Android Webview - Completely Clear the Cache

Question

I have a WebView in one of my Activities, and when it loads a webpage, the page gathers some background data from Facebook.

What I'm seeing though, is the page displayed in the application is the same on each time the app is opened and refreshed.

I've tried setting the WebView not to use cache and clear the cache and history of the WebView.

I've also followed the suggestion here: How to empty cache for WebView?

But none of this works, does anyone have any ideas of I can overcome this problem because it is a vital part of my application.

    mWebView.setWebChromeClient(new WebChromeClient()
    {
           public void onProgressChanged(WebView view, int progress)
           {
               if(progress >= 100)
               {
                   mProgressBar.setVisibility(ProgressBar.INVISIBLE);
               }
               else
               {
                   mProgressBar.setVisibility(ProgressBar.VISIBLE);
               }
           }
    });
    mWebView.setWebViewClient(new SignInFBWebViewClient(mUIHandler));
    mWebView.getSettings().setJavaScriptEnabled(true);
    mWebView.clearHistory();
    mWebView.clearFormData();
    mWebView.clearCache(true);

    WebSettings webSettings = mWebView.getSettings();
    webSettings.setCacheMode(WebSettings.LOAD_NO_CACHE);

    Time time = new Time();
    time.setToNow();

    mWebView.loadUrl(mSocialProxy.getSignInURL()+"?time="+time.format("%Y%m%d%H%M%S"));

So I implemented the first suggestion (Although changed the code to be recursive)

private void clearApplicationCache() {
    File dir = getCacheDir();

    if (dir != null && dir.isDirectory()) {
        try {
            ArrayList<File> stack = new ArrayList<File>();

            // Initialise the list
            File[] children = dir.listFiles();
            for (File child : children) {
                stack.add(child);
            }

            while (stack.size() > 0) {
                Log.v(TAG, LOG_START + "Clearing the stack - " + stack.size());
                File f = stack.get(stack.size() - 1);
                if (f.isDirectory() == true) {
                    boolean empty = f.delete();

                    if (empty == false) {
                        File[] files = f.listFiles();
                        if (files.length != 0) {
                            for (File tmp : files) {
                                stack.add(tmp);
                            }
                        }
                    } else {
                        stack.remove(stack.size() - 1);
                    }
                } else {
                    f.delete();
                    stack.remove(stack.size() - 1);
                }
            }
        } catch (Exception e) {
            Log.e(TAG, LOG_START + "Failed to clean the cache");
        }
    }
}

However this still hasn't changed what the page is displaying. On my desktop browser I am getting different html code to the web page produced in the WebView so I know the WebView must be caching somewhere.

On the IRC channel I was pointed to a fix to remove caching from a URL Connection but can't see how to apply it to a WebView yet.

http://www.androidsnippets.org/snippets/45/

If I delete my application and re-install it, I can get the webpage back up to date, i.e. a non-cached version. The main problem is the changes are made to links in the webpage, so the front end of the webpage is completely unchanged.

`mWebView.getSettings().setAppCacheEnabled(false);` did not worked ? — Paul, Feb 01 '12 at 08:49

score 233 · Answer 1 · edited Feb 19 '14 at 10:44

233

I found an even elegant and simple solution to clearing cache

WebView obj;
obj.clearCache(true);

http://developer.android.com/reference/android/webkit/WebView.html#clearCache%28boolean%29

I have been trying to figure out the way to clear the cache, but all we could do from the above mentioned methods was remove the local files, but it never clean the RAM.

The API clearCache, frees up the RAM used by the webview and hence mandates that the webpage be loaded again.

edited Feb 19 '14 at 10:44

Tamil Selvan C

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answered Mar 21 '12 at 08:02

Akshat

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The best answer and I wonder why its not accepted..Kudos Akshat :) – Karthik Sep 26 '14 at 11:49
3

No luck for me. Wonder if something has changed? I can load a WebView with google.com and the WebView still thinks I am logged in, even after clearCache(true); – lostintranslation Sep 02 '15 at 01:19
2

@lostintranslation For that you probably want to delete cookies. Though I'm sure you found that out by now. – NineToeNerd Mar 03 '16 at 03:42
Need to allocate the object? WebView obj= new WebView(this); obj.clearCache(true); Anyway, very good for me, upvoted! – Giorgio Barchiesi Nov 06 '19 at 07:03

score 50 · Accepted Answer · answered Oct 21 '10 at 09:27

The edited code snippet above posted by Gaunt Face contains an error in that if a directory fails to delete because one of its files cannot be deleted, the code will keep retrying in an infinite loop. I rewrote it to be truly recursive, and added a numDays parameter so you can control how old the files must be that are pruned:

//helper method for clearCache() , recursive
//returns number of deleted files
static int clearCacheFolder(final File dir, final int numDays) {

    int deletedFiles = 0;
    if (dir!= null && dir.isDirectory()) {
        try {
            for (File child:dir.listFiles()) {

                //first delete subdirectories recursively
                if (child.isDirectory()) {
                    deletedFiles += clearCacheFolder(child, numDays);
                }

                //then delete the files and subdirectories in this dir
                //only empty directories can be deleted, so subdirs have been done first
                if (child.lastModified() < new Date().getTime() - numDays * DateUtils.DAY_IN_MILLIS) {
                    if (child.delete()) {
                        deletedFiles++;
                    }
                }
            }
        }
        catch(Exception e) {
            Log.e(TAG, String.format("Failed to clean the cache, error %s", e.getMessage()));
        }
    }
    return deletedFiles;
}

/*
 * Delete the files older than numDays days from the application cache
 * 0 means all files.
 */
public static void clearCache(final Context context, final int numDays) {
    Log.i(TAG, String.format("Starting cache prune, deleting files older than %d days", numDays));
    int numDeletedFiles = clearCacheFolder(context.getCacheDir(), numDays);
    Log.i(TAG, String.format("Cache pruning completed, %d files deleted", numDeletedFiles));
}

Hopefully of use to other people :)

Can I use this code within an app to clear cache for certain app installed on my phone? — Si8, Oct 08 '13 at 21:25
If the whole directory needs to be deleted wouldn't Runtime.getRuntime().exec("rm -rf "+dirName+"\n"); be easier? — source.rar, Mar 09 '14 at 10:02
@source.rar Yes, but then you have no ability to keep files younger than x days old, which typically you want for a cache folder. — markjan, Sep 24 '14 at 12:28
You might want to put `getTime()` into a variable outside the loop so you don't call it everytime. — Fred, Oct 29 '15 at 19:38
Is it possible to use this code to only delete HTML files in the cache? — user4951834, Jan 06 '16 at 22:13

score 49 · Answer 3 · edited Apr 07 '16 at 13:30

49

I found the fix you were looking for:

context.deleteDatabase("webview.db");
context.deleteDatabase("webviewCache.db");

For some reason Android makes a bad cache of the url which it keeps returning by accident instead of the new data you need. Sure, you could just delete the entries from the DB but in my case I am only trying to access one URL so blowing away the whole DB is easier.

And don't worry, these DBs are just associated with your app so you aren't clearing the cache of the whole phone.

edited Apr 07 '16 at 13:30

Ziem

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answered Sep 13 '10 at 01:19

Scott

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Thanks, this is an incredibly neat trick. It deserves to be more widely known. – Philip Sheard May 21 '11 at 12:54
2

This throws a nasty exception in honeycomb: 06-14 22:33:34.349: ERROR/SQLiteDatabase(20382): Failed to open the database. closing it. 06-14 22:33:34.349: ERROR/SQLiteDatabase(20382): android.database.sqlite.SQLiteDiskIOException: disk I/O error 06-14 22:33:34.349: ERROR/SQLiteDatabase(20382): at android.database.sqlite.SQLiteDatabase.native_setLocale(Native Method) – Rafael Sanches Jun 14 '11 at 22:35
Cheers Rafael, I would like to think this is because the original issue has been resolved in Honeycomb. Does anyone know if this is the case? – Scott Jun 15 '11 at 00:21
just put 2 lines in onBackpress() or back button no history remain in back stack thanks saved lots of time. – CrazyMind Dec 21 '16 at 12:14
This does not seem to clear JS cache, only HTML.. is that the case? – Immanuel Oct 14 '22 at 17:11

score 41 · Answer 4 · edited Feb 03 '18 at 00:56

41

To clear all the webview caches while you signOUT form your APP:

CookieSyncManager.createInstance(this);         
CookieManager cookieManager = CookieManager.getInstance();        
cookieManager.removeAllCookie();

For Lollipop and above:

CookieSyncManager.createInstance(this);         
CookieManager cookieManager = CookieManager.getInstance();        
cookieManager.removeAllCookies(ValueCallback);

edited Feb 03 '18 at 00:56

Kingston

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answered Jun 05 '14 at 06:37

amalBit

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1

save my life and day. – Uday Nayak Aug 22 '16 at 05:47
2

Works fine if you don't have access to webview in your activity. Also note that this API has been deprecated,so use the "removeAllCookies(ValueCallback)" API instead on L+ devices. – Akshat Feb 11 '17 at 03:35
what should I replace with ValueCallBack? – Qaiser Hussain Mar 16 '20 at 08:19
@QaisarKhanBangash new ValueCallback() { atOverride public void onReceiveValue(Boolean value) { } } – amalBit Mar 16 '20 at 10:46

score 25 · Answer 5 · answered Jan 28 '20 at 10:38

To clear cookie and cache from Webview,

    // Clear all the Application Cache, Web SQL Database and the HTML5 Web Storage
    WebStorage.getInstance().deleteAllData();

    // Clear all the cookies
    CookieManager.getInstance().removeAllCookies(null);
    CookieManager.getInstance().flush();

    webView.clearCache(true);
    webView.clearFormData();
    webView.clearHistory();
    webView.clearSslPreferences();

score 6 · Answer 6 · answered Jan 27 '20 at 12:07

6

The only solution that works for me

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP_MR1) {
    CookieManager.getInstance().removeAllCookies(null);
    CookieManager.getInstance().flush();
}

answered Jan 27 '20 at 12:07

Ketan Ramani

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score 3 · Answer 7 · edited Apr 07 '16 at 13:32

3

This should clear your applications cache which should be where your webview cache is

File dir = getActivity().getCacheDir();

if (dir != null && dir.isDirectory()) {
    try {
        File[] children = dir.listFiles();
        if (children.length > 0) {
            for (int i = 0; i < children.length; i++) {
                File[] temp = children[i].listFiles();
                for (int x = 0; x < temp.length; x++) {
                    temp[x].delete();
                }
            }
        }
    } catch (Exception e) {
        Log.e("Cache", "failed cache clean");
    }
}

edited Apr 07 '16 at 13:32

Ziem

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answered Mar 17 '10 at 20:41

jqpubliq

11,874
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Tried this (Changed code slightly) and still got the same results -> Explained above – Matt Gaunt Mar 17 '10 at 21:14

score 3 · Answer 8 · answered Dec 12 '20 at 20:02

webView.clearCache(true)
appFormWebView.clearFormData()
appFormWebView.clearHistory()
appFormWebView.clearSslPreferences()
CookieManager.getInstance().removeAllCookies(null)
CookieManager.getInstance().flush()
WebStorage.getInstance().deleteAllData()

score 2 · Answer 9 · answered Dec 07 '19 at 13:29

2

Simply using below code in Kotlin works for me

WebView(applicationContext).clearCache(true)

answered Dec 07 '19 at 13:29

Ercan

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score 1 · Answer 10 · answered Dec 14 '18 at 12:10

1

CookieSyncManager.createInstance(this);         
CookieManager cookieManager = CookieManager.getInstance();        
cookieManager.removeAllCookie();

answered Dec 14 '18 at 12:10

WaqasArshad

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score 1 · Answer 11 · answered Jan 06 '19 at 02:12

1

CookieSyncManager.createInstance(this);    
CookieManager cookieManager = CookieManager.getInstance(); 
cookieManager.removeAllCookie();

It can clear google account in my webview

answered Jan 06 '19 at 02:12

Dũng Phạm Tiến

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CookieSyncManager is depricated – NoWar Apr 01 '19 at 03:57

score 1 · Answer 12 · answered Dec 28 '22 at 20:53

1

Previous code has been deprecated. So, you can try this one in Kotlin base android projects:

CookieManager.getInstance().removeAllCookies {  
   // Do your work here.
}

answered Dec 28 '22 at 20:53

canerkaseler

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I use this method to solve my problem. I see many answers containing "CookieManager.getInstance().flush()". It is not needed, because flush() write cookie to database in fact. If you want to clear all db, you can try WebStorage.getInstance().deleteAllData(); but in most cases it is not needed – JeckOnly Apr 27 '23 at 02:07

score 0 · Answer 13 · edited Mar 18 '14 at 11:51

0

Make sure you use below method for the form data not be displayed as autopop when clicked on input fields.

getSettings().setSaveFormData(false);

edited Mar 18 '14 at 11:51

Aduait Pokhriyal

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answered Dec 27 '12 at 22:51

Raghu

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score 0 · Answer 14 · edited Mar 18 '14 at 11:51

0

To clear the history, simply do:

this.appView.clearHistory();

Source: http://developer.android.com/reference/android/webkit/WebView.html

edited Mar 18 '14 at 11:51

Aduait Pokhriyal

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answered Feb 24 '14 at 21:35

Alan CN

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score 0 · Answer 15 · edited Jan 06 '21 at 02:18

0

context.deleteDatabase("webview.db");
context.deleteDatabase("webviewCache.db")

Did the trick

edited Jan 06 '21 at 02:18

Joundill

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answered Jan 05 '21 at 22:00

Terre

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score 0 · Answer 16 · answered Oct 05 '21 at 11:59

0

to completely clear the cache in kotlin you can use:

context.cacheDir.deleteRecursively()

Just in case someone needs the kotlin code (:

answered Oct 05 '21 at 11:59

Iskandir

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Android Webview - Completely Clear the Cache

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