[Android]WebView method must on same thread

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_layout);
        final WebView webView = (WebView)findViewById(R.id.webView);
        webView.getSettings().setJavaScriptEnabled(true);
        webView.setWebChromeClient(new WebChromeClient());
        WebSettings webSettings = webView.getSettings();
        webSettings.setJavaScriptEnabled(true);

        javascr = new AndroidJavascript(this, webView);
        webView.addJavascriptInterface(javascr, "AndroidFunction");
        webView.loadUrl("file:///android_asset/www/index.html");
}

public class AndroidJavascript {   
    Context cont;
    WebView webView;

    AndroidJavascript(Context c, WebView w) {
        cont = c;
        webView = w;
    }

    // function called in the javascript by AndroidFunction.test();
    public void test() {
        webView.loadUrl("javascript:helloBack()");
    }
}

问题解决

    public void test() {
        webView.post(new Runnable() {
            public void run() {
                webView.loadUrl("javascript:helloBack()");
            }
        });
    }