我想启动一项服务，该服务会在固定的时间间隔（使用警报服务）后向服务器发送地理位置。即，广播接收器启动后的服务，如何在该服务中运行AsynTask？
我试过，但我收到此错误:: caused by:java.lang.RuntimeException:can't create handler inside thread that has not called looper.prepare
我制作了以下代码：
public void onReceive(Context context, Intent intent) {
// Start periodic service.
Calendar cal = Calendar.getInstance();
Intent srvIntent = new Intent(context, NoLopper.class); // StartAtBootService
PendingIntent pIntent = PendingIntent.getService(context, 0, srvIntent, 0);
// Use context argument to access service
AlarmManager alarm =(AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
// Repeat every 5 seconds
alarm.setInexactRepeating(AlarmManager.RTC_WAKEUP, cal.getTimeInMillis(),
10000, pIntent);
}
这是我的服务类
public class NoLopper extends Service
{
public static final String url = "http://10.0.2.2:1010/LociServer/HelloWorldServlet";
String p="50" ;
String imei="111" ;
String returnString=null;
Integer returnedValue=0;
@Override
public IBinder onBind(Intent arg0) {
// TODO Auto-generated method stub
return null;
}
/* (non-Javadoc)
* @see android.app.Service#onCreate()
*/
@Override
public void onCreate() {
// TODO Auto-generated method stub
super.onCreate();
Toast.makeText(this, "onCreate of lopper", Toast.LENGTH_LONG)
.show();
}
/* (non-Javadoc)
* @see android.app.Service#onStartCommand(android.content.Intent, int, int)
*/
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
// TODO Auto-generated method stub
Toast.makeText(this, "on comand of lopper", Toast.LENGTH_LONG)
.show();
GetXMLTask task = new GetXMLTask();
task.execute(new String[] { url });
return START_STICKY;
}
private class GetXMLTask extends AsyncTask<String, Void, String>
{
@Override
protected String doInBackground(String... urls)
{
String output = null;
// for (String url : urls)
// {
// output = getOutputFromUrl(url); // a loop
// }
// return output;
// }
// private String getOutputFromUrl(String url)
// {
// String output = null;
try
{
DefaultHttpClient httpClient = new DefaultHttpClient();
//ResponseHandler<String> res = new BasicResponseHandler();
HttpPost httpPost = new HttpPost(url);
try {
String lat="latitude valueee";
String lng ="put convereted double into string of latlng variables" ;
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
nameValuePairs.add(new BasicNameValuePair("paramlat", lat));
nameValuePairs.add(new BasicNameValuePair("paramlng", lng));
//nameValuePairs.add(new BasicNameValuePair("Gender", gender));
httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs)); // namevaluepair variable are being senddd as entity
HttpResponse httpResponse = httpClient.execute(httpPost); //request the request To execute;; httpRequest variable can be used in future ,ie can be given a warning to the user back
// String response = httpClient.execute(httpPost, res);
Toast.makeText(r.fn.sender.NoLopper.this, "from getxmTAsk inner try block", Toast.LENGTH_LONG).show();
HttpEntity httpEntity = httpResponse.getEntity(); //getting the responsed data ;called entites means onject
output = EntityUtils.toString(httpEntity);
}//end of inner try block
catch (UnsupportedEncodingException e)
{
e.printStackTrace();
}
catch (ClientProtocolException e)
{
e.printStackTrace();
}
catch (IOException e)
{
e.printStackTrace();
}
} //end of outer try block
catch(Exception e)
{
Log.e("log_tag", "Error in http connection "+e.toString());
}
Toast.makeText(r.fn.sender.NoLopper.this, "after catch block", Toast.LENGTH_LONG).show();
return output;
} //end of getOutputFromUrl method
@Override
protected void onPostExecute(String output)
{
// tv.setText(output);
//can be used for camera/turn off the phone keyField intent opening values ,if servlet returns open cam. instruction
// Log.d("Helloworld", "ur returned list array "+output.toString());
Toast.makeText(r.fn.sender.NoLopper.this, "onPost method exe block", Toast.LENGTH_LONG).show();
}
} // end of GetXMLTask
}
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05-01 12:29:05.823: W/Trace(867): Unexpected value from nativeGetEnabledTags: 0
05-01 12:29:05.823: W/Trace(867): Unexpected value from nativeGetEnabledTags: 0
05-01 12:29:05.903: D/gralloc_goldfish(867): Emulator without GPU emulation detected.
05-01 12:29:05.943: W/Trace(867): Unexpected value from nativeGetEnabledTags: 0
05-01 12:29:05.993: W/Trace(867): Unexpected value from nativeGetEnabledTags: 0
05-01 12:29:06.803: E/log_tag(867): Error in http connection java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
05-01 12:29:06.803: W/dalvikvm(867): threadid=11: thread exiting with uncaught exception (group=0x40a70930)
05-01 12:29:06.843: E/AndroidRuntime(867): FATAL EXCEPTION: AsyncTask #1
05-01 12:29:06.843: E/AndroidRuntime(867): java.lang.RuntimeException: An error occured while executing doInBackground()
05-01 12:29:06.843: E/AndroidRuntime(867): at android.os.AsyncTask$3.done(AsyncTask.java:299)
05-01 12:29:06.843: E/AndroidRuntime(867): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)
05-01 12:29:06.843: E/AndroidRuntime(867): at java.util.concurrent.FutureTask.setException(FutureTask.java:219)
05-01 12:29:06.843: E/AndroidRuntime(867): at java.util.concurrent.FutureTask.run(FutureTask.java:239)
05-01 12:29:06.843: E/AndroidRuntime(867): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
05-01 12:29:06.843: E/AndroidRuntime(867): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
05-01 12:29:06.843: E/AndroidRuntime(867): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
05-01 12:29:06.843: E/AndroidRuntime(867): at java.lang.Thread.run(Thread.java:856)
05-01 12:29:06.843: E/AndroidRuntime(867): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
05-01 12:29:06.843: E/AndroidRuntime(867): at android.os.Handler.<init>(Handler.java:197)
05-01 12:29:06.843: E/AndroidRuntime(867): at android.os.Handler.<init>(Handler.java:111)
05-01 12:29:06.843: E/AndroidRuntime(867): at android.widget.Toast$TN.<init>(Toast.java:324)
05-01 12:29:06.843: E/AndroidRuntime(867): at android.widget.Toast.<init>(Toast.java:91)
05-01 12:29:06.843: E/AndroidRuntime(867): at android.widget.Toast.makeText(Toast.java:238)
05-01 12:29:06.843: E/AndroidRuntime(867): at r.fn.sender.NoLopper$GetXMLTask.doInBackground(NoLopper.java:157)
05-01 12:29:06.843: E/AndroidRuntime(867): at r.fn.sender.NoLopper$GetXMLTask.doInBackground(NoLopper.java:1)
05-01 12:29:06.843: E/AndroidRuntime(867): at android.os.AsyncTask$2.call(AsyncTask.java:287)
05-01 12:29:06.843: E/AndroidRuntime(867): at java.util.concurrent.FutureTask.run(FutureTask.java:234)
05-01 12:29:06.843: E/AndroidRuntime(867): ... 4 more
答案 0 :(得分：1)
您正在尝试从doInBackground（）访问UI，这是一个非UI线程。从doInBackgroud（）中删除Toast条消息。您可以使用Log来检查。
从Toast.makeText(r.fn.sender.NoLopper.this, "after catch block", Toast.LENGTH_LONG).show();
doInBackground()