我在NetworkOnMainThreadException执行两个网络请求时收到AsyncTask。在第一个请求中，我获得了Response XML，在第二个请求中，我下载了Image InputStream中要使用的BitmapFactory.decodeStream。请在下面找到例外：
07-10 08:20:49.961: W/System.err(8570): android.os.NetworkOnMainThreadException
07-10 08:20:49.961: W/System.err(8570): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117)
07-10 08:20:49.961: W/System.err(8570): at libcore.io.BlockGuardOs.recvfrom(BlockGuardOs.java:163)
07-10 08:20:49.971: W/System.err(8570): at libcore.io.IoBridge.recvfrom(IoBridge.java:513)
07-10 08:20:49.971: W/System.err(8570): at java.net.PlainSocketImpl.read(PlainSocketImpl.java:488)
07-10 08:20:49.971: W/System.err(8570): at java.net.PlainSocketImpl.access$000(PlainSocketImpl.java:46)
07-10 08:20:49.971: W/System.err(8570): at java.net.PlainSocketImpl$PlainSocketInputStream.read(PlainSocketImpl.java:240)
07-10 08:20:49.981: W/System.err(8570): at java.io.BufferedInputStream.read(BufferedInputStream.java:304)
public class FetchDataTask extends AsyncTask {
@Override
protected Object doInBackground(Object... object) {
String url = (String)object[0];
TASK_TYPE type = (TASK_TYPE)object[1];
Object[] objects = new Object[4];
switch(type)
{
case FETCH_NOTICES:
publishProgress("Fetching notices ...");
// Request # 1 to get the JSON XML
String data = apiRequestGET(url);
ArrayList<Notices> notices = extractUserFriendsDataFromXML(data);
Notices notice = notices.get(0);
publishProgress("Fetching done.");
objects[0] = type;
objects[1] = new ArrayList<Notices>(notices.subList(1, notices.size()));
objects[2] = notice.getUniversityTitle();
try {
// Request # 2 to get the InputStream
objects[3] = (InputStream) new URL(notice.getUniversityLogo()).getContent();
} catch (MalformedURLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
return objects;
}
return null;
}
private String apiRequestGET(String requestString)
{
HttpClient httpClient = new DefaultHttpClient();
HttpContext localContext = new BasicHttpContext();
HttpGet httpGet = new HttpGet(requestString);
String responseText = null;
try
{
HttpResponse response = httpClient.execute(httpGet, localContext);
System.out.println("Some Response" +response);
HttpEntity entity = response.getEntity();
responseText = EntityUtils.toString(entity);
}
catch (Exception e1)
{
return e1.getLocalizedMessage();
}
return responseText;
}
}
有谁能告诉我我做错了什么？ doInBackground中的两个网络请求无法完成？
提前致谢！
07-10 08:52:18.672: W/System.err(9213): android.os.NetworkOnMainThreadException
07-10 08:52:18.682: W/System.err(9213): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117)
07-10 08:52:18.682: W/System.err(9213): at libcore.io.BlockGuardOs.recvfrom(BlockGuardOs.java:163)
07-10 08:52:18.682: W/System.err(9213): at libcore.io.IoBridge.recvfrom(IoBridge.java:513)
07-10 08:52:18.692: W/System.err(9213): at java.net.PlainSocketImpl.read(PlainSocketImpl.java:488)
07-10 08:52:18.692: W/System.err(9213): at java.net.PlainSocketImpl.access$000(PlainSocketImpl.java:46)
07-10 08:52:18.692: W/System.err(9213): at java.net.PlainSocketImpl$PlainSocketInputStream.read(PlainSocketImpl.java:240)
07-10 08:52:18.702: W/System.err(9213): at java.io.BufferedInputStream.read(BufferedInputStream.java:304)
07-10 08:52:18.702: W/System.err(9213): at libcore.net.http.FixedLengthInputStream.read(FixedLengthInputStream.java:45)
07-10 08:52:18.702: W/System.err(9213): at java.io.BufferedInputStream.fillbuf(BufferedInputStream.java:168)
07-10 08:52:18.702: W/System.err(9213): at java.io.BufferedInputStream.read(BufferedInputStream.java:309)
07-10 08:52:18.712: W/System.err(9213): at android.graphics.BitmapFactory.nativeDecodeStream(Native Method)
07-10 08:52:18.712: W/System.err(9213): at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:529)
07-10 08:52:18.712: W/System.err(9213): at android.graphics.BitmapFactory.decodeStream(BitmapFactory.java:601)
07-10 08:52:18.722: W/System.err(9213): at com.alpha.noticeslist.NoticeListActivity.dataFetched(NoticeListActivity.java:145)
07-10 08:52:18.722: W/System.err(9213): at com.alpha.web.FetchDataTask.onPostExecute(FetchDataTask.java:124)
07-10 08:52:18.732: W/System.err(9213): at android.os.AsyncTask.finish(AsyncTask.java:631)
07-10 08:52:18.732: W/System.err(9213): at android.os.AsyncTask.access$600(AsyncTask.java:177)
07-10 08:52:18.732: W/System.err(9213): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644)
07-10 08:52:18.732: W/System.err(9213): at android.os.Handler.dispatchMessage(Handler.java:99)
07-10 08:52:18.742: W/System.err(9213): at android.os.Looper.loop(Looper.java:137)
07-10 08:52:18.742: W/System.err(9213): at android.app.ActivityThread.main(ActivityThread.java:5041)
07-10 08:52:18.752: W/System.err(9213): at java.lang.reflect.Method.invokeNative(Native Method)
07-10 08:52:18.752: W/System.err(9213): at java.lang.reflect.Method.invoke(Method.java:511)
07-10 08:52:18.752: W/System.err(9213): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
07-10 08:52:18.752: W/System.err(9213): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
07-10 08:52:18.762: W/System.err(9213): at dalvik.system.NativeStart.main(Native Method)
我从onPostExecute调用InputStream传递的函数时得到错误：
public void dataFetched(InputStream inputstream)
{
Bitmap bitmap = BitmapFactory.decodeStream(inputstream);
logo.setImageBitmap(bitmap);
}
@Override
protected void onPostExecute(Object result){
statusDialog.dismiss();
Object[] objects = (Object[])result;
TASK_TYPE type = (TASK_TYPE)objects[0];
switch(type)
{
case FETCH_NOTICES:
((NoticeListActivity)callerActivity).dataFetched((InputStream)objects[3]);
break;
}
}
答案 0 :(得分：1)
我认为您收到了错误，因为虽然您在后台主题中获得了对InputStream的引用，但实际上当您在decodeStream中调用onPostExecute时，您会从流中读取该内容在主线程上运行
移动电话：
Bitmap bitmap = BitmapFactory.decodeStream(inputstream);
进入doInBackground并传递bitmap而不是输入流
答案 1 :(得分：0)
确保您致电myFetchDataTask.execute()。您是否直接致电doInBackground()，如果是这样，它将无效，如果没有，请发布您执行AsyncTask的方式。
希望它有所帮助！
答案 2 :(得分：0)
你的班级应该是：
class FetchDataTask extends AsyncTask<Object, String, Void>
{
@Override
protected Void doInBackground(Object... params) {
//code here
publishProgress("");
return null;
}
@Override
protected void onProgressUpdate(String... values) {
// TODO Auto-generated method stub
super.onProgressUpdate(values);
}
}
您可以执行new FetchDataTask.execute([your parameter]);
答案 3 :(得分：-1)
使用以下代码执行异步任务：
private class FetchDataTask extends AsyncTask <String, Void, Void>
{
Object[] objects = new Object[4];
protected void onPreExecute() {
}
@Override
protected Void doInBackground(String... paramsObj) {
String url = (String)object[0];
TASK_TYPE type = (TASK_TYPE)object[1];
switch(type)
{
case FETCH_NOTICES:
publishProgress("Fetching notices ...");
// Request # 1 to get the JSON XML
String data = apiRequestGET(url);
ArrayList<Notices> notices = extractUserFriendsDataFromXML(data);
Notices notice = notices.get(0);
publishProgress("Fetching done.");
objects[0] = type;
objects[1] = new ArrayList<Notices>(notices.subList(1, notices.size()));
objects[2] = notice.getUniversityTitle();
try {
// Request # 2 to get the InputStream
objects[3] = (InputStream) new URL(notice.getUniversityLogo()).getContent();
} catch (MalformedURLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
return null;
}
protected void onPostExecute(Void unused)
{
// Do action with objects
}
}
从调用方法中，使用：
new FetchDataTask().execute();