android - 从 android 小部件内部启动 VPNService

Question

我正在我的 Activity 中启动一个 VPNService，我想在服务启动后启动一些线程。这就是我启动服务的方式:

Intent intent = VpnService.prepare(getActivity());
if (intent != null) {
    startActivityForResult(intent, 123);
else {
    onActivityResult(123, Activity.RESULT_OK, null);
}

然后在 onActivityResult 中我开始我的线程

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == 123) {
        // Start some thread
    }
}

现在我希望能够从我的应用程序的小部件中执行所有这些操作。看来我只能从小部件内部使用 startActivity，这是使用 VPNService 的正确方法。有什么办法可以从我的小部件实现这一点？也许来自 startActivity 的一些回调？

Answer 1

没有太多的小部件经验，但建议这样做:

• 仅为该 startActivityForResult() 调用创建虚拟 Activity (请注意，我正在为该 Activity 使用特定主题 @android:style/Theme.NoDisplay)；
• 从小部件启动虚拟 Activity ；
• 使用 SharedPreferences 将结果存储在 Activity 中并为小部件发送广播；

下面是示例项目:

AndroidManifest.xml:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
          package="com.alexstarc.testapp"
          android:versionCode="1"
          android:versionName="1.0">

    <uses-sdk android:minSdkVersion="19"
        android:targetSdkVersion="19"/>

    <application
        android:label="@string/app_name"
        android:icon="@drawable/ic_launcher"
        android:allowBackup="true">
        <activity
            android:name=".MyActivity"
            android:label="@string/app_name"
            android:theme="@android:style/Theme.NoDisplay">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>

        <receiver android:name="TestWidgetProvider"
                  android:exported="false">
            <intent-filter>
                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />

                <!-- Custom actions -->
                <action android:name="com.alexstarc.testapp.ACTION_BTN" />
                <action android:name="com.alexstarc.testapp.ACTION_VPN_RESULT" />
            </intent-filter>
            <meta-data android:name="android.appwidget.provider"
                       android:resource="@xml/appwidget_info" />
        </receiver>
    </application>
</manifest>

appwidget_info.xml:

<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
    android:minWidth="180dp"
    android:minHeight="40dp"
    android:updatePeriodMillis="0"
    android:initialLayout="@layout/appwidget"
    android:resizeMode="horizontal|vertical"
    android:widgetCategory="home_screen"
    android:previewImage="@drawable/widget_preview"/>

应用程序小部件.xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="4dp"
    android:background="@drawable/appwidget_bg">

    <ImageButton
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/launchVPN"
        android:src="@android:drawable/ic_media_play"/>

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/resultText"
        style="@android:style/TextAppearance.DeviceDefault.Medium.Inverse"
        android:layout_toRightOf="@id/launchVPN"
        android:text="@string/test_text"
        android:gravity="bottom"/>
</RelativeLayout>

MyActivity.java:

public class MyActivity extends Activity {

    private static final int VPN_LAUNCH_CODE = 123;

    public static String SHARED_PREFS_NAME = "shared_prefs";
    public static String RESULT_VPN = "vpn_launch_result";
    public static String ACTION_VPN_RESULT = "com.alexstarc.testapp.ACTION_VPN_RESULT";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        Intent intent = VpnService.prepare(MyActivity.this);
        if (intent != null) {
            startActivityForResult(intent, VPN_LAUNCH_CODE);
        } else {
            onActivityResult(VPN_LAUNCH_CODE, Activity.RESULT_OK, null);
        }
    }

    @Override
    protected void onActivityResult(final int requestCode, final int resultCode, final Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == 123) {
            getSharedPreferences(SHARED_PREFS_NAME, MODE_MULTI_PROCESS).edit().putString(RESULT_VPN, "VPN Result is " + resultCode).commit();

            final Intent resultIntent = new Intent(ACTION_VPN_RESULT);

            sendBroadcast(resultIntent);
            finish();
        }
    }
}

TestWidgetProvider.java:

public final class TestWidgetProvider extends AppWidgetProvider {

    private static final String ACTION_START_BTN = "com.alexstarc.testapp.ACTION_BTN";

    // TODO: Use Shared Prefs for this
    private static int sWidgetId = 0;
    private static boolean sVPNDone = false;

    @Override
    public void onUpdate(final Context context, final AppWidgetManager appWidgetManager, final int[] appWidgetIds) {
        for (int widgetId : appWidgetIds) {
            updateWidget(context, appWidgetManager, widgetId);
        }

        sWidgetId = appWidgetIds[0];
    }

    /**
     * Updates single App Widget
     *
     * @param context {@link android.content.Context}
     * @param appWidgetManager {@link android.appwidget.AppWidgetManager}
     * @param widgetId of current widget
     */
    private static void updateWidget(final Context context, final AppWidgetManager appWidgetManager, final int widgetId) {
        final ArrayList<Integer> widgets = new ArrayList<Integer>();

        final Intent btnClickIntent = new Intent(context, TestWidgetProvider.class);

        btnClickIntent.setAction(ACTION_START_BTN);

        final PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, btnClickIntent, 0);

        // Get the layout for the App Widget and attach an on-click listener
        // to the button
        RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.appwidget);

        views.setOnClickPendingIntent(R.id.launchVPN, pendingIntent);

        // Update from shared preferences after activity  was launched
        if (sVPNDone) {
            views.setTextViewText(R.id.resultText,
                    context.getSharedPreferences(MyActivity.SHARED_PREFS_NAME, Context.MODE_PRIVATE).getString(MyActivity.RESULT_VPN, "No result"));
        }

        appWidgetManager.updateAppWidget(widgetId, views);
    }

    @Override
    public void onReceive(final Context context, final Intent intent) {
        final String action = intent.getAction();

        if (ACTION_START_BTN.equals(action)) {
            // Start listening service
            final Intent vpnActivityIntent = new Intent(context, MyActivity.class);

            vpnActivityIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            context.startActivity(vpnActivityIntent);
        } else if (MyActivity.ACTION_VPN_RESULT.equals(action)) {
            sVPNDone = true;
            updateWidget(context, AppWidgetManager.getInstance(context), sWidgetId);
        } else {
            super.onReceive(context, intent);
        }
    }
}