title: android: call javascript from java problem
body: <p>I want to know if there is way to call javascript from java on android?
  In my program, I interact java and javascript together. I am using java to receive response(json data) from TCP server and save them into a file. In webview I am using javascript jQuery getJSON() function to retrieve that file and using jQuery plot chart library to draw chart. Now, there is no relationship between java and javascript. Every time when I update data and file, I still need to click a button in webview to trigger the draw function. I want the programmes to be smart and handy. Is that a way to call or execute javascript from java. I know one way:</p>
  
  <pre><code>Button update = (Button)findViewById(R.id.update);
          update.setOnClickListener(new View.OnClickListener() {
  
              @Override
              public void onClick(View v) {
                  // TODO Auto-generated method stub
                  wv.loadUrl("javascript:document.write('hello')");
              }
          });
  </code></pre>
  
  <p>But the problem is I already do a index page by loadurl().</p>
  
  <pre><code>final WebView wv = (WebView) findViewById(R.id.webkankan);
          wv.getSettings().setJavaScriptEnabled(true);
          wv.loadUrl("file:///android_asset/index.html");
  </code></pre>
  
  <p>When I trigger this click event, all contents were gone only a string "hello" there. Another thing is why I need to change webview's type to final to avoid eclipse error. Does this is the problem to trigger my main problem? If so, how can I fix it?
  Thanks for you patience. 
  Cheers!</p>