Keep selected time slot and expand state when device is rotate

Bug: 187772493
Test: make SettingsRoboTests
Change-Id: If70abf06825a88f0ad0add37ef8d4f46a0aad1e9

src/com/android/settings/fuelgauge/BatteryChartPreferenceController.java

@@ -18,6 +18,7 @@ package com.android.settings.fuelgauge;
 
 import android.content.Context;
 import android.graphics.drawable.Drawable;
+import android.os.Bundle;
 import android.os.Handler;
 import android.os.Looper;
 import android.text.TextUtils;
@@ -36,8 +37,9 @@ import com.android.settings.core.PreferenceControllerMixin;
 import com.android.settingslib.core.AbstractPreferenceController;
 import com.android.settingslib.core.lifecycle.Lifecycle;
 import com.android.settingslib.core.lifecycle.LifecycleObserver;
+import com.android.settingslib.core.lifecycle.events.OnCreate;
 import com.android.settingslib.core.lifecycle.events.OnDestroy;
-import com.android.settingslib.core.lifecycle.events.OnPause;
+import com.android.settingslib.core.lifecycle.events.OnSaveInstanceState;
 import com.android.settingslib.utils.StringUtil;
 
 import java.time.Clock;
@@ -50,8 +52,9 @@ import java.util.Map;
 
 /** Controls the update for chart graph and the list items. */
 public class BatteryChartPreferenceController extends AbstractPreferenceController
-        implements PreferenceControllerMixin, LifecycleObserver, OnPause, OnDestroy,
-                BatteryChartView.OnSelectListener, ExpandDividerPreference.OnExpandListener {
+        implements PreferenceControllerMixin, LifecycleObserver, OnCreate, OnDestroy,
+                OnSaveInstanceState, BatteryChartView.OnSelectListener,
+                ExpandDividerPreference.OnExpandListener {
     private static final String TAG = "BatteryChartPreferenceController";
     /** Desired battery history size for timestamp slots. */
     public static final int DESIRED_HISTORY_SIZE = 25;
@@ -60,6 +63,10 @@ public class BatteryChartPreferenceController extends AbstractPreferenceControll
     private static final long VALID_USAGE_TIME_DURATION = DateUtils.HOUR_IN_MILLIS * 2;
     private static final long VALID_DIFF_DURATION = DateUtils.MINUTE_IN_MILLIS * 3;
 
+    // Keys for bundle instance to restore configurations.
+    private static final String KEY_EXPAND_SYSTEM_INFO = "expand_system_info";
+    private static final String KEY_CURRENT_TIME_SLOT = "current_time_slot";
+
     @VisibleForTesting
     Map<Integer, List<BatteryDiffEntry>> mBatteryIndexedMap;
 
@@ -69,6 +76,7 @@ public class BatteryChartPreferenceController extends AbstractPreferenceControll
     @VisibleForTesting BatteryChartView mBatteryChartView;
     @VisibleForTesting ExpandDividerPreference mExpandDividerPreference;
 
+    @VisibleForTesting boolean mIsExpanded = false;
     @VisibleForTesting int[] mBatteryHistoryLevels;
     @VisibleForTesting long[] mBatteryHistoryKeys;
     @VisibleForTesting int mTrapezoidIndex = BatteryChartView.SELECTED_INDEX_INVALID;
@@ -79,8 +87,6 @@ public class BatteryChartPreferenceController extends AbstractPreferenceControll
     private final Handler mHandler = new Handler(Looper.getMainLooper());
     private final CharSequence[] mNotAllowShowSummaryPackages;
 
-    private boolean mIsExpanded = false;
-
     // Preference cache to avoid create new instance each time.
     @VisibleForTesting
     final Map<String, Preference> mPreferenceCache = new HashMap<>();
@@ -103,7 +109,27 @@ public class BatteryChartPreferenceController extends AbstractPreferenceControll
     }
 
     @Override
-    public void onPause() {
+    public void onCreate(Bundle savedInstanceState) {
+        if (savedInstanceState == null) {
+            return;
+        }
+        mTrapezoidIndex =
+            savedInstanceState.getInt(KEY_CURRENT_TIME_SLOT, mTrapezoidIndex);
+        mIsExpanded =
+            savedInstanceState.getBoolean(KEY_EXPAND_SYSTEM_INFO, mIsExpanded);
+        Log.d(TAG, String.format("onCreate() slotIndex=%d isExpanded=%b",
+            mTrapezoidIndex, mIsExpanded));
+    }
+
+    @Override
+    public void onSaveInstanceState(Bundle savedInstance) {
+        if (savedInstance == null) {
+            return;
+        }
+        savedInstance.putInt(KEY_CURRENT_TIME_SLOT, mTrapezoidIndex);
+        savedInstance.putBoolean(KEY_EXPAND_SYSTEM_INFO, mIsExpanded);
+        Log.d(TAG, String.format("onSaveInstanceState() slotIndex=%d isExpanded=%b",
+            mTrapezoidIndex, mIsExpanded));
     }
 
     @Override
@@ -234,7 +260,9 @@ public class BatteryChartPreferenceController extends AbstractPreferenceControll
     }
 
     void setBatteryChartView(final BatteryChartView batteryChartView) {
-        mHandler.post(() -> setBatteryChartViewInner(batteryChartView));
+        if (mBatteryChartView != batteryChartView) {
+            mHandler.post(() -> setBatteryChartViewInner(batteryChartView));
+        }
     }
 
     private void setBatteryChartViewInner(final BatteryChartView batteryChartView) {
@@ -250,6 +278,7 @@ public class BatteryChartPreferenceController extends AbstractPreferenceControll
                 : mTrapezoidIndex;
         if (mBatteryChartView != null) {
             mBatteryChartView.setLevels(mBatteryHistoryLevels);
+            mBatteryChartView.setSelectedIndex(refreshIndex);
             setTimestampLabel();
         }
         refreshUi(refreshIndex, /*isForce=*/ true);
@@ -310,6 +339,7 @@ public class BatteryChartPreferenceController extends AbstractPreferenceControll
             if (mExpandDividerPreference == null) {
                 mExpandDividerPreference = new ExpandDividerPreference(mPrefContext);
                 mExpandDividerPreference.setOnExpandListener(this);
+                mExpandDividerPreference.setIsExpanded(mIsExpanded);
             }
             mExpandDividerPreference.setOrder(
                 mAppListPrefGroup.getPreferenceCount());

tests/robotests/src/com/android/settings/fuelgauge/BatteryChartPreferenceControllerTest.java

@@ -30,6 +30,7 @@ import android.content.Context;
 import android.content.ContentValues;
 import android.content.pm.PackageManager;
 import android.graphics.drawable.Drawable;
+import android.os.Bundle;
 import android.text.format.DateUtils;
 
 import androidx.preference.Preference;
@@ -559,6 +560,27 @@ public final class BatteryChartPreferenceControllerTest {
             .setTimestamps(any());
     }
 
+    @Test
+    public void testOnSaveInstanceState_restoreSelectedIndexAndExpandState() {
+        final int expectedIndex = 1;
+        final boolean isExpanded = true;
+        final Bundle bundle = new Bundle();
+        mBatteryChartPreferenceController.mTrapezoidIndex = expectedIndex;
+        mBatteryChartPreferenceController.mIsExpanded = isExpanded;
+        mBatteryChartPreferenceController.onSaveInstanceState(bundle);
+        // Replaces the original controller with other values.
+        mBatteryChartPreferenceController.mTrapezoidIndex = -1;
+        mBatteryChartPreferenceController.mIsExpanded = false;
+
+        mBatteryChartPreferenceController.onCreate(bundle);
+        mBatteryChartPreferenceController.setBatteryHistoryMap(
+             createBatteryHistoryMap());
+
+        assertThat(mBatteryChartPreferenceController.mTrapezoidIndex)
+            .isEqualTo(expectedIndex);
+        assertThat(mBatteryChartPreferenceController.mIsExpanded).isTrue();
+    }
+
     private static Map<Long, Map<String, BatteryHistEntry>> createBatteryHistoryMap() {
         final Map<Long, Map<String, BatteryHistEntry>> batteryHistoryMap = new HashMap<>();
         for (int index = 0; index < DESIRED_HISTORY_SIZE; index++) {