Question

我正在尝试在后台运行应用程序，但是当应用程序立即启动时，应用程序将关闭（不会出现错误）。我在主要活动中使用了asynk任务。

代码：

package com.android.trace;

public class LocationStat extends Activity {

double logi;
double lat;
long MINIMUM_DISTANCE_CHANGE_FOR_UPDATES = 1; // in Meters
long MINIMUM_TIME_BETWEEN_UPDATES = 1000; // in Millisecon
Location loc;
LocationManager manager;
TextView t;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    new MyLocationAsyncTask().execute();

}

public void onStart() {
    super.onStart();

    new MyLocationAsyncTask().execute();

}

private class MyLocationAsyncTask extends AsyncTask<Void, Location, Void> implements LocationListener {

    //private Location l;
    //location management variables to track and maintain user location
    @Override
    protected Void doInBackground(Void... arg0) {
        t = (TextView) findViewById(R.id.text);
        manager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        manager.requestLocationUpdates(
                LocationManager.GPS_PROVIDER,
                MINIMUM_TIME_BETWEEN_UPDATES,
                MINIMUM_DISTANCE_CHANGE_FOR_UPDATES,
                new MyLocationAsyncTask());


        return onLocationChanged();
    }

    //this method is never executed i dont know why...?
    public Void onLocationChanged() {
        if (manager != null) {
            LocationStat l = new LocationStat();
            loc = manager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
            lat = loc.getLatitude();
            logi = loc.getLongitude();
            t.setText(" Your Location :\nlongitude:" + logi + "\nlatitude: " + lat);                 //Log.d("Your Location", ""+latLocation);
            l.webcall(logi, lat);
        }
        return null;
    }

    public void onLocationChanged(Location location) {
        onLocationChanged();


    }

    public void onProviderDisabled(String provider) {
    }

    public void onProviderEnabled(String provider) {
        // TODO Auto-generated method stub
    }

    public void onStatusChanged(String provider, int status, Bundle extras) {
        // TODO Auto-generated method stub
    }
}

public void webcall(double logi, double lat) {
    InputStream is = null;
    String result = "";
    //the year data to send
    ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
    nameValuePairs.add(new BasicNameValuePair("logitude", Double.toString(logi)));
    nameValuePairs.add(new BasicNameValuePair("latitude", Double.toString(lat)));

    //http post
    try {
        HttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new HttpPost("http://10.0.2.2/location.php");
        httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
        HttpResponse response = httpclient.execute(httppost);
        HttpEntity entity = response.getEntity();
        is = entity.getContent();
    } catch (Exception e) {
        Toast.makeText(LocationStat.this, "Error in http connection " + e.toString(), Toast.LENGTH_LONG).show();
    }
    //convert response to string
    try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(is, "iso-8859-1"), 8);
        StringBuilder sb = new StringBuilder();
        String line = null;
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        }
        is.close();

        result = sb.toString();




        Toast.makeText(LocationStat.this, result, Toast.LENGTH_LONG).show();
    } catch (Exception e) {
        Toast.makeText(LocationStat.this, "Error converting result " + e.toString(), Toast.LENGTH_LONG).show();
    }

}

启动活动的服务代码代码：

import android.app.Service;
import android.content.Intent;
import android.os.IBinder;


import android.widget.Toast;

public class MyService extends Service {

String tag="TestService";
@Override
public void onCreate() {

   Intent dialogIntent = new Intent(this, LocationStat.class);
       dialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

      this.startActivity(dialogIntent);
    }

@Override
public void onStart(Intent intent, int startId) {      
   super.onStart(intent, startId);  


 }

    @Override
   public int onStartCommand(Intent intent, int flags, int startId) {

   return START_STICKY;
  }
  @Override
   public void onDestroy() {
   super.onDestroy();
   Toast.makeText(this, "Service destroyed...", Toast.LENGTH_LONG).show();
  }

   @Override
    public IBinder onBind(Intent intent) {
   return null;
   }
}

用于在启动时启动服务的广播接收器是

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;

public class MyBroadcastReceiver extends BroadcastReceiver {

  public void onReceive(Context context, Intent intent) {
    Intent startServiceIntent = new Intent(context, MyService.class);
    startServiceIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    context.startService(startServiceIntent);

  }
}

活动，服务和广播接收者的清单权限如下

<service android:enabled="true" android:name=".MyService">
            <intent-filter >
                <action android:name="com.android.trace.MyService"/>

            </intent-filter>
        </service>

        <receiver android:name="com.android.trace.MyBroadcastReceiver">  
            <intent-filter>  
              <action android:name="android.intent.action.BOOT_COMPLETED" />  
             </intent-filter>  
        </receiver> 


    <activity
        android:name=".LocationStat"
        android:label="@string/title_activity_location_stat" >
        <intent-filter>
                <action android:name="android.intent.action.MAIN" /> 

             <category android:name="android.intent.category.LAUNCHER" /> 
        </intent-filter>

    </activity>


 <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

有没有人经历过同样的事情？

Answer 1

使用Service代替Activity来执行后台长期作业

Answer 2

您只能从主GUI线程在GUI上使用setText和其他操作。您正尝试从已启动的后台线程执行此操作。

您必须在onPostExecute上实现AsyncTask函数并从那里修改GUI。

Answer 3

内存不足，捕获LOG onDestoy（）方法

Answer 4

您是否在android manifest文件中提到过您的接收器，在manifest file，

中添加这一堆代码

 <receiver
        android:name=".MyBroadcastReceiver" >
        <intent-filter android:priority="1000">

            <action />

        </intent-filter>

    </receiver>

启动活动时，申请流程将关闭

4 个答案: