Update view alpha to improve text color constract in Battery usage

- For light themes, first set the text color of title/summary/widget_summary to be consistent, then apply alpha = 0.65

[Before] https://screenshot.googleplex.com/4nVMMFBK7odhQju
A11y Scanner result: https://screenshot.googleplex.com/4nVMMFBK7odhQju

[After] https://screenshot.googleplex.com/B4r79v89HnWr4tw
A11y Scanner result: https://screenshot.googleplex.com/3zQfRMe4HToc8Xm

Dark mode:
[before] https://screenshot.googleplex.com/BfLxR6tqQRgP4mQ
[after]  https://screenshot.googleplex.com/8KeG62i7R5hW8Ks

Bug: 317139415
Bug: 265364351
Test: Accessibility Scanner
Change-Id: I65a71525bbce41c37ee364f3f73c0d2d1d9ace38

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

@@ -44,6 +44,8 @@ public class PowerGaugePreference extends AppPreference {
     private static final float UNSELECTABLE_ALPHA_LIGHT_MODE = 0.65f;
     private static final float UNSELECTABLE_ALPHA_DARK_MODE = 0.65f;
 
+    private final int mTitleColorNormal;
+
     private BatteryEntry mInfo;
     private BatteryDiffEntry mBatteryDiffEntry;
     private CharSequence mContentDescription;
@@ -78,6 +80,8 @@ public class PowerGaugePreference extends AppPreference {
         mInfo = info;
         mContentDescription = contentDescription;
         mShowAnomalyIcon = false;
+        mTitleColorNormal =
+                Utils.getColorAttrDefaultColor(context, android.R.attr.textColorPrimary);
     }
 
     /** Sets the content description. */
@@ -155,6 +159,13 @@ public class PowerGaugePreference extends AppPreference {
             final TextView titleView = (TextView) view.findViewById(android.R.id.title);
             titleView.setContentDescription(mContentDescription);
         }
+
+        if (!isSelectable()) {
+            // Set colors consistently to meet contrast requirements for non-selectable items
+            ((TextView) view.findViewById(android.R.id.title)).setTextColor(mTitleColorNormal);
+            ((TextView) view.findViewById(android.R.id.summary)).setTextColor(mTitleColorNormal);
+            subtitle.setTextColor(mTitleColorNormal);
+        }
     }
 
     private static void setViewAlpha(View view, float alpha) {