let me give you a simple example:
WebView yourWebView; // initialize it as always...
// this is the funny part:
yourWebView.setWebViewClient(yourWebClient);
// somewhere on your code...
WebViewClient yourWebClient = new WebViewClient(){
// you tell the webclient you want to catch when a url is about to load
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url){
return true;
}
// here you execute an action when the URL you want is about to load
#Override
public void onLoadResource(WebView view, String url){
if( url.equals("http://cnn.com") ){
// do whatever you want
}
}
}

Clicking URLs opens default browser

I have loaded an external URL in my WebView. Now what I need is that when the user clicks on the links on the page loaded, it has to work like a normal browser and open the link in the same WebView. But it's opening the default browser and loading the page there?
I have enabled JavaScript. But still it's not working. Have I forgotten something?
If you're using a WebView you'll have to intercept the clicks yourself if you don't want the default Android behaviour.
You can monitor events in a WebView using a WebViewClient. The method you want is shouldOverrideUrlLoading(). This allows you to perform your own action when a particular URL is selected.
You set the WebViewClient of your WebView using the setWebViewClient() method.
If you look at the WebView sample in the SDK there's an example which does just what you want. It's as simple as:
private class HelloWebViewClient extends WebViewClient {
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
view.loadUrl(url);
return true;
}
}
in some cases you might need an override of onLoadResource if you get a redirect which doesn't trigger the url loading method. in this case i tried the following:
#Override
public void onLoadResource(WebView view, String url)
{
if (url.equals("http://redirectexample.com"))
{
//do your own thing here
}
else
{
super.onLoadResource(view, url);
}
}
Official documentation says, click on a link in a WebView will launch application that handles URLs. You need to override this default behavior
myWebView.setWebViewClient(new WebViewClient() {
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
return false;
}
});
or if there is no conditional logic in the method simply do this
myWebView.setWebViewClient(new WebViewClient());
Add this 2 lines in your code -
mWebView.setWebChromeClient(new WebChromeClient());
mWebView.setWebViewClient(new WebViewClient());
The method boolean shouldOverrideUrlLoading(WebView view, String url) was deprecated in API 24. If you are supporting new devices you should use boolean shouldOverrideUrlLoading (WebView view, WebResourceRequest request).
You can use both by doing something like this:
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
newsItem.setWebViewClient(new WebViewClient() {
#Override
public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
view.loadUrl(request.getUrl().toString());
return true;
}
});
} else {
newsItem.setWebViewClient(new WebViewClient() {
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url) {
view.loadUrl(url);
return true;
}
});
}
Arulx Z's answer was exactly what I was looking for.
I'm writing an app with Navigation Drawer with recyclerview and webviews, for keeping the web browsing inside the app regardless of hyperlinks clicked (thus not launching the external web browser). For that it will suffice to put the following 2 lines of code:
mWebView.setWebChromeClient(new WebChromeClient());
mWebView.setWebViewClient(new WebViewClient());
exactly under your WebView statement.
Here's a example of my implemented WebView code:
public class WebView1 extends AppCompatActivity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
WebView wv = (WebView) findViewById(R.id.wv1); //webview statement
wv.setWebViewClient(new WebViewClient()); //the lines of code added
wv.setWebChromeClient(new WebChromeClient()); //same as above
wv.loadUrl("http://www.google.com");
}}
this way, every link clicked in the website will load inside your WebView.
(Using Android Studio 1.2.2 with all SDK's updated)

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