Android Webview-캐시 완전 삭제

Android Webview-캐시 완전 삭제

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내 활동 중 하나에 WebView가 있고 웹 페이지를로드 할 때 페이지가 Facebook에서 배경 데이터를 수집합니다.

그래도 내가 보는 것은 응용 프로그램에 표시된 페이지가 앱을 열고 새로 고칠 때마다 동일하다는 것입니다.

캐시를 사용하지 않고 WebView의 캐시 및 기록을 지우도록 WebView를 설정하려고 시도했습니다.

또한 여기 제안을 따랐습니다. WebView의 캐시를 비우는 방법?

그러나이 중 어느 것도 작동하지 않습니다.이 문제는 내 응용 프로그램의 중요한 부분이기 때문에이 문제를 극복 할 수 있다는 생각이있는 사람은 없습니다.

    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"));

그래서 첫 번째 제안을 구현했습니다 (코드를 재귀 적으로 변경했지만)

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.

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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 :)

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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.

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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.

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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);

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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");
    }
}

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To clear the history, simply do:

this.appView.clearHistory();

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

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

getSettings().setSaveFormData(false);

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

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

It can clear google account in my webview

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use case: list of item are displaying in recycler view, whenever any item click it hides recycler view and shows web view with item url.

problem: i have similar problem in which once i open a url_one in webview , then try to open another url_two in webview, it shows url_one in background till url_two is loaded.

solution: so to solve what i did is load blank string "" as url just before hiding url_one and loading url_two.

output: whenever i load any new url in webview it does not show any other web page in background.

code

public void showWebView(String url){
        webView.loadUrl(url);
        recyclerView.setVisibility(View.GONE);
        webView.setVisibility(View.VISIBLE);
    }

public void onListItemClick(String url){
   showWebView(url);
}

public void hideWebView(){
        // loading blank url so it overrides last open url
        webView.loadUrl("");
        webView.setVisibility(View.GONE);
        recyclerView.setVisibility(View.GONE);
   }


 @Override
public void onBackPressed() {
    if(webView.getVisibility() == View.VISIBLE){
        hideWebView();
    }else{
        super.onBackPressed();
    }
}

참고URL : https://stackoverflow.com/questions/2465432/android-webview-completely-clear-the-cache