可能重复:
NetworkOnMainThreadException
长期以来,我一直在使用在AsyncTask
中执行http请求的通用代码。AsyncTask
返回一个HttpResponse
对象。一切都很好,gui线程从未冻结。
现在,突然之间,这就产生了一个NetworkOnMainThreadException
:
serverResponse.getEntity().getContent();
搞什么鬼??为什么要考虑联网??在我看来,这一行只是将响应转换为inputstream,不需要网络连接。谁做了这个决定?为什么他们认为这应该是网络?
异步任务:
public class AsyncHttpTask extends AsyncTask<HttpRequestInfo, Integer, HttpRequestInfo> {
public AsyncHttpTask() {
super();
}
protected HttpRequestInfo doInBackground(HttpRequestInfo... params) {
HttpRequestInfo rinfo = params[0];
try{
HttpClient client = new DefaultHttpClient();
HttpResponse resp = client.execute(rinfo.getRequest());
rinfo.setResponse(resp);
}
catch (Exception e) {
rinfo.setException(e);
}
return rinfo;
}
@Override
protected void onPostExecute(HttpRequestInfo rinfo) {
super.onPostExecute(rinfo);
rinfo.requestFinished();
}
回调接口:
public interface HttpCallback {
public void onResponse(HttpResponse serverResponse);
public void onError(Exception e);
}
httprequestinfo:
public class HttpRequestInfo {
private HttpUriRequest request_;
private HttpCallback callback_;
private Exception exception_;
private HttpResponse response_;
public HttpRequestInfo(HttpUriRequest request, HttpCallback callback) {
super();
request_ = request;
callback_ = callback;
}
public HttpUriRequest getRequest() {
return request_;
}
public void setRequest(HttpUriRequest request) {
request_ = request;
}
public HttpCallback getCallback() {
return callback_;
}
public void setCallback(HttpCallback callback) {
callback_ = callback;
}
public Exception getException() {
return exception_;
}
public void setException(Exception exception) {
exception_ = exception;
}
public HttpResponse getResponse() {
return response_;
}
public void setResponse(HttpResponse response) {
response_ = response;
}
public void requestFinished(){
if(exception_ != null){
callback_.onError(exception_);
}
else {
callback_.onResponse(response_);
}
}
}
然后我使用jackson将json响应转换为一个对象。这就是发生异常的地方:
@Override
public <T> T handleResponse(HttpResponse serverResponse, Class<T> typeOfResponse) {
ObjectMapper mapper = new ObjectMapper();
mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
T responseObject = null;
try {
responseObject = mapper.readValue(serverResponse.getEntity().getContent(),typeOfResponse); //THIS LINE IS EVIL
} catch (JsonParseException e) {
throw new ARException("Couldn't handle the response because the http response contained malformed json.",e);
} catch (JsonMappingException e) {
throw new ARException("Mapping the json response to the response object " + typeOfResponse + " failed.",e);
} catch (IllegalStateException e) {
throw new ARException("Couldn't convert the http response to an inputstream because of illegal state.",e);
} catch (IOException e) {
throw new ARException("Couldn't convert the http response to an inputstream.",e);
}
return responseObject;
}
最佳答案
因为您必须在单独的线程而不是主线程中使用网络。您可以使用AsyncTask或Thread+Handler。如果使用的是asynctask all work with network,则必须在doinbackground部分执行。