[Settings] Apply proxy design to data usage

Enable proxy to subscription manager in data usage UI.

Bug: 141833767
Test: manual
make RunSettingsRoboTests -j ROBOTEST_FILTER=BillingCyclePreferenceTest
make RunSettingsRoboTests -j ROBOTEST_FILTER=CellDataPreferenceTest
make RunSettingsRoboTests -j ROBOTEST_FILTER=DataUsageListTest
make RunSettingsRoboTests -j ROBOTEST_FILTER=DataUsageSummaryTest
make RunSettingsRoboTests -j ROBOTEST_FILTER=DataUsageUtilsTest
make RunSettingsRoboTests -j ROBOTEST_FILTER=MobileDataEnabledListenerTest

Change-Id: Id119738dc16ece8767c088b9a0794997e4b0334f

src/com/android/settings/network/ActiveSubsciptionsListener.java

@@ -85,6 +85,7 @@ public abstract class ActiveSubsciptionsListener
     @VisibleForTesting
     BroadcastReceiver mSubscriptionChangeReceiver;
 
+    private Integer mMaxActiveSubscriptionInfos;
     private List<SubscriptionInfo> mCachedActiveSubscriptionInfo;
 
     /**
@@ -125,6 +126,24 @@ public abstract class ActiveSubsciptionsListener
         return mSubscriptionManager;
     }
 
+    /**
+     * Get current max. number active subscription info(s) been setup within device
+     *
+     * @return max. number of active subscription info(s)
+     */
+    public int getActiveSubscriptionInfoCountMax() {
+        int count = 0;
+        if (mMaxActiveSubscriptionInfos == null) {
+            count = getSubscriptionManager().getActiveSubscriptionInfoCountMax();
+            if (mIsMonitoringDataChange) {
+                mMaxActiveSubscriptionInfos = count;
+            }
+        } else {
+            count = mMaxActiveSubscriptionInfos.intValue();
+        }
+        return count;
+    }
+
     /**
      * Get a list of active subscription info
      *
@@ -134,7 +153,7 @@ public abstract class ActiveSubsciptionsListener
         if (mIsCachedDataAvailable) {
             return mCachedActiveSubscriptionInfo;
         }
-        mIsCachedDataAvailable = true;
+        mIsCachedDataAvailable = mIsMonitoringDataChange;
         mCachedActiveSubscriptionInfo = getSubscriptionManager().getActiveSubscriptionInfoList();
         return mCachedActiveSubscriptionInfo;
     }
@@ -163,6 +182,7 @@ public abstract class ActiveSubsciptionsListener
      */
     public void clearCache() {
         mIsCachedDataAvailable = false;
+        mMaxActiveSubscriptionInfos = null;
         mCachedActiveSubscriptionInfo = null;
     }
 

src/com/android/settings/network/GlobalSettingsChangeListener.java

@@ -33,7 +33,8 @@ import androidx.lifecycle.OnLifecycleEvent;
 /**
  * A listener for Settings.Global configuration change, with support of Lifecycle
  */
-abstract class GlobalSettingsChangeListener extends ContentObserver implements LifecycleObserver {
+public abstract class GlobalSettingsChangeListener extends ContentObserver
+        implements LifecycleObserver, AutoCloseable {
 
     /**
      * Constructor
@@ -41,7 +42,7 @@ abstract class GlobalSettingsChangeListener extends ContentObserver implements L
      * @param context of this listener
      * @param field field of Global Settings
      */
-    GlobalSettingsChangeListener(Context context, String field) {
+    public GlobalSettingsChangeListener(Context context, String field) {
         super(new Handler());
         mContext = context;
         mField = field;
@@ -92,6 +93,13 @@ abstract class GlobalSettingsChangeListener extends ContentObserver implements L
 
     @OnLifecycleEvent(ON_DESTROY)
     void onDestroy() {
+        close();
+    }
+
+    /**
+     * Implementation of AutoCloseable
+     */
+    public void close() {
         monitorUri(false);
         notifyChangeBasedOn(null);
     }

src/com/android/settings/network/MobileDataEnabledListener.java

@@ -17,53 +17,98 @@
 package com.android.settings.network;
 
 import android.content.Context;
-import android.database.ContentObserver;
-import android.net.Uri;
-import android.os.Handler;
 import android.provider.Settings;
 import android.telephony.SubscriptionManager;
 
 /** Helper class to listen for changes in the enabled state of mobile data. */
-public class MobileDataEnabledListener extends ContentObserver {
+public class MobileDataEnabledListener {
     private Context mContext;
     private Client mClient;
     private int mSubId;
+    /**
+     * There're 2 listeners both activated at the same time.
+     * For project that access MOBILE_DATA, only first listener is functional.
+     * For project that access "MOBILE_DATA + subId", first listener will be stopped when receiving
+     * any onChange from second listener.
+     */
+    private GlobalSettingsChangeListener mListener;
+    private GlobalSettingsChangeListener mListenerForSubId;
 
     public interface Client {
         void onMobileDataEnabledChange();
     }
 
+    /**
+     * Constructor
+     *
+     * @param context of this listener
+     * @param client callback when configuration changed
+     */
     public MobileDataEnabledListener(Context context, Client client) {
-        super(new Handler());
         mContext = context;
         mClient = client;
         mSubId = SubscriptionManager.INVALID_SUBSCRIPTION_ID;
     }
 
-    /** Starts listening to changes in the enabled state for data on the given subscription id. */
+    /**
+     * Starts listening to changes in the enabled state for data on the given subscription id.
+     *
+     * @param subId subscription id for enabled state of data subscription
+     */
     public void start(int subId) {
         mSubId = subId;
-        Uri uri;
-        if (mSubId == SubscriptionManager.INVALID_SUBSCRIPTION_ID) {
-            uri = Settings.Global.getUriFor(Settings.Global.MOBILE_DATA);
-        }  else {
-            uri = Settings.Global.getUriFor(Settings.Global.MOBILE_DATA + mSubId);
+
+        if (mListener == null) {
+            mListener = new GlobalSettingsChangeListener(mContext,
+                    Settings.Global.MOBILE_DATA) {
+                public void onChanged(String field) {
+                    mClient.onMobileDataEnabledChange();
+                }
+            };
         }
-        mContext.getContentResolver().registerContentObserver(uri, true /*notifyForDescendants*/,
-                this);
+        stopMonitorSubIdSpecific();
+
+        if (mSubId == SubscriptionManager.INVALID_SUBSCRIPTION_ID) {
+            return;
+        }
+
+        mListenerForSubId = new GlobalSettingsChangeListener(mContext,
+                Settings.Global.MOBILE_DATA + mSubId) {
+            public void onChanged(String field) {
+                stopMonitor();
+                mClient.onMobileDataEnabledChange();
+            }
+        };
     }
 
+    /**
+     * Get latest subscription id configured for listening
+     *
+     * @return subscription id
+     */
     public int getSubId() {
         return mSubId;
     }
 
-    public MobileDataEnabledListener stop() {
-        mContext.getContentResolver().unregisterContentObserver(this);
-        return this;
+    /**
+     * Stop listening to changes in the enabled state for data.
+     */
+    public void stop() {
+        stopMonitor();
+        stopMonitorSubIdSpecific();
     }
 
-    @Override
-    public void onChange(boolean selfChange) {
-        mClient.onMobileDataEnabledChange();
+    private void stopMonitor() {
+        if (mListener != null) {
+            mListener.close();
+            mListener = null;
+        }
+    }
+
+    private void stopMonitorSubIdSpecific() {
+        if (mListenerForSubId != null) {
+            mListenerForSubId.close();
+            mListenerForSubId = null;
+        }
     }
 }

src/com/android/settings/network/ProxySubscriptionManager.java

@@ -82,7 +82,6 @@ public class ProxySubscriptionManager extends SubscriptionManager.OnSubscription
             }
         };
 
-        mKeepCacheWhenOnStart = true;
         mSubsciptionsMonitor.start();
     }
 
@@ -90,7 +89,6 @@ public class ProxySubscriptionManager extends SubscriptionManager.OnSubscription
     private Context mContext;
     private ActiveSubsciptionsListener mSubsciptionsMonitor;
     private GlobalSettingsChangeListener mAirplaneModeMonitor;
-    private boolean mKeepCacheWhenOnStart;
 
     private List<OnActiveSubscriptionChangedListener> mActiveSubscriptionsListeners;
 
@@ -100,6 +98,12 @@ public class ProxySubscriptionManager extends SubscriptionManager.OnSubscription
         }
     }
 
+    @Override
+    public void onSubscriptionsChanged() {
+        clearCache();
+        notifyAllListeners();
+    }
+
     /**
      * Lifecycle for data within proxy
      *
@@ -118,15 +122,11 @@ public class ProxySubscriptionManager extends SubscriptionManager.OnSubscription
 
     @OnLifecycleEvent(ON_START)
     void onStart() {
-        if (!mKeepCacheWhenOnStart) {
-            mSubsciptionsMonitor.clearCache();
-        }
         mSubsciptionsMonitor.start();
     }
 
     @OnLifecycleEvent(ON_STOP)
     void onStop() {
-        mKeepCacheWhenOnStart = false;
         mSubsciptionsMonitor.stop();
     }
 
@@ -151,6 +151,15 @@ public class ProxySubscriptionManager extends SubscriptionManager.OnSubscription
         return mSubsciptionsMonitor.getSubscriptionManager();
     }
 
+    /**
+     * Get current max. number active subscription info(s) been setup within device
+     *
+     * @return max. number of active subscription info(s)
+     */
+    public int getActiveSubscriptionInfoCountMax() {
+        return mSubsciptionsMonitor.getActiveSubscriptionInfoCountMax();
+    }
+
     /**
      * Get a list of active subscription info
      *
@@ -183,6 +192,9 @@ public class ProxySubscriptionManager extends SubscriptionManager.OnSubscription
      * @param listener listener to active subscriptions change
      */
     public void addActiveSubscriptionsListener(OnActiveSubscriptionChangedListener listener) {
+        if (mActiveSubscriptionsListeners.contains(listener)) {
+            return;
+        }
         mActiveSubscriptionsListeners.add(listener);
     }