4.4.1.1.md

4.4.1.1 创建/使用私有服务

私有服务是不能由其他应用启动的服务，因此它是最安全的服务。 当使用仅在应用中使用的私有服务时，只要您对该类使用显式意图，那么您就不必担心意外将它发送到任何其他应用。

下面展示了如何使用startService类型服务的示例代码。

要点（创建服务）：

1. 将导出属性显式设置为false。

2. 小心并安全地处理收到的意图，即使意图从相同应用发送。

3. 由于请求应用在同一应用中，所以可以发送敏感信息。

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="org.jssec.android.service.privateservice" >
    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:allowBackup="false" >
        <activity
            android:name=".PrivateUserActivity"
            android:label="@string/app_name"
            android:exported="true" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <!-- Private Service derived from Service class -->
        <!-- *** POINT 1 *** Explicitly set the exported attribute to false. -->
        <service android:name=".PrivateStartService" android:exported="false"/>
        <!-- Private Service derived from IntentService class -->
        <!-- *** POINT 1 *** Explicitly set the exported attribute to false. -->
        <service android:name=".PrivateIntentService" android:exported="false"/>
    </application>
</manifest>

PrivateStartService.java

package org.jssec.android.service.privateservice;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.widget.Toast;
public class PrivateStartService extends Service {
    // The onCreate gets called only one time when the service starts.
    @Override
    public void onCreate() {
        Toast.makeText(this, "PrivateStartService - onCreate()", Toast.LENGTH_SHORT).show();
    }
    // The onStartCommand gets called each time after the startService gets called.
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        // *** POINT 2 *** Handle the received intent carefully and securely,
        // even though the intent was sent from the same application.
        // Omitted, since this is a sample. Please refer to "3.2 Handling Input Data Carefully and Securely."
        String param = intent.getStringExtra("PARAM");
        Toast.makeText(this,
        String.format("PrivateStartService¥nReceived param: ¥"%s¥"", param),
        Toast.LENGTH_LONG).show();
        return Service.START_NOT_STICKY;
    }
    // The onDestroy gets called only one time when the service stops.
    @Override
    public void onDestroy() {
        Toast.makeText(this, "PrivateStartService - onDestroy()", Toast.LENGTH_SHORT).show();
    }
    @Override
    public IBinder onBind(Intent intent) {
        // This service does not provide binding, so return null
        return null;
    }
}

下面是使用私有服务的活动代码：

要点（使用服务）：

1. 使用指定类的显式意图，调用同一应用程序的服务。

2. 由于目标服务位于同一应用中，因此可以发送敏感信息。

3. 即使数据来自同一应用中的服务，也要小心并安全地处理收到的结果数据。

PrivateUserActivity.java

package org.jssec.android.service.privateservice;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
public class PrivateUserActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.privateservice_activity);
    }
    // --- StartService control ---
    public void onStartServiceClick(View v) {
        // *** POINT 4 *** Use the explicit intent with class specified to call a service in the same application.
        Intent intent = new Intent(this, PrivateStartService.class);
        // *** POINT 5 *** Sensitive information can be sent since the destination service is in the same application.
        intent.putExtra("PARAM", "Sensitive information");
        startService(intent);
    }
    public void onStopServiceClick(View v) {
        doStopService();
    }
    @Override
    public void onStop() {
        super.onStop();
        // Stop service if the service is running.
        doStopService();
    }
    private void doStopService() {
        // *** POINT 4 *** Use the explicit intent with class specified to call a service in the same application.
        Intent intent = new Intent(this, PrivateStartService.class);
        stopService(intent);
    }
    // --- IntentService control ---
    public void onIntentServiceClick(View v) {
        // *** POINT 4 *** Use the explicit intent with class specified to call a service in the same application.
        Intent intent = new Intent(this, PrivateIntentService.class);
        // *** POINT 5 *** Sensitive information can be sent since the destination service is in the same application.
        intent.putExtra("PARAM", "Sensitive information");
        startService(intent);
    }
}