Loading Non cached webview in android app - android

I have a HTML template file which is used at multiple places one of them is it is used to get loaded as a webview in few android apps, How can I make sure everytime webview is loaded it loads the most recent version(No cache) without making any changes in app settings.

You can try something like this:
WebView webview = new WebView(this);
webview.getSettings().setCacheMode(WebSettings.LOAD_NO_CACHE);
Check out more here

When WebView finishes a page everytime, clear the cache. Something like this in your WebViewClient:
#Override
public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
view.clearCache(true);
}

Just after creating your WebView, before loading any pages, you can clear the cache.
browser.clearCache(true);
and one other way is to Override onPageFinished() which is called each time a page gets loaded, so you could clear cache in it.
#Override
public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
view.clearCache(true);
}

Related

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

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
}
});

Run code only once after an application is opened android webview

I want to run code only once after an application is opened. I try onpagefinished but when I refresh page the code run again. Sorry for my bad English. This is my code.
#Override
public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
my code
}

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...

WebView doesn't show content after onPause

I have a WebView inside a RecyclerView
I configured the WebViewClient to run onPuase() when page finished loading.
The problem is that some websites (like IMDB) are not viewed, unless I scroll the page down/up, or if the page in stored in cache.
Not working code:
getWebview().setWebViewClient(new WebViewClient() {
#Override
public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
view.onPause();
}
});
If I delay the onPause, it works (delay time differs between different devices)
getWebview().setWebViewClient(new WebViewClient() {
#Override
public void onPageFinished(final WebView view, String url) {
super.onPageFinished(view, url);
getWebview().postDelayed(new Runnable() {
#Override
public void run() {
getWebview().onPause();
}
}, 5000);
}
});
I also tried getWebview().postInvalidateDelayed() and getWebview().requestLayout().
Is there anyway to force the webview to display the loaded content, or simulate whatever happens when I scroll the page?
I use Lollipop with Android System WebView 43.0.2357.121
If you try to debug or put some logs in onPagefinshed() method, you will come to know that Webview's onPauuse() will call 2-3 times before site the
loads completely in case of URL redirecting.

How to make a WebView visible only after it finished displaying content?

I have a webView, where I display a HTML I fetch from the backend.My problem is that I am trying to display a loading message, and show the content only after the page is done.
For doing that, I tried to use onPageFinished, which winda works, but not entirely, because it is called after the data is fetched, but BEFORE the page is displayed, so I'm still displaying a blank screen for about 1 second, before finally displaying the HTML.
From the oficial docs:
public void onPageFinished (WebView view, String url)
Added in API level 1
Notify the host application that a page has finished loading. This method is called only for main frame. When onPageFinished() is called, the rendering picture may not be updated yet. To get the notification for the new Picture, use onNewPicture(WebView, Picture).
The problem is that onNewPicture(WebView, Picture) is deprecated
So my question is, is there a way to know when the page is finished, but also fully displayed?
Here is my code:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.messageId = this.getIntent().getStringExtra(ITEM_ID_KEY);
this.setUpActionBar();
this.setContentView(R.layout.activity_inbox_item_detail);
WebView view = (WebView) this.findViewById(R.id.webview);
view.setWebViewClient(new WebViewClient() {
public void onPageFinished(WebView view, String url) {
view.setVisibility(View.VISIBLE);
}
});
this.fetchInboxDetailsTask(this.messageId);
}
I have a WebView in a fragment and, just for your reference, I have set it up like this.
May be you are missing something. "onPageFinished" works just fine for me.
In onViewCreated method:
mWebView = (WebView) view.findViewById(R.id.appWebView);
mWebView.setWebViewClient(new WebViewClient()
{
#Override
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl)
{
// Handle the error
}
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url)
{
view.loadUrl(url);
return true;
}
#Override
public void onPageFinished(WebView view, String url)
{
webViewProgressBar.setVisibility(View.GONE);
super.onPageFinished(view, url);
}
});
and then:
mWebView.getSettings().setJavaScriptEnabled(true);
mWebView.getSettings().setDomStorageEnabled(true);
mWebView.getSettings().setSupportZoom(true);
mWebView.getSettings().setBuiltInZoomControls(true);
mWebView.loadUrl("http://play.google.com/store/apps/");
You may consider using the Advanced Webview Library for android it provides an interface to reaspond to when page start loading and when finishes! here (AdvancedWebView)

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