Cache mechanism for Storage page with work profile

Apply a cache mechanism to prevent the flicker problem from entering
Storage page.

Bug: 191117970
Test: manual test
1) Create a work profile with TestDPC
2) The loading spinner will be shown when entering Storage page after
   the first boot.
3) Back to Settings homepage and switch back to Storage page, the
   loading spinner shouldn't be shown.
4) The preference order shouldn't be updated after changing the storage
   size.

Change-Id: I518679f90c63e12f61f08d08d5ed3f3900825be2

src/com/android/settings/dashboard/profileselector/ProfileSelectStorageFragment.java

@@ -20,6 +20,7 @@ import android.app.Activity;
 import android.app.settings.SettingsEnums;
 import android.content.Context;
 import android.os.Bundle;
+import android.os.UserHandle;
 import android.os.storage.DiskInfo;
 import android.os.storage.StorageEventListener;
 import android.os.storage.StorageManager;
@@ -36,6 +37,7 @@ import com.android.settings.deviceinfo.StorageCategoryFragment;
 import com.android.settings.deviceinfo.VolumeOptionMenuController;
 import com.android.settings.deviceinfo.storage.AutomaticStorageManagementSwitchPreferenceController;
 import com.android.settings.deviceinfo.storage.DiskInitFragment;
+import com.android.settings.deviceinfo.storage.StorageCacheHelper;
 import com.android.settings.deviceinfo.storage.StorageEntry;
 import com.android.settings.deviceinfo.storage.StorageSelectionPreferenceController;
 import com.android.settings.deviceinfo.storage.StorageUsageProgressBarPreferenceController;
@@ -71,6 +73,8 @@ public class ProfileSelectStorageFragment extends ProfileSelectFragment {
     private StorageSelectionPreferenceController mStorageSelectionController;
     private StorageUsageProgressBarPreferenceController mStorageUsageProgressBarController;
     private VolumeOptionMenuController mOptionMenuController;
+    private boolean mIsLoadedFromCache;
+    private StorageCacheHelper mStorageCacheHelper;
 
     private final StorageEventListener mStorageEventListener = new StorageEventListener() {
         @Override
@@ -246,11 +250,20 @@ public class ProfileSelectStorageFragment extends ProfileSelectFragment {
         }
 
         initializeOptionsMenu(activity);
+
+        if (mStorageCacheHelper.hasCachedSizeInfo()) {
+            mIsLoadedFromCache = true;
+            mStorageEntries.clear();
+            mStorageEntries.addAll(
+                    StorageUtils.getAllStorageEntries(getContext(), mStorageManager));
+            refreshUi();
+        }
     }
 
     @Override
     public void onAttach(Context context) {
         super.onAttach(context);
+        mStorageCacheHelper = new StorageCacheHelper(getContext(), UserHandle.myUserId());
         use(AutomaticStorageManagementSwitchPreferenceController.class).setFragmentManager(
                 getFragmentManager());
         mStorageSelectionController = use(StorageSelectionPreferenceController.class);
@@ -281,9 +294,14 @@ public class ProfileSelectStorageFragment extends ProfileSelectFragment {
     public void onResume() {
         super.onResume();
 
+        if (mIsLoadedFromCache) {
+            mIsLoadedFromCache = false;
+        } else {
             mStorageEntries.clear();
-        mStorageEntries.addAll(StorageUtils.getAllStorageEntries(getContext(), mStorageManager));
+            mStorageEntries.addAll(
+                    StorageUtils.getAllStorageEntries(getContext(), mStorageManager));
             refreshUi();
+        }
         mStorageManager.registerListener(mStorageEventListener);
     }
 

src/com/android/settings/deviceinfo/StorageCategoryFragment.java

@@ -39,6 +39,7 @@ import com.android.settings.dashboard.DashboardFragment;
 import com.android.settings.dashboard.profileselector.ProfileSelectFragment;
 import com.android.settings.deviceinfo.storage.SecondaryUserController;
 import com.android.settings.deviceinfo.storage.StorageAsyncLoader;
+import com.android.settings.deviceinfo.storage.StorageCacheHelper;
 import com.android.settings.deviceinfo.storage.StorageEntry;
 import com.android.settings.deviceinfo.storage.StorageItemPreferenceController;
 import com.android.settings.deviceinfo.storage.UserIconLoader;
@@ -90,6 +91,8 @@ public class StorageCategoryFragment extends DashboardFragment
     private boolean mIsWorkProfile;
     private int mUserId;
     private Preference mFreeUpSpacePreference;
+    private boolean mIsLoadedFromCache;
+    private StorageCacheHelper mStorageCacheHelper;
 
     /**
      * Refresh UI for specified storageEntry.
@@ -111,14 +114,23 @@ public class StorageCategoryFragment extends DashboardFragment
             mPreferenceController.setVolume(null);
             return;
         }
+        if (mStorageCacheHelper.hasCachedSizeInfo() && mSelectedStorageEntry.isPrivate()) {
+            StorageCacheHelper.StorageCache cachedData = mStorageCacheHelper.retrieveCachedSize();
+            mPreferenceController.setVolume(mSelectedStorageEntry.getVolumeInfo());
+            mPreferenceController.setUsedSize(cachedData.usedSize);
+            mPreferenceController.setTotalSize(cachedData.totalSize);
+        }
         if (mSelectedStorageEntry.isPrivate()) {
             mStorageInfo = null;
             mAppsResult = null;
+            if (mStorageCacheHelper.hasCachedSizeInfo()) {
+                mPreferenceController.onLoadFinished(mAppsResult, mUserId);
+            } else {
                 maybeSetLoading(isQuotaSupported());
-
                 // To prevent flicker, sets null volume to hide category preferences.
                 // onReceivedSizes will setVolume with the volume of selected storage.
                 mPreferenceController.setVolume(null);
+            }
 
             // Stats data is only available on private volumes.
             getLoaderManager().restartLoader(STORAGE_JOB_ID, Bundle.EMPTY, this);
@@ -141,6 +153,15 @@ public class StorageCategoryFragment extends DashboardFragment
         }
 
         initializePreference();
+
+        if (mStorageCacheHelper.hasCachedSizeInfo()) {
+            mIsLoadedFromCache = true;
+            if (mSelectedStorageEntry != null) {
+                refreshUi(mSelectedStorageEntry);
+            }
+            updateSecondaryUserControllers(mSecondaryUsers, mAppsResult);
+            setSecondaryUsersVisible(true);
+        }
     }
 
     private void initializePreference() {
@@ -156,6 +177,7 @@ public class StorageCategoryFragment extends DashboardFragment
         mIsWorkProfile = getArguments().getInt(ProfileSelectFragment.EXTRA_PROFILE)
                 == ProfileSelectFragment.ProfileType.WORK;
         mUserId = Utils.getCurrentUserId(mUserManager, mIsWorkProfile);
+        mStorageCacheHelper = new StorageCacheHelper(getContext(), mUserId);
 
         super.onAttach(context);
     }
@@ -164,10 +186,24 @@ public class StorageCategoryFragment extends DashboardFragment
     public void onResume() {
         super.onResume();
 
+        if (mIsLoadedFromCache) {
+            mIsLoadedFromCache = false;
+        } else {
             if (mSelectedStorageEntry != null) {
                 refreshUi(mSelectedStorageEntry);
             }
         }
+    }
+
+    @Override
+    public void onPause() {
+        super.onPause();
+        // Destroy the data loaders to prevent unnecessary data loading when switching back to the
+        // page.
+        getLoaderManager().destroyLoader(STORAGE_JOB_ID);
+        getLoaderManager().destroyLoader(ICON_JOB_ID);
+        getLoaderManager().destroyLoader(VOLUME_SIZE_JOB_ID);
+    }
 
     @Override
     public void onSaveInstanceState(Bundle outState) {
@@ -188,6 +224,8 @@ public class StorageCategoryFragment extends DashboardFragment
         mPreferenceController.setVolume(mSelectedStorageEntry.getVolumeInfo());
         mPreferenceController.setUsedSize(privateUsedBytes);
         mPreferenceController.setTotalSize(mStorageInfo.totalBytes);
+        // Cache total size infor and used size info
+        mStorageCacheHelper.cacheTotalSizeAndUsedSize(mStorageInfo.totalBytes, privateUsedBytes);
         for (int i = 0, size = mSecondaryUsers.size(); i < size; i++) {
             final AbstractPreferenceController controller = mSecondaryUsers.get(i);
             if (controller instanceof SecondaryUserController) {