AVIMConversationQuery.query(callback)中的callback回调收不到。
当网络切换回来或者变动后，有时会收不到回调事件，怎么解？有没有在调用AVIMConversationQuery.query之前的一些判断方法，能够判断leancloud通讯良好，然后我再调用AVIMConversationQuery.query的方法？
16年8月31日
16年9月2日
这个回调应该是可以收到的，如果是网络变动查询失败的情况下，会返回AVIMException。
com.gu.patientclient W/System.err: com.avos.avoscloud.AVException: java.net.UnknownHostException
com.gu.patientclient W/System.err: at com.avos.avoscloud.AppRouterManager$1.onFailure(AppRouterManager.java:168)
com.gu.patientclient W/System.err: at com.avos.avoscloud.GenericObjectCallback.onFailure(GenericObjectCallback.java:14)
com.gu.patientclient W/System.err: at com.avos.avoscloud.GetHttpResponseHandler.onFailure(GetHttpResponseHandler.java:123)
com.gu.patientclient W/System.err: at com.avos.avoscloud.AsyncHttpResponseHandler.onFailure(AsyncHttpResponseHandler.java:37)
com.gu.patientclient W/System.err: at com.avos.avoscloud.okhttp.Call$AsyncCall.execute(Call.java:174)
com.gu.patientclient W/System.err: at com.avos.avoscloud.okhttp.internal.NamedRunnable.run(NamedRunnable.java:33)
com.gu.patientclient W/System.err: at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
com.gu.patientclient W/System.err: at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
com.gu.patientclient W/System.err: at java.lang.Thread.run(Thread.java:841)
com.gu.patientclient W/System.err: Caused by: java.net.UnknownHostException
com.gu.patientclient W/System.err: at com.avos.avoscloud.DNSAmendNetwork.lookup(DNSAmendNetwork.java:63)
com.gu.patientclient W/System.err: at com.avos.avoscloud.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:185)
com.gu.patientclient W/System.err: at com.avos.avoscloud.okhttp.internal.http.RouteSelector.nextProxy(RouteSelector.java:154)
com.gu.patientclient W/System.err: at com.avos.avoscloud.okhttp.internal.http.RouteSelector.next(RouteSelector.java:96)
com.gu.patientclient W/System.err: at com.avos.avoscloud.okhttp.internal.http.HttpEngine.createNextConnection(HttpEngine.java:346)
com.gu.patientclient W/System.err: at com.avos.avoscloud.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:329)
com.gu.patientclient W/System.err: at com.avos.avoscloud.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:247)
com.gu.patientclient W/System.err: at com.avos.avoscloud.okhttp.Call.getResponse(Call.java:274)
com.gu.patientclient W/System.err: at com.avos.avoscloud.okhttp.Call$ApplicationInterceptorChain.proceed(Call.java:232)
com.gu.patientclient W/System.err: at com.avos.avoscloud.PaasClient$RequestStatisticInterceptor.intercept(PaasClient.java:976)
com.gu.patientclient W/System.err: at com.avos.avoscloud.okhttp.Call$ApplicationInterceptorChain.proceed(Call.java:221)
com.gu.patientclient W/System.err: at com.avos.avoscloud.okhttp.Call.getResponseWithInterceptorChain(Call.java:194)
com.gu.patientclient W/System.err: at com.avos.avoscloud.okhttp.Call.access$100(Call.java:32)
com.gu.patientclient W/System.err: at com.avos.avoscloud.okhttp.Call$AsyncCall.execute(Call.java:160)
com.gu.patientclient W/System.err: ... 4 more
程序长时间放后台，再进去，报这些错误java.net.UnknownHostException
