Volley.java 文件源码

private static HttpStack getDefaultStack(Context context){
    String userAgent = "volley/0";
    try {
        String packageName = context.getPackageName();

        PackageInfo info = context.getPackageManager().getPackageInfo(packageName, 0);
        userAgent = packageName + "/" + info.versionCode;
    } catch (NameNotFoundException e) {
    }

    if (Build.VERSION.SDK_INT >= 9) {
       return new HurlStack();
    } else {
        // Prior to Gingerbread, HttpUrlConnection was unreliable.
        // See: http://android-developers.blogspot.com/2011/09/androids-http-clients.html
        return new HttpClientStack(AndroidHttpClient.newInstance(userAgent));
    }       
}