private void _evaluateJavascript(String script) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            WVJBWebView.super.evaluateJavascript(script, null);
        } else {
            super.loadUrl("javascript:" + script);
        }
    }
set a listener for javascript closing the current activity.
app/src/main/java/com/example/jingbin/webviewstudy/view/WVJBWebView.java