Get the List of Activities in the Foreground State

Introduction to App ForegroundActivity

Demo	Permission	Description
	- The application requires post notification permission. - Declare permissions in AndroidManifest.xml permission POST_NOTIFICATIONS	- In MainActivity, I created 2 CardView elements to display basic information about the two methods. When you press the "More" button, you will navigate to the details of each method. - Each method's screen consists of two parts:         + Header Section: Introduction, a button to request permissions, and a notification displaying the content of the current activity.         + List Section: Displays a list of activities. - After granting the required permissions, the application will create a notification showing the activity currently in the foreground. You can switch to another application to test this feature.

Method 1: Using UsageStatsManager

Description

UsageStatsManager can be used to retrieve the usage history of applications, including information about the time and frequency of app usage on the device through the queryUsageStats method. The most recently used application is highly likely to be in the foreground state. Periodically, call the queryUsageStats method to update the data.

Advantages

• Easy to implement.
• Does not require access to personal information.

Disadvantages

• Data is updated with a delay (not in real time).

Google Policy Notes

• Using UsageStatsManager requires declaring the PACKAGE_USAGE_STATS permission. This permission does not require manual user consent but must be enabled in Settings > Apps > Special app access > Usage access.
• The application must be transparent with users about how this data is used and comply with Google Play’s privacy policies.

Implementation Steps

Click to expand

1. Declare permissions in AndroidManifest.xml:

   <uses-permission
        android:name="android.permission.PACKAGE_USAGE_STATS"
        tools:ignore="ProtectedPermissions" />

2. Check permission in the code:

   private boolean isUsageAccessGranted() {
        AppOpsManager appOpsManager = (AppOpsManager) getSystemService(Context.APP_OPS_SERVICE);
        int mode = appOpsManager.checkOpNoThrow(AppOpsManager.OPSTR_GET_USAGE_STATS,
                android.os.Process.myUid(), getPackageName());
        return mode == AppOpsManager.MODE_ALLOWED;
    }

3. Query information using UsageStatsManager:

   UsageStatsManager usageStatsManager =
           (UsageStatsManager) context.getSystemService(Context.USAGE_STATS_SERVICE);
   
   if (usageStatsManager == null) {
       return new ArrayList<>(); // Return empty list if UsageStatsManager is unavailable
   }
   
   // Query usage stats for the last 24 hours
   List<UsageStats> usageStatsList = usageStatsManager.queryUsageStats(
           UsageStatsManager.INTERVAL_DAILY,
           currentTime - (24 * 60 * 60 * 1000), // Start time (24 hours ago)
           currentTime // End time (now)
   );
   
   if (usageStatsList == null || usageStatsList.isEmpty()) {
       return new ArrayList<>(); // Return empty list if no data is available
   }

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Method 2: Using AccessibilityService

Description

AccessibilityService has the ability to monitor apps in the foreground, allowing you to retrieve app information via the TYPE_WINDOW_STATE_CHANGED event.

Advantages

• Data is updated in real-time.

Disadvantages

• Complex to implement.
• Granted permissions can be revoked when the application is closed.
• When granting AccessibilityService access, other information like text content, gesture behavior, etc., may also be accessed.

Google Policy Notes

• Using AccessibilityService requires the app to clearly explain the reason for requesting this permission and not misuse it to collect unrelated data.
• According to Google Play policy, this permission is only accepted if it serves a purpose that aids the user, such as supporting disabled users.
• Misuse of this permission could result in the app being removed from Google Play.

Implementation Steps

Click to expand

1. Create a class that extends AccessibilityService:

   public class AccessibilityServiceExtend extends AccessibilityService {
       @Override
       public void onAccessibilityEvent(AccessibilityEvent event) {
           if (event.getEventType() == AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED) {
               // Get the package name and activity name
               ComponentName componentName = new ComponentName(
                       event.getPackageName().toString(),
                       event.getClassName().toString()
               );
   
               String currentPackageName = componentName.getPackageName();
               String currentActivityName = componentName.flattenToShortString();
           }
       }
   
       @Override
       public void onInterrupt() {
       }
   }

2. Declare the service in AndroidManifest.xml:

   <!--android:foregroundServiceType="mediaPlayback" is used for the post notification feature-->
   <service
        android:name=".AccessibilityServiceExtend"
        android:exported="true"
        android:foregroundServiceType="mediaPlayback"
        android:permission="android.permission.BIND_ACCESSIBILITY_SERVICE">
        <intent-filter>
            <action android:name="android.accessibilityservice.AccessibilityService" />
        </intent-filter>
   
        <meta-data
            android:name="android.accessibilityservice"
            android:resource="@xml/accessibility_service_config" />
   </service>

3. Configure the file res/xml/accessibility_config.xml:

   <accessibility-service xmlns:android="http://schemas.android.com/apk/res/android"
        android:accessibilityEventTypes="typeWindowStateChanged"
        android:accessibilityFeedbackType="feedbackGeneric"
        android:canRetrieveWindowContent="false"
        android:description="@string/app_name"
        android:notificationTimeout="100" />

4. Activate the service in the device’s Accessibility settings:

   • The user needs to enable the service in Settings > Accessibility > ForegroundActivity.

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Comparison of the 2 Methods

Feature	UsageStatsManager	AccessibilityService
Setup	Easy	Complex
Update Frequency	Delayed	Real-time
Permission Scope	Does not require sensitive access	Requires high and sensitive permissions
Accuracy	Depends on query timing	High accuracy via system events
Policy Compliance	Requires transparent declaration	Strict requirements to avoid misuse

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Note: The choice of method depends on project requirements and the priority among performance, security, and compliance with Google’s policies.