Question

我正在使用 startService（Intent intent）方法启动服务。当我调用此功能时，它会到达服务的 onCreate ，但无法调用 onStartCommand 。这是我的代码 -

@Override
public void onReceive(Context context, Intent intent) {
    // Send a text notification to the screen.
    Log.e("mudit", "Action: " + intent.getAction());

    try {
        ConnectivityManager connManager = (ConnectivityManager) context
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo info = connManager.getActiveNetworkInfo();
        Log.e("mudit", "getType: " + info.getType());
        Log.e("mudit", "isConnected: " + info.isConnected());
        if (info.isConnected()) {

            Intent newinIntent = new Intent(context, service.class);
            context.startService(newinIntent);
        }

    } catch (Exception e) {
        e.printStackTrace();
        Intent newinIntent = new Intent(context, service.class);
        context.stopService(newinIntent);

    }

}

服务代码 -

package com.android.service;

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

public class service extends Service {

    @Override
    public IBinder onBind(Intent arg0) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public void onCreate() {
        super.onCreate();
        Toast.makeText(this, "Service created...", Toast.LENGTH_LONG).show();
    }

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

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

        Toast.makeText(this, "onStartCommand...", Toast.LENGTH_LONG).show();
        return 1;
    }

}

Manifest.xml -

<receiver class=".AReceiver" android:name=".AReceiver">
        <intent-filter>
            <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
        </intent-filter>
    </receiver>
    <service class=".service" android:name=".service"
        android:enabled="true" android:icon="@drawable/icon">
    </service>

Answer 1

未绑定服务：它在后台无限期地运行，甚至也开始了服务结束的活动。

绑定服务：它将持续到活动的生命时间。

活动可以通过startService()启动服务，并通过stopService()停止。   如果活动想要与服务互动，则可以使用bindService()。

在使用活动提供的意图数据调用onCreate()之后，调用第一个onStartCommand。

Source

Answer 2

首先，您应在@Override之前添加onStartCommand(..)，然后确保Android项目的目标高于2.0 。

Answer 3

larsVogel解决了这个问题（和许多其他人一样）in this excellent post。

这就是我如何调整他的代码来创建连接接收器，监视用户何时连接到WIFI网络以批量上传使用数据：

在清单文件中，放置一个接收器并在＆lt;的结束标记之前声明一个服务。 / application＆gt;：

    <receiver android:name=".ConnMonitor" android:enabled="true">
        <intent-filter>
            <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
        </intent-filter>
    </receiver>
    <service android:name=".BatchUploadGpsData" ></service>

</application>

在名为ConnMonitor.java的单独文件中创建广播接收器类（请取消注释Log调用以便能够正确监视流）

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.util.Log;

public class ConnMonitor extends BroadcastReceiver {
    private String TAG = "TGtracker";

    @Override
    public void onReceive(Context context, Intent intent) {
        //String typeName = "";
        String state = "";
        int type = -1;
        ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService( Context.CONNECTIVITY_SERVICE );
        NetworkInfo test = (NetworkInfo) connectivityManager.getActiveNetworkInfo();
        //Log.v(TAG,"there has been a CONNECTION CHANGE -> "+intent.getExtras().get(ConnectivityManager.EXTRA_NETWORK_INFO));
        try {
            //typeName = test.getTypeName().toString();
            type = test.getType();
            state = test.getState().toString();
            //Log.i(TAG,"type -> '"+typeName +"'  state -> '"+state+"'"   );
        } catch (Exception e) {
            //typeName = "null";
            type = -1;
            state = "DISCONNECTED";
            //Log.i(TAG,"type -> error1 "+e.getMessage()+ "   cause = "+e.getCause()   );
        }

        if ( (type == 1)  &&  (state == "CONNECTED") ) {
            //Log.i(TAG, "I am soooo friggin uploadin on this beautiful WIFI connection ");
            Intent batchUploadDataService = new Intent(context, BatchUploadGpsData.class);
            context.startService(batchUploadDataService);
        } else {
            //Log.e(TAG,"NO FOUND MATCH type -> '"+typeName +"'  state -> '"+state+"'"   );
        }
    }
}

最后，创建一个服务BatchUploadGpsData.java，如下所示：

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

public class BatchUploadGpsData extends Service {
    final String TAG = "TGtracker";

    @Override
    public void onCreate() {
        Log.e(TAG, "here i am, rockin like a hurricane.   onCreate service");
    // this service tries to upload and terminates itself whether it is successful or not 
    // but it only effectively DOES anything while it is created 
    // (therefore, you can call 1 million times if uploading isnt done, nothing happens)
    // if you comment this next line, you will be able to see that it executes onCreate only the first it is called
    // the reason i do this is that the broadcast receiver is called at least twice every time you have a new change of connectivity state with successful connection to wifi
        this.stopSelf();
    }
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        //Log.i(TAG, "Received start id " + startId + ": " + intent);
        Log.e(TAG, "call me redundant BABY!  onStartCommand service");
        // this service is NOT supposed to execute anything when it is called
        // because it may be called inumerous times in repetition
        // all of its action is in the onCreate - so as to force it to happen ONLY once
        return 1;
    }
    @Override
    public IBinder onBind(Intent intent) {
        // TODO Auto-generated method stub
        return null;
    }

}

这不是伪代码，这是实际代码，在Android 2.2及更高版本上测试并运行。

测试此服务的方法是关闭并重新启动Android上的WIFI服务（关闭wifi路由器也会起作用）。但是此代码不会验证您是否有效连接到网络。为此，我建议您发出一个httpclient请求并检查调用的结果。超出了本讨论的范围。

注意：由于服务在与UI相同的线程上运行，因此我强烈建议您根据具体需要在单独的线程或asynctask上实现正确的上传。你也可以在一个单独的线程上运行整个服务，但这仍然不是讨论的范围，尽管在这些情况下是标准做法。

Answer 4

我相信，您无法访问任何UI组件，如Dialog甚至是服务中的Toast。

试试这个。

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

/*    Toast.makeText(this, "onStartCommand...", Toast.LENGTH_LONG).show();
    return 1; */

    Log.i("YourService", "Yes this works.");
}

Answer 5

首先，将您的课程命名为其他内容是我的建议，以避免混淆。这里的第二个例子是我对我所拥有的服务的明确要求。我在调用服务时使用完整路径名，因为它们与我的应用程序不在同一个包中。

<service android:name="com.public.service.UploaderService" android:icon="@drawable/vgbio"></service>

以下是我的服务类的要点，

package com.public.service;
....
public class UploaderService extends Service{
....
}

第三，确保将@Override用于onStartCommand（）。

在android平台上启动服务

5 个答案: