Improve launch time for Apps & notifications page

In original design, we reload usage data at least thrice
for showing recent apps.

For now, we only reload usage data once in constuctor.
And we reload data again when we are calling updateState.

Test: Open App & notifications page, and then I compare the lauch time
with P platform device.
Fixes: 126013076

Change-Id: Ida769f28a4419125e1948e36658686ee55bf51a5

src/com/android/settings/applications/RecentAppsPreferenceController.java

@@ -82,6 +82,8 @@ public class RecentAppsPreferenceController extends BasePreferenceController
     Preference mAllAppPref;
     @VisibleForTesting
     Preference mDivider;
+    @VisibleForTesting
+    boolean mIsFirstLaunch;
 
     private final PackageManager mPm;
     private final UsageStatsManager mUsageStatsManager;
@@ -93,6 +95,7 @@ public class RecentAppsPreferenceController extends BasePreferenceController
     private Fragment mHost;
     private Calendar mCal;
     private List<UsageStats> mStats;
+    private List<UsageStats> mRecentApps;
     private boolean mHasRecentApps;
 
     static {
@@ -115,6 +118,9 @@ public class RecentAppsPreferenceController extends BasePreferenceController
         mIconDrawableFactory = IconDrawableFactory.newInstance(mContext);
         mPowerManager = mContext.getSystemService(PowerManager.class);
         mUsageStatsManager = mContext.getSystemService(UsageStatsManager.class);
+        mRecentApps = new ArrayList<>();
+        mIsFirstLaunch = true;
+        reloadData();
     }
 
     public void setFragment(Fragment fragment) {
@@ -123,8 +129,7 @@ public class RecentAppsPreferenceController extends BasePreferenceController
 
     @Override
     public int getAvailabilityStatus() {
-        reloadData();
+        return mRecentApps.isEmpty() ? AVAILABLE_UNSEARCHABLE : AVAILABLE;
-        return getDisplayableRecentAppList().isEmpty() ? AVAILABLE_UNSEARCHABLE : AVAILABLE;
     }
 
     @Override
@@ -152,7 +157,11 @@ public class RecentAppsPreferenceController extends BasePreferenceController
     @Override
     public void updateState(Preference preference) {
         super.updateState(preference);
+        // In order to improve launch time, we don't load data again at first launch.
+        if (!mIsFirstLaunch) {
+            reloadData();
             refreshUi();
+        }
         // Show total number of installed apps as See all's summary.
         new InstalledAppCounter(mContext, InstalledAppCounter.IGNORE_INSTALL_REASON,
                 mContext.getPackageManager()) {
@@ -167,6 +176,7 @@ public class RecentAppsPreferenceController extends BasePreferenceController
                 }
             }
         }.execute();
+        mIsFirstLaunch = false;
     }
 
     @Override
@@ -177,11 +187,9 @@ public class RecentAppsPreferenceController extends BasePreferenceController
 
     @VisibleForTesting
     void refreshUi() {
-        reloadData();
+        if (mRecentApps != null && !mRecentApps.isEmpty()) {
-        final List<UsageStats> recentApps = getDisplayableRecentAppList();
-        if (recentApps != null && !recentApps.isEmpty()) {
             mHasRecentApps = true;
-            displayRecentApps(recentApps);
+            displayRecentApps();
         } else {
             mHasRecentApps = false;
             displayOnlyAppInfo();
@@ -197,6 +205,8 @@ public class RecentAppsPreferenceController extends BasePreferenceController
                 : mUsageStatsManager.queryUsageStats(
                         UsageStatsManager.INTERVAL_BEST, mCal.getTimeInMillis(),
                         System.currentTimeMillis());
+
+        updateDisplayableRecentAppList();
     }
 
     private void displayOnlyAppInfo() {
@@ -206,10 +216,10 @@ public class RecentAppsPreferenceController extends BasePreferenceController
         mRecentAppsPreference.setVisible(false);
     }
 
-    private void displayRecentApps(List<UsageStats> recentApps) {
+    private void displayRecentApps() {
         int showAppsCount = 0;
 
-        for (UsageStats stat : recentApps) {
+        for (UsageStats stat : mRecentApps) {
             final AppEntityInfo appEntityInfoInfo = createAppEntity(stat);
             if (appEntityInfoInfo != null) {
                 mAppEntitiesController.setAppEntity(showAppsCount++, appEntityInfoInfo);
@@ -246,8 +256,8 @@ public class RecentAppsPreferenceController extends BasePreferenceController
                 .build();
     }
 
-    private List<UsageStats> getDisplayableRecentAppList() {
+    private void updateDisplayableRecentAppList() {
-        final List<UsageStats> recentApps = new ArrayList<>();
+        mRecentApps.clear();
         final Map<String, UsageStats> map = new ArrayMap<>();
         final int statCount = mStats.size();
         for (int i = 0; i < statCount; i++) {
@@ -273,13 +283,12 @@ public class RecentAppsPreferenceController extends BasePreferenceController
             if (appEntry == null) {
                 continue;
             }
-            recentApps.add(stat);
+            mRecentApps.add(stat);
             count++;
             if (count >= AppEntitiesHeaderController.MAXIMUM_APPS) {
                 break;
             }
         }
-        return recentApps;
     }
 
 

tests/robotests/src/com/android/settings/applications/RecentAppsPreferenceControllerTest.java

@@ -25,9 +25,9 @@ import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.ArgumentMatchers.anyLong;
 import static org.mockito.ArgumentMatchers.argThat;
-import static org.mockito.Mockito.doNothing;
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
@@ -146,6 +146,7 @@ public class RecentAppsPreferenceControllerTest {
         when(mUsageStatsManager.queryUsageStats(anyInt(), anyLong(), anyLong()))
                 .thenReturn(stats);
         mAppEntry.info = mApplicationInfo;
+        mController.reloadData();
 
         assertThat(mController.getAvailabilityStatus()).isEqualTo(AVAILABLE);
     }
@@ -157,13 +158,17 @@ public class RecentAppsPreferenceControllerTest {
     }
 
     @Test
-    public void displayPreferenceAndUpdateState_shouldRefreshUi() {
+    public void displayPreference_shouldNotReloadData() {
-        doNothing().when(mController).refreshUi();
-
         mController.displayPreference(mScreen);
-        mController.updateState(mScreen);
 
-        verify(mController, times(2)).refreshUi();
+        verify(mController, never()).reloadData();
+    }
+
+    @Test
+    public void displayPreference_shouldRefreshUi() {
+        mController.displayPreference(mScreen);
+
+        verify(mController).refreshUi();
     }
 
     @Test
@@ -173,6 +178,25 @@ public class RecentAppsPreferenceControllerTest {
         assertThat(mController.mAppEntitiesController).isNotNull();
     }
 
+    @Test
+    public void updateState_firstLaunch_shouldNotReloadData() {
+        mController.mIsFirstLaunch = true;
+
+        mController.updateState(mRecentAppsPreference);
+
+        verify(mController, never()).reloadData();
+    }
+
+    @Test
+    public void updateState_afterFirstLaunch_shouldReloadDataAndRefreshUi() {
+        mController.mIsFirstLaunch = false;
+
+        mController.updateState(mRecentAppsPreference);
+
+        verify(mController).reloadData();
+        verify(mController).refreshUi();
+    }
+
     @Test
     public void updateState_threeValidRecentOpenAppsSet_setAppEntityThreeTime() {
         final List<UsageStats> stats = new ArrayList<>();
@@ -203,6 +227,7 @@ public class RecentAppsPreferenceControllerTest {
         when(mUsageStatsManager.queryUsageStats(anyInt(), anyLong(), anyLong()))
                 .thenReturn(stats);
         mAppEntry.info = mApplicationInfo;
+        mController.mIsFirstLaunch = false;
 
         mController.updateState(mRecentAppsPreference);
 
@@ -243,6 +268,7 @@ public class RecentAppsPreferenceControllerTest {
         when(mUsageStatsManager.queryUsageStats(anyInt(), anyLong(), anyLong()))
                 .thenReturn(stats);
         mAppEntry.info = mApplicationInfo;
+        mController.mIsFirstLaunch = false;
 
         mController.updateState(mRecentAppsPreference);
 
@@ -274,6 +300,7 @@ public class RecentAppsPreferenceControllerTest {
         when(mUsageStatsManager.queryUsageStats(anyInt(), anyLong(), anyLong()))
                 .thenReturn(stats);
         mAppEntry.info = mApplicationInfo;
+        mController.mIsFirstLaunch = false;
 
         mController.updateState(mRecentAppsPreference);
 
@@ -314,6 +341,7 @@ public class RecentAppsPreferenceControllerTest {
         // Make sure stat2 is considered an instant app.
         ReflectionHelpers.setStaticField(AppUtils.class, "sInstantAppDataProvider",
                 (InstantAppDataProvider) (ApplicationInfo info) -> info == stat2Entry.info);
+        mController.mIsFirstLaunch = false;
 
         mController.updateState(mRecentAppsPreference);
 
@@ -389,6 +417,7 @@ public class RecentAppsPreferenceControllerTest {
                 .thenReturn(new ResolveInfo());
         when(mUsageStatsManager.queryUsageStats(anyInt(), anyLong(), anyLong()))
                 .thenReturn(stats);
+        mController.mIsFirstLaunch = false;
 
         mController.updateState(mRecentAppsPreference);