サービス初歩

例:
ServiceActivity.class

public class ServiceActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Button button1 = (Button)findViewById(R.id.button1);
        Button button2 = (Button)findViewById(R.id.button2);
        button1.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				Intent i = new Intent();
				i.setClass(ServiceActivity.this, FirstService.class);
				startService(i);
			}
		});
        button2.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				Intent i = new Intent();
				i.setClass(ServiceActivity.this, FirstService.class);
				stopService(i);
			}
		});
    		}
}

FirstService.class

public class FirstService extends Service {
	@Override
	public IBinder onBind(Intent arg0) {
		// TODO Auto-generated method stub
		System.out.println("service onBind");
		return null;
	}

	@Override
	public void onCreate() {
		// TODO Auto-generated method stub
		super.onCreate();
		System.out.println("service onCreate");
	}

	@Override
	public void onDestroy() {
		// TODO Auto-generated method stub
		super.onDestroy();
		System.out.println("service onDestroy");
	}

	@Override
	public void onStart(Intent intent, int startId) {
		// TODO Auto-generated method stub
		super.onStart(intent, startId);
		System.out.println("service onStart");
		System.out.println("startId:"+startId);
	}
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.cn"
      android:versionCode="1"
      android:versionName="1.0">
    <uses-sdk android:minSdkVersion="4" />

    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".ServiceActivity"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
		<service android:name=".FirstService"></service>
    </application>
</manifest>

PS:バージョンandroid 2になったら.1以上、onStartメソッドの代わりにonStartCommandメソッドを使用します.