凌空onErrorResponse给NullPointerException异常 [英] Volley onErrorResponse Give NullPointerException

问题描述

我尝试凌空库在我的Andr​​oid应用程序

i try volley library in my android application

这是我的日志

    10-31 14:30:09.277: E/AndroidRuntime(22916): java.lang.NullPointerException
10-31 14:30:09.277: E/AndroidRuntime(22916):    at com.mypackage.api.Api$2.onErrorResponse(Api.java:269)
10-31 14:30:09.277: E/AndroidRuntime(22916):    at com.android.volley.Request.deliverError(Request.java:517)
10-31 14:30:09.277: E/AndroidRuntime(22916):    at com.android.volley.ExecutorDelivery$ResponseDeliveryRunnable.run(ExecutorDelivery.java:101)
10-31 14:30:09.277: E/AndroidRuntime(22916):    at android.os.Handler.handleCallback(Handler.java:615)
10-31 14:30:09.277: E/AndroidRuntime(22916):    at android.os.Handler.dispatchMessage(Handler.java:92)
10-31 14:30:09.277: E/AndroidRuntime(22916):    at android.os.Looper.loop(Looper.java:137)
10-31 14:30:09.277: E/AndroidRuntime(22916):    at android.app.ActivityThread.main(ActivityThread.java:4745)
10-31 14:30:09.277: E/AndroidRuntime(22916):    at java.lang.reflect.Method.invokeNative(Native Method)
10-31 14:30:09.277: E/AndroidRuntime(22916):    at java.lang.reflect.Method.invoke(Method.java:511)
10-31 14:30:09.277: E/AndroidRuntime(22916):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
10-31 14:30:09.277: E/AndroidRuntime(22916):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
10-31 14:30:09.277: E/AndroidRuntime(22916):    at dalvik.system.NativeStart.main(Native Method)

这是我如何使用凌空

    GetStringRequest req = new GetStringRequest(Request.Method.GET,URL_API,
    new Response.Listener<String>() {
    // handle success response
    }, new Response.ErrorListener() {
    //handle error response
    @Override
public void onErrorResponse(VolleyError volleyError) {

    try {
        String error = new String(volleyError.networkResponse.data, HTTP.UTF_8);
        }
        catch (UnsupportedEncodingException e) {
            // TODO Auto-generated catch block
        e.printStackTrace();
        }
    });

有时候，我在这行得到错误NullPointerException异常（269）

sometimes i get error nullPointerException at this line (269)

String error = new String(volleyError.networkResponse.data, HTTP.UTF_8);

我不知道什么是错的，任何人都知道吗？

i don't know what is wrong, anyone know?

推荐答案

有机会，volleyError.networkResponse.data是空的。我不知道你正在试图让这条线code，但随着乱射工作，想看看是什么volleyError。你可以试试这个：

Chances are that volleyError.networkResponse.data is empty. I am not sure what you are trying to get with this line of code, but working with Volley and wanting to see what is in volleyError. You could try this:

String error =  volleyError.toString();

您可以检查此字符串任何特定错误[至少这是我要做的事。 VolleyErrors可以由API定义的为数不多的诸如超时错误，连接错误，服务器错误，等等。的 - 当然，你可能不得不进一步解析字符串，如果你想火基于一个特定的错误的其他行动。

You can then check this string for any specific errors [at least that's how I do it]. VolleyErrors could be one of the few defined by the API such as timeout error, connection error, server error, and so forth. Of-course, you might have to parse the string further if you want to fire other actions based on a specific error.

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