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我建立了一項服務，其中使用GPS和wifi（我自己寫的）計算用戶的位置。計算完成後，SMS會發回給用戶。請注意，此服務是由SMS啓動的。 WIFI和GPS可以正常工作。但是當組合在一起時會出錯。位置和定時器和nullpointerexception
其實我得到了兩個錯誤，第一個是：java.lang.NullPointerException。
然後我的應用程序再次崩潰，我得到這個：了java.lang.RuntimeException：無法啓動服務[email protected]與空：顯示java.lang.NullPointerException
好像GPS正在嘗試在第一個服務完成後啓動另一個服務。我嘗試了很多方法，但無法解決這個問題。有人請舉手。
下面是代碼
public class ScanService extends Service {
WifiManager wifi;
TimerTask timerTask1;
private static Timer timer = new Timer();
String receipt;
String message = "";
int count = 0;
Location location;
String gpsInfo = "";
LocationManager locationManager;
@Override
public void onCreate() {
wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
timer = new Timer();
timerTask1 = new TimerTask() {
@Override
public void run() {
// TODO Auto-generated method stub
Log.d("timer", "timer alright");
if (count >=0 && count <= 24) {
count++;
scan();//do the scanning
}
else if (count == 25) {
locating();//do the calculation
sendSMS();
}
}
};
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
criteria.setCostAllowed(true);
criteria.setPowerRequirement(Criteria.POWER_LOW);
String provider = locationManager.getBestProvider(criteria, true);
location = locationManager.getLastKnownLocation(provider);
if (location != null) {
double lat = location.getLatitude();
double lng = location.getLongitude();
message += " http://ditu.google.cn/?q=" + lat + "," + lng;
}
else {
message += "unable to get gps info";
}
}
@Override
public void onStart(Intent intent, int startId) {
super.onStart(intent, startId);
Toast.makeText(this, "service onStart", 0).show();
wifi.setWifiEnabled(false);
wifi.setWifiEnabled(true);
timer.scheduleAtFixedRate(timerTask1, 30000, 500);
}
@Override
public void onDestroy() {
super.onDestroy();
timer.cancel();
Toast.makeText(this, "service onDestroy", Toast.LENGTH_LONG).show();
}
public void sendSMS() {
String SENT = "SMS_SENT";
String DELIVERED = "SMS_DELIVERED";
PendingIntent sentPI = PendingIntent.getBroadcast(this, 0, new Intent(SENT), 0);
PendingIntent deliveredPI = PendingIntent.getBroadcast(this, 0, new Intent(DELIVERED), 0);
Log.d("sendSMS", "in sndSMS");
//Log.d("message", message);
BroadcastReceiver sentReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context arg0, Intent arg1) {
switch(getResultCode()) {
case Activity.RESULT_OK:
Toast.makeText(getBaseContext(), "SMS sent",
Toast.LENGTH_SHORT).show();
break;
case SmsManager.RESULT_ERROR_GENERIC_FAILURE:
Toast.makeText(getBaseContext(), "Generic failure",
Toast.LENGTH_SHORT).show();
break;
case SmsManager.RESULT_ERROR_NO_SERVICE:
Toast.makeText(getBaseContext(), "No service",
Toast.LENGTH_SHORT).show();
break;
case SmsManager.RESULT_ERROR_NULL_PDU:
Toast.makeText(getBaseContext(), "Null PDU",
Toast.LENGTH_SHORT).show();
break;
case SmsManager.RESULT_ERROR_RADIO_OFF:
Toast.makeText(getBaseContext(), "Radio off",
Toast.LENGTH_SHORT).show();
break;
}
}
};
BroadcastReceiver deliveredReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
switch(getResultCode()) {
case Activity.RESULT_OK:
Toast.makeText(getBaseContext(), "SMS delivered",
Toast.LENGTH_SHORT).show();
stopSelf();
break;
case Activity.RESULT_CANCELED:
Toast.makeText(getBaseContext(), "SMS not delivered",
Toast.LENGTH_SHORT).show();
stopSelf();
break;
}
}
};
registerReceiver(sentReceiver, new IntentFilter(SENT));
registerReceiver(deliveredReceiver, new IntentFilter(DELIVERED));
SmsManager sms = SmsManager.getDefault();
sms.sendTextMessage(receipt, null, message, sentPI, deliveredPI);
timer.cancel();
Log.d("timer", "timer cancelled");
}
}