我写了一个webview调用android方法，这个回调方法可以更新UI，但是这个方法不是UI线程，为什么呢？谢谢！

test.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Test HTML</title>
</head>
<body>
    <button onclick="callNativeMethod()">Call Android Method</button>
    <script>
        function callNativeMethod(){
            window.android.toast("invock android method")
        }
    </script>
</body>

</html>

android

webView.loadUrl("file:///android_asset/test.html");
webView.addJavascriptInterface(new JSBridge(), "android");

JSBridge

class JSBridge {
        @JavascriptInterface
        public void toast(String msg) {
            Log.e(TAG, "toast: " + Thread.currentThread().getName());
            Log.e(TAG, "toast: " + (Looper.getMainLooper() == Looper.myLooper()));
            textView.setText(msg);
            Toast.makeText(WebViewActivity.this, msg, Toast.LENGTH_SHORT).show();
        }
    }

LOG

12-10 10:35:50.194 21207-21275/lsl.test.cheyixiaotest E/WebViewActivity: toast: JavaBridge
    toast: false
android webview