我有这个 Asynctask 应该计算用户的位置。Asynctask 中的代码在 Asynctask 之外运行良好,所以我知道我的错误是在安排 Asynctask 时,我非常不熟悉。
Asynctask 在 onClick 方法中由这一行运行:
new GetCurrentCity().execute();
这是 GetCurrentCity 本身:
private class GetCurrentCity extends AsyncTask<String, Void, String>{
@Override
protected String doInBackground(String... args) {
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);
Location location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
double longitude = location.getLongitude();
double latitude = location.getLatitude();
Geocoder gcd = new Geocoder(getApplicationContext(), Locale.getDefault());
try {
List<Address> addresses = gcd.getFromLocation(latitude, longitude, 1);
if(addresses != null) {
Address returnedAddress = addresses.get(0);
for(int i=0; i<returnedAddress.getMaxAddressLineIndex(); i++) {
strReturnedAddress = (returnedAddress.getAddressLine(i)).toString();
}
}
}
catch (IOException e) {
e.printStackTrace();
}
return strReturnedAddress;
}
protected void onPostExecute(String useless2){
test.setText(strReturnedAddress);
}
}
正如我所说,我是一个有不同线程的新手,所以如果这是一个非常简单的问题,请原谅。
另外,我还在为参数苦苦挣扎,所以我觉得问题出在它们身上;然而,在来这里询问之前,我已经尝试了我能想到的一切。
提前感谢您,祝您有美好的一天!
编辑:这是当前的 logcat
07-10 20:24:08.175: D/OpenGLRenderer(15827): Enabling debug mode 0
07-10 20:24:08.435: I/TextToSpeech(15827): Connected to ComponentInfo{com.google.android.tts/com.google.android.tts.GoogleTTSService}
07-10 20:24:13.460: W/dalvikvm(15827): threadid=13: thread exiting with uncaught exception (group=0x41471930)
07-10 20:24:13.465: E/AndroidRuntime(15827): FATAL EXCEPTION: AsyncTask #3
07-10 20:24:13.465: E/AndroidRuntime(15827): java.lang.RuntimeException: An error occured while executing doInBackground()
07-10 20:24:13.465: E/AndroidRuntime(15827): at android.os.AsyncTask$3.done(AsyncTask.java:299)
07-10 20:24:13.465: E/AndroidRuntime(15827): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)
07-10 20:24:13.465: E/AndroidRuntime(15827): at java.util.concurrent.FutureTask.setException(FutureTask.java:219)
07-10 20:24:13.465: E/AndroidRuntime(15827): at java.util.concurrent.FutureTask.run(FutureTask.java:239)
07-10 20:24:13.465: E/AndroidRuntime(15827): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
07-10 20:24:13.465: E/AndroidRuntime(15827): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
07-10 20:24:13.465: E/AndroidRuntime(15827): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
07-10 20:24:13.465: E/AndroidRuntime(15827): at java.lang.Thread.run(Thread.java:856)
07-10 20:24:13.465: E/AndroidRuntime(15827): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
07-10 20:24:13.465: E/AndroidRuntime(15827): at android.os.Handler.<init>(Handler.java:197)
07-10 20:24:13.465: E/AndroidRuntime(15827): at android.os.Handler.<init>(Handler.java:111)
07-10 20:24:13.465: E/AndroidRuntime(15827): at android.location.LocationManager$ListenerTransport$1.<init>(LocationManager.java:197)
07-10 20:24:13.465: E/AndroidRuntime(15827): at android.location.LocationManager$ListenerTransport.<init>(LocationManager.java:197)
07-10 20:24:13.465: E/AndroidRuntime(15827): at android.location.LocationManager.wrapListener(LocationManager.java:820)
07-10 20:24:13.465: E/AndroidRuntime(15827): at android.location.LocationManager.requestLocationUpdates(LocationManager.java:833)
07-10 20:24:13.465: E/AndroidRuntime(15827): at android.location.LocationManager.requestLocationUpdates(LocationManager.java:430)
07-10 20:24:13.465: E/AndroidRuntime(15827): at com.example.realapptest1.MainActivity$GetCurrentCity.doInBackground(MainActivity.java:306)
07-10 20:24:13.465: E/AndroidRuntime(15827): at com.example.realapptest1.MainActivity$GetCurrentCity.doInBackground(MainActivity.java:1)
07-10 20:24:13.465: E/AndroidRuntime(15827): at android.os.AsyncTask$2.call(AsyncTask.java:287)
07-10 20:24:13.465: E/AndroidRuntime(15827): at java.util.concurrent.FutureTask.run(FutureTask.java:234)
07-10 20:24:13.465: E/AndroidRuntime(15827): ... 4 more