didimoo / androidlocalstorage

How to implement correctly a LocalStorage feature in Android Webview

AndroidLocalStorage

LocalStorage is partially broken in Android webviews : Local storage is supposed to be a persistent storage available accros all tabs (or windows) of a browser. On Android, LocalStorage works well but only in the current webview. Multiple webviews of the same app can't share the same data with LocalStorage. That is sad !

JavaScriptInterface to the rescue !

This sample Android app shows you how you can fix the webview LocalStorage with a JavaScriptInterface.

What we do here is :

• Create an Android database with a simple key/value table
• Create a JavaScriptInterface which implements all LocalStorage's methods (getItem, setItem, removeItem, clear)
• Add it to the webview
• Replace the JavaScript LocalStorage with this "new one" so that you don't have to change the way you use your localStorage usually.

How to use it in your own project ?

• Include the LocalStorage.java
• Create the JavaScriptInterface and add it to the webview as shown in MainFragment.java
• Bind the JavaScript LocalStorage to the new one as shown in assets/index.html

This last step is as simple as this :

<script type="text/javascript">
        try{
            //we replace default localStorage with our Android Database one
            window.localStorage=LocalStorage;    
        }catch(e){
            //LocalStorage class was not found. be sure to add it to the webview
		         	alert("LocalStorage ERROR : can't find android class LocalStorage. switching to raw localStorage")		        
		      }
    //then use your localStorage as usual
    localStorage.setItem('foo','it works')
    alert(localStorage.getItem('foo'))
    
</script>

Play with this example project to see how it works.

androidlocalstorage's Issues

The Given JS interface is NOT working.

Please refer to the following stackoverflow page where I have posted details about the issue I am facing.

http://stackoverflow.com/questions/21298664/javascript-interface-not-working-in-my-android-application

Issue: The LocalStorage is NOT working for me. I tried adding some items in LocalStorage but when I am closing the application and opening again those items from Localstorage are getting wiped out.

java database Not call by javascript

it seems that this project does not work,it still use webview localstorage.
I try to debug it but java interface function does not call !!!
when change "l" to "L" they have been called, but javascript could not recognize function answer

Two activities Problem

I try to add a new activity that named SecondActivity.I change "Open a new webview" btn jump to SecondActivity. Then I save a key-value like "mykey-mynewValue" in SecondActivity,but when I get back MainActivity the key-value can't read,its value still is "myValue".

And I try to debug LocalStorageJavaScriptInterface,but it doesn't break in it?

Can you help me?Thanh you.