Fix b/265364351: Light theme icons opacity is too light

https://screenshot.googleplex.com/Avqsw3gb2tjKqrK.png
https://screenshot.googleplex.com/46AZuJMjp2HMyqd.png
https://screenshot.googleplex.com/9mE3XutRUNaGckg.png
https://screenshot.googleplex.com/5rNUKMJjhNBNShZ.png

Bug: 265364351
Fix: 265364351
Test: manual
Change-Id: I7521030f1a5d84cd88027fb84a465623610707fb

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

@@ -20,7 +20,6 @@ import android.animation.Animator;
 import android.animation.AnimatorListenerAdapter;
 import android.app.settings.SettingsEnums;
 import android.content.Context;
-import android.content.res.Configuration;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Looper;
@@ -68,8 +67,6 @@ public class BatteryChartPreferenceController extends AbstractPreferenceControll
     private static final String KEY_DAILY_CHART_INDEX = "daily_chart_index";
     private static final String KEY_HOURLY_CHART_INDEX = "hourly_chart_index";
 
-    private static int sUiMode = Configuration.UI_MODE_NIGHT_UNDEFINED;
-
     /**
      * A callback listener for battery usage is updated.
      * This happens when battery usage data is ready or the selected index is changed.
@@ -167,14 +164,6 @@ public class BatteryChartPreferenceController extends AbstractPreferenceControll
 
     @Override
     public void onResume() {
-        final int currentUiMode =
-                mContext.getResources().getConfiguration().uiMode
-                        & Configuration.UI_MODE_NIGHT_MASK;
-        if (sUiMode != currentUiMode) {
-            sUiMode = currentUiMode;
-            BatteryDiffEntry.clearCache();
-            Log.d(TAG, "clear icon and label cache since uiMode is changed");
-        }
         mIs24HourFormat = DateFormat.is24HourFormat(mContext);
         mMetricsFeatureProvider.action(mPrefContext, SettingsEnums.OPEN_BATTERY_USAGE);
     }

src/com/android/settings/fuelgauge/batteryusage/BatteryUsageBreakdownController.java

@@ -18,6 +18,7 @@ package com.android.settings.fuelgauge.batteryusage;
 
 import android.app.settings.SettingsEnums;
 import android.content.Context;
+import android.content.res.Configuration;
 import android.graphics.drawable.Drawable;
 import android.os.Handler;
 import android.os.Looper;
@@ -43,6 +44,7 @@ import com.android.settingslib.core.instrumentation.MetricsFeatureProvider;
 import com.android.settingslib.core.lifecycle.Lifecycle;
 import com.android.settingslib.core.lifecycle.LifecycleObserver;
 import com.android.settingslib.core.lifecycle.events.OnDestroy;
+import com.android.settingslib.core.lifecycle.events.OnResume;
 import com.android.settingslib.widget.FooterPreference;
 
 import java.util.HashMap;
@@ -51,15 +53,15 @@ import java.util.Map;
 
 /** Controller for battery usage breakdown preference group. */
 public class BatteryUsageBreakdownController extends BasePreferenceController
-        implements LifecycleObserver, OnDestroy  {
+        implements LifecycleObserver, OnResume, OnDestroy  {
     private static final String TAG = "BatteryUsageBreakdownController";
     private static final String ROOT_PREFERENCE_KEY = "battery_usage_breakdown";
     private static final String FOOTER_PREFERENCE_KEY = "battery_usage_footer";
     private static final String SPINNER_PREFERENCE_KEY = "battery_usage_spinner";
     private static final String APP_LIST_PREFERENCE_KEY = "app_list";
     private static final String PACKAGE_NAME_NONE = "none";
-    private static final int ENABLED_ICON_ALPHA = 255;
-    private static final int DISABLED_ICON_ALPHA = 255 / 3;
+
+    private static int sUiMode = Configuration.UI_MODE_NIGHT_UNDEFINED;
 
     private final SettingsActivity mActivity;
     private final InstrumentedPreferenceFragment mFragment;
@@ -98,6 +100,19 @@ public class BatteryUsageBreakdownController extends BasePreferenceController
         }
     }
 
+    @Override
+    public void onResume() {
+        final int currentUiMode =
+                mContext.getResources().getConfiguration().uiMode
+                        & Configuration.UI_MODE_NIGHT_MASK;
+        if (sUiMode != currentUiMode) {
+            sUiMode = currentUiMode;
+            BatteryDiffEntry.clearCache();
+            mPreferenceCache.clear();
+            Log.d(TAG, "clear icon and label cache since uiMode is changed");
+        }
+    }
+
     @Override
     public void onDestroy() {
         mHandler.removeCallbacksAndMessages(/*token=*/ null);
@@ -273,12 +288,11 @@ public class BatteryUsageBreakdownController extends BasePreferenceController
             pref.setSingleLineTitle(true);
             // Sets the BatteryDiffEntry to preference for launching detailed page.
             pref.setBatteryDiffEntry(entry);
-            pref.setEnabled(entry.validForRestriction());
+            pref.setSelectable(entry.validForRestriction());
             setPreferenceSummary(pref, entry);
             if (!isAdded) {
                 mAppListPreferenceGroup.addPreference(pref);
             }
-            appIcon.setAlpha(pref.isEnabled() ? ENABLED_ICON_ALPHA : DISABLED_ICON_ALPHA);
             prefIndex++;
         }
         Log.d(TAG, String.format("addAllPreferences() is finished in %d/ms",

src/com/android/settings/fuelgauge/batteryusage/PowerGaugePreference.java

@@ -19,6 +19,8 @@ package com.android.settings.fuelgauge.batteryusage;
 import android.content.Context;
 import android.graphics.drawable.Drawable;
 import android.util.AttributeSet;
+import android.view.View;
+import android.view.ViewGroup;
 import android.widget.TextView;
 
 import androidx.preference.PreferenceViewHolder;
@@ -37,6 +39,10 @@ import com.android.settingslib.widget.AppPreference;
 public class PowerGaugePreference extends AppPreference {
 
     private static final double PERCENTAGE_TO_SHOW_THRESHOLD = 1f;
+    // Please see go/battery-usage-app-list-alpha
+    private static final float SELECTABLE_ALPHA = 1f;
+    private static final float UNSELECTABLE_ALPHA_LIGHT_MODE = 0.65f;
+    private static final float UNSELECTABLE_ALPHA_DARK_MODE = 0.5f;
 
     private BatteryEntry mInfo;
     private BatteryDiffEntry mBatteryDiffEntry;
@@ -125,6 +131,11 @@ public class PowerGaugePreference extends AppPreference {
     public void onBindViewHolder(PreferenceViewHolder view) {
         super.onBindViewHolder(view);
 
+        final boolean isNightMode = Utils.isNightMode(getContext());
+        final float alpha = isSelectable() ? SELECTABLE_ALPHA
+                : (isNightMode ? UNSELECTABLE_ALPHA_DARK_MODE : UNSELECTABLE_ALPHA_LIGHT_MODE);
+        setViewAlpha(view.itemView, alpha);
+
         final TextView subtitle = (TextView) view.findViewById(R.id.widget_summary);
         subtitle.setText(mProgress);
         if (mShowAnomalyIcon) {
@@ -138,4 +149,15 @@ public class PowerGaugePreference extends AppPreference {
             titleView.setContentDescription(mContentDescription);
         }
     }
+
+    private static void setViewAlpha(View view, float alpha) {
+        if (view instanceof ViewGroup) {
+            final ViewGroup viewGroup = (ViewGroup) view;
+            for (int i = viewGroup.getChildCount() - 1; i >= 0; i--) {
+                setViewAlpha(viewGroup.getChildAt(i), alpha);
+            }
+        } else {
+            view.setAlpha(alpha);
+        }
+    }
 }

tests/robotests/src/com/android/settings/fuelgauge/batteryusage/BatteryUsageBreakdownControllerTest.java

@@ -157,7 +157,7 @@ public final class BatteryUsageBreakdownControllerTest {
         assertThat(pref.getOrder()).isEqualTo(1);
         assertThat(pref.getBatteryDiffEntry()).isSameInstanceAs(mBatteryDiffEntry);
         assertThat(pref.isSingleLineTitle()).isTrue();
-        assertThat(pref.isEnabled()).isFalse();
+        assertThat(pref.isSelectable()).isFalse();
     }
 
     @Test