请问android signalA 框架 断开网络 程序直接停止运行 要怎么改呢

protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 beginConnect();
 }
 /* *
 * hub链接
 */
 private HubConnection conn=new HubConnection(HUB, this, new LongPollingTransport()) {
 @Override
 public void OnError(Exception exception) {
 String a = "";
 }
 @Override
 public void OnMessage(String message) {
 String a = "";
 }
 @Override
 public void OnStateChanged(StateBase oldState, StateBase newState) {
 switch (newState.getState()){
 case Connected:JSONArray jsonArray = new JSONArray();
 jsonArray.put("b7f6ae28eaf44ef481929a6633fc34d2");
 hub.Invoke("externalLogin", jsonArray, new HubInvokeCallback() {
 @Override
 public void OnResult(boolean succeeded, String response) {
 Toast.makeText(MainActivity.this, response, Toast.LENGTH_LONG).show();
 }
                    @Override
                    public void OnError(Exception ex) {
                        Toast.makeText(MainActivity.this, ex.toString(), Toast.LENGTH_LONG).show();
                    }
                });
            break;
            case Connecting:String a = "";
                break;
            case Reconnecting: String a1 ="";break;
            case Disconnected: String a2  ="";break;
            case Disconnecting: String a3 = "";break;
        }
    }
};

     private void beginConnect(){
    try {
        hub=conn.CreateHubProxy("ChatHub");
    } catch (OperationApplicationException e) {
        e.printStackTrace();
    }
    hub.On("LoginCallback", new HubOnDataCallback() {
        @Override
        public void OnReceived(JSONArray args) {
            EditText chatText = (EditText) findViewById(R.id.edit);
            Toast.makeText(MainActivity.this, args.toString(), Toast.LENGTH_LONG).show();
            //chatText.setText(args.toString());
            for (int i = 0; i < args.length(); i++) {
                chatText.append(args.opt(i).toString());
            }
        }
    });

    conn.Start();
}

报的错误

12-11 14:01:09.602  25809-25809/com.example.fenghao.test W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x27fdad88)


12-11 14:01:09.602 25809-25809/com.example.test E/AndroidRuntime﹕ FATAL EXCEPTION: main
 Process: com.example.test, PID: 25809
 java.lang.NullPointerException
 at org.json.JSONTokener.nextCleanInternal(JSONTokener.java:116)
 at org.json.JSONTokener.nextValue(JSONTokener.java:94)
 at org.json.JSONObject.(JSONObject.java:155)
 at org.json.JSONObject.(JSONObject.java:172)
 at com.zsoft.signala.transport.longpolling.JSONHelper.ToJSONObject(JSONHelper.java:12)
 at com.zsoft.signala.transport.longpolling.ConnectedState$2.onComplete(ConnectedState.java:120)
 at com.turbomanage.httpclient.android.DoHttpRequestTask.onPostExecute(DoHttpRequestTask.java:56)
 at com.turbomanage.httpclient.android.DoHttpRequestTask.onPostExecute(DoHttpRequestTask.java:1)
 at android.os.AsyncTask.finish(AsyncTask.java:632)
 at android.os.AsyncTask.access$600(AsyncTask.java:177)
 at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645)
 at android.os.Handler.dispatchMessage(Handler.java:102)
 at android.os.Looper.loop(Looper.java:136)
 at android.app.ActivityThread.main(ActivityThread.java:5098)
 at java.lang.reflect.Method.invokeNative(Native Method)
 at java.lang.reflect.Method.invoke(Method.java:515)
 at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:780)
 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:596)
 at dalvik.system.NativeStart.main(Native Method)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ java.net.ConnectException: failed to connect to /123.56.130.232 (port 8089) after 1000ms: connect failed: ENETUNREACH (Network is unreachable)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ at libcore.io.IoBridge.connect(IoBridge.java:114)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:460)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ at java.net.Socket.connect(Socket.java:833)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ at com.android.okhttp.internal.Platform.connectSocket(Platform.java:131)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ at com.android.okhttp.Connection.connect(Connection.java:101)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:294)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ at com.android.okhttp.internal.http.HttpEngine.sendSocketRequest(HttpEngine.java:255)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:206)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ at com.android.okhttp.internal.http.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:345)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ at com.android.okhttp.internal.http.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:89)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ at com.turbomanage.httpclient.AbstractHttpClient.doHttpMethod(AbstractHttpClient.java:213)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ at com.turbomanage.httpclient.AsyncHttpClient.tryMany(AsyncHttpClient.java:185)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ at com.turbomanage.httpclient.android.DoHttpRequestTask.doInBackground(DoHttpRequestTask.java:40)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ at com.turbomanage.httpclient.android.DoHttpRequestTask.doInBackground(DoHttpRequestTask.java:1)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ at android.os.AsyncTask$2.call(AsyncTask.java:288)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ at java.util.concurrent.FutureTask.run(FutureTask.java:237)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ at java.lang.Thread.run(Thread.java:841)
 12-11 14:01:09.622 25809-25845/com.example.test W/System.err﹕ Caused by: libcore.io.ErrnoException: connect failed: ENETUNREACH (Network is unreachable)
 12-11 14:01:09.632 25809-25845/com.example.test W/System.err﹕ at libcore.io.Posix.connect(Native Method)
 12-11 14:01:09.632 25809-25845/com.example.test W/System.err﹕ at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:85)
 12-11 14:01:09.632 25809-25845/com.example.test W/System.err﹕ at libcore.io.IoBridge.connectErrno(IoBridge.java:144)
 12-11 14:01:09.632 25809-25845/com.example.test W/System.err﹕ at libcore.io.IoBridge.connect(IoBridge.java:112)
 12-11 14:01:09.632 25809-25845/com.example.test W/System.err﹕ ... 19 more
 12-11 14:01:09.632 25809-25845/com.example.test W/System.err﹕ com.turbomanage.httpclient.HttpRequestException: java.net.ConnectException: failed to connect to /123.56.130.232 (port 8089) after 1000ms: connect failed: ENETUNREACH (Network is unreachable)
 12-11 14:01:09.632 25809-25845/com.example.test W/System.err﹕ at com.turbomanage.httpclient.AbstractHttpClient.doHttpMethod(AbstractHttpClient.java:235)
 12-11 14:01:09.632 25809-25845/com.example.test W/System.err﹕ at com.turbomanage.httpclient.AsyncHttpClient.tryMany(AsyncHttpClient.java:185)
 12-11 14:01:09.632 25809-25845/com.example.test W/System.err﹕ at com.turbomanage.httpclient.android.DoHttpRequestTask.doInBackground(DoHttpRequestTask.java:40)
 12-11 14:01:09.632 25809-25845/com.example.test W/System.err﹕ at com.turbomanage.httpclient.android.DoHttpRequestTask.doInBackground(DoHttpRequestTask.java:1)
 12-11 14:01:09.632 25809-25845/com.example.test W/System.err﹕ at android.os.AsyncTask$2.call(AsyncTask.java:288)
 12-11 14:01:09.632 25809-25845/com.example.test W/System.err﹕ at java.util.concurrent.FutureTask.run(FutureTask.java:237)
 12-11 14:01:09.632 25809-25845/com.example.test W/System.err﹕ at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
 12-11 14:01:09.632 25809-25845/com.example.test W/System.err﹕ at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
 12-11 14:01:09.632 25809-25845/com.example.test W/System.err﹕ at java.lang.Thread.run(Thread.java:841)
 12-11 14:01:09.632 25809-25845/com.example.test W/System.err﹕ Caused by: java.net.ConnectException: failed to connect to /123.56.130.232 (port 8089) after 1000ms: connect failed: ENETUNREACH (Network is unreachable)
 12-11 14:01:09.632 25809-25845/com.example.test W/System.err﹕ at libcore.io.IoBridge.connect(IoBridge.java:114)
 12-11 14:01:09.632 25809-25845/com.example.test W/System.err﹕ at java.ne