Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
240 views
in Technique[技术] by (71.8m points)

java - Android webview cookie returns null

I'm trying to simply set and retrieve a cookie inside a webview in android. I have tried numerous cookie manager scripts to try and get this to work. I have JavaScript enabled.

When running the application on a Samsung S3 and a Samsung Galaxy Tab 10.1 cookies don't appear to set at all (android 4.1). However, when running the software on a Samsung Galaxy ace, HTC Desire Z and in the android emulators, the cookies are set and read perfectly fine.

When working, the webview returns the string as expected, when not working, the output is simply "null"; the cookie has not value/is not set.

My specific case also uses sliding Navigation class, which is an extension of Actionbar Sherlock.

I'd really appreciate any help, I've been struggling with this for several weeks now. Thank you.

HTML:

<html>
<head>
    <title>
    </title>
<script>
    function createCookie(name, value) 
    {
            var day  = (1 * 24 * 60 * 60 * 1000);
            var date = new Date();
            date.setTime(date.getTime() + (20 * 365 * day));
            var expires = "; expires=" + date.toGMTString();

            document.cookie = name + '=; expires=Thu, 01 Jan 1970 00:00:01 GMT;';
            document.cookie = name + "=" + value + expires + "; path=/";
    }

    function readCookie(name) 
    {
        var nameEQ = name + "=";
        var ca = document.cookie.split(';');
        for(var i=0;i < ca.length;i++) {
            var c = ca[i];
            while (c.charAt(0)==' ') c = c.substring(1,c.length);
            if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
        }
        return null;
    }

</script>
</head>
<body>
<h1 class="">
<script type="text/javascript">
    createCookie("test", "If this is working, it returns this string. If this is not working, it returns null.");
    document.write("test: " + readCookie("test"));
</script>
</body>
</html>

Java Code:

public class MainActivity extends SherlockActivity implements ISideNavigationCallback {

public static final String EXTRA_TITLE = "com.devspark.sidenavigation.sample.extra.MTGOBJECT";
public static final String EXTRA_RESOURCE_ID = "com.devspark.sidenavigation.sample.extra.RESOURCE_ID";
public static final String EXTRA_MODE = "com.devspark.sidenavigation.sample.extra.MODE";
public static String WebLoaded = "0";
public static String page = "signup.php";

private ImageView icon;
private SideNavigationView sideNavigationView;
private WebView engine;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);

    icon = (ImageView) findViewById(android.R.id.icon);
    sideNavigationView = (SideNavigationView) findViewById(R.id.side_navigation_view);
    sideNavigationView.setMenuItems(R.menu.side_navigation_menu);
    sideNavigationView.setMenuClickCallback(this);

    if (getIntent().hasExtra(EXTRA_TITLE)) {
        String title = getIntent().getStringExtra(EXTRA_TITLE);
        int resId = getIntent().getIntExtra(EXTRA_RESOURCE_ID, 0);
        setTitle(title);
        icon.setImageResource(resId);
        sideNavigationView.setMode(getIntent().getIntExtra(EXTRA_MODE, 0) == 0 ? Mode.LEFT : Mode.RIGHT);
    }

   //test
    getSupportActionBar().setDisplayHomeAsUpEnabled(true);

    String domain = "localhost";

    CookieManager cookieManager = CookieManager.getInstance();
    cookieManager.setAcceptCookie(true);
    cookieManager.setCookie(domain, "name=value");
    cookieManager.setCookie(domain, "path=/");
    cookieManager.setCookie(domain, "HttpOnly");

    //enable cookies
    CookieManager.getInstance().setAcceptCookie(true);
    //navigates web engine, including on nav click
    engine = (WebView) findViewById(R.id.web_engine);  


    engine.loadUrl("file:///android_asset/" + page);
    //enable JavaScript support - disabled by default for some weird reason
    engine.getSettings().setJavaScriptEnabled(true);  
    engine.setWebViewClient(new WebViewClient());        






    //disables text selection
    engine.setOnLongClickListener(new View.OnLongClickListener() {
        public boolean onLongClick(View v) {
            return true;
        }
    });     
}

@Override
public void onPause()
{
    super.onPause();
    engine.getSettings().setJavaScriptEnabled(false);
}

@Override
public void onResume()
{
    super.onResume();
    engine.getSettings().setJavaScriptEnabled(true);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case android.R.id.home:
            sideNavigationView.toggleMenu();
            break;
        case R.id.mode_left:
            item.setChecked(true);
            sideNavigationView.setMode(Mode.LEFT);
            break;
        case R.id.mode_right:
            item.setChecked(true);
            sideNavigationView.setMode(Mode.RIGHT);
            break;

        default:
            return super.onOptionsItemSelected(item);
    }
    return true;
}

@Override
public void onSideNavigationItemClick(int itemId) {


    switch (itemId) {
        case R.id.side_navigation_menu_item1:
            invokeActivity(getString(R.string.title1), R.drawable.ic_android1);     
            page = "index.html";
            break;

        case R.id.side_navigation_menu_item2:
            invokeActivity(getString(R.string.title2), R.drawable.ic_android2);
            page = "test.html";
            break;

        case R.id.side_navigation_menu_item3:
            invokeActivity(getString(R.string.title3), R.drawable.ic_android3);
            break;

        case R.id.side_navigation_menu_item4:
            invokeActivity(getString(R.string.title4), R.drawable.ic_android4);
            break;

        case R.id.side_navigation_menu_item5:
            invokeActivity(getString(R.string.title5), R.drawable.ic_android5);
            break;

        default:
            return;
    }
    finish();
}
See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Answer

0 votes
by (71.8m points)

After over a month of research I've concluded that setting a cookie in android versions greater than 2.3 is not possible in a webview where the file is on the localhost (read directly from the assets folder).

I went through many alternatives to to using cookie storage, including using HTML's localstorage. The whole issue here, I am led to believe, is security. If I were to create a cookie or localstorage on the localhost, then other apps could access that storage, thus is a major security threat.

My ultimate problem was trying to bridge the webview with two-way communication with java and also having a place to store data during the process. My solution was to take advantage of the JavascriptInterface

The idea is as follows:

  • Parse data to function in javascript
  • Javascript calls a special javascript function e.g. "setData(myDataName, myData)"
  • Java has a function which listens to this, and will take arguments set by javscript, and can also return values to javascript.
  • Once data is parsed to Java, java stores this in a series of files in assets.
  • When javascript function "getData(myDataName)" is called, the data is returned by the same kind of method by Java.

I found this very useful: Android JavascriptInterface Documentation, Handling JavascriptInterface in Android 2.3

The only major 'hang-ups' come with a what I found was a fairly serious bug in Android 2.3 (fixed in 3.0) which effectively broke the JavascriptInterface. The second link above describes the best workaround I have found.

Here is an example of how to get the two-way communication working (it's very messy, but it works):

Custom webinterface class:

public class webViewInterface { 
    //@JavascriptInterface //for SDK 12+
    public String showToast(String myText) {
        Toast.makeText(context, myText, Toast.LENGTH_LONG).show();
        return myText;
    }
    }

Main class: protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

engine = (WebView) findViewById(R.id.web_engine); 

context = this;
WebSettings webSettings = engine.getSettings();
webSettings.setJavaScriptEnabled(true);

engine.setWebViewClient(new WebViewClient());
engine.loadUrl("file:///android_asset/" + page);

boolean javascriptInterfaceBroken = false;
try {
        if (Build.VERSION.RELEASE.startsWith("2.3")) {
         javascriptInterfaceBroken = true;
        }
    } catch (Exception e) {

    // Ignore, and assume user javascript interface is working correctly.
    }

// Add javascript interface only if it's not broken
    // @TODO: write the workaround for < 2.3 devices
if (!javascriptInterfaceBroken) {
        engine.addJavascriptInterface(new webViewInterface(), "MainActivityInterface");
}   

//disables text selection
engine.setOnLongClickListener(new View.OnLongClickListener() {
    public boolean onLongClick(View v) {
        return true;
    }
});     
}

HTML:

<html>
<head>
</head>
<body>

<input type="button" value="Say hello" onClick="showAndroidToast();" />

<script type="text/javascript">
    function showAndroidToast() {
        document.write(MainActivityInterface.showToast("eureka!"));
    }
</script>

</body>
</html>

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...