Add cache mechanism to improve icon and label loading performance

Bug: 185207505
Test: make SettingsRoboTests
Test: make SettingsGoogleRoboTests
Change-Id: I73dba5e40783f9ef4cfc0c4c33ea56b12754535d

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

@@ -255,7 +255,8 @@ public class BatteryChartView extends AppCompatImageView implements View.OnClick
     private int getTrapezoidIndex(float x) {
         for (int index = 0; index < mTrapezoidSlot.length; index++) {
             final TrapezoidSlot slot = mTrapezoidSlot[index];
-            if (x >= slot.mLeft && x <= slot.mRight) {
+            if (x >= slot.mLeft - mTrapezoidHOffset
+                    && x <= slot.mRight + mTrapezoidHOffset) {
                 return index;
             }
         }

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

@@ -26,11 +26,18 @@ import androidx.annotation.VisibleForTesting;
 
 import java.time.Duration;
 import java.util.Comparator;
+import java.util.HashMap;
+import java.util.Locale;
+import java.util.Map;
 
 /** A container class to carry battery data in a specific time slot. */
 public final class BatteryDiffEntry {
     private static final String TAG = "BatteryDiffEntry";
 
+    static Locale sCurrentLocale = null;
+    // Caches app label and icon to improve loading performance.
+    static final Map<String, BatteryEntry.NameAndIcon> sResourceCache = new HashMap<>();
+
     /** A comparator for {@link BatteryDiffEntry} based on consumed percentage. */
     public static final Comparator<BatteryDiffEntry> COMPARATOR =
             (a, b) -> Double.compare(b.getPercentOfTotal(), a.getPercentOfTotal());
@@ -97,14 +104,7 @@ public final class BatteryDiffEntry {
     /** Gets the app icon {@link Drawable} for this entry. */
     public Drawable getAppIcon() {
         loadLabelAndIcon();
-        if (mBatteryHistEntry.mConsumerType !=
-                ConvertUtils.CONSUMER_TYPE_UID_BATTERY) {
-            return mAppIcon;
-        }
-        // Returns default application icon if UID_BATTERY icon is null.
-        return mAppIcon == null
-            ? mContext.getPackageManager().getDefaultActivityIcon()
-            : mAppIcon;
+        return mAppIcon;
     }
 
     /** Gets the searching package name for UID battery type. */
@@ -140,11 +140,37 @@ public final class BatteryDiffEntry {
                 }
                 break;
             case ConvertUtils.CONSUMER_TYPE_UID_BATTERY:
+                final BatteryEntry.NameAndIcon nameAndIcon = getCache();
+                if (nameAndIcon != null) {
+                    mAppLabel = nameAndIcon.name;
+                    mAppIcon = nameAndIcon.icon;
+                    break;
+                }
                 loadNameAndIconForUid();
+                // Uses application default icon if we cannot find it from package.
+                if (mAppIcon == null) {
+                    mAppIcon = mContext.getPackageManager().getDefaultActivityIcon();
+                }
+                if (mAppLabel != null && mAppIcon != null) {
+                    sResourceCache.put(
+                        mBatteryHistEntry.getKey(),
+                        new BatteryEntry.NameAndIcon(mAppLabel, mAppIcon, /*iconId=*/ 0));
+                }
                 break;
         }
     }
 
+    private BatteryEntry.NameAndIcon getCache() {
+        final Locale locale = Locale.getDefault();
+        if (sCurrentLocale != locale) {
+            Log.d(TAG, String.format("clearCache() locale is changed from %s to %s",
+                sCurrentLocale, locale));
+            sCurrentLocale = locale;
+            clearCache();
+        }
+        return sResourceCache.get(mBatteryHistEntry.getKey());
+    }
+
     private void loadNameAndIconForUid() {
         final String packageName = mBatteryHistEntry.mPackageName;
         final PackageManager packageManager = mContext.getPackageManager();
@@ -153,7 +179,9 @@ public final class BatteryDiffEntry {
             try {
                 final ApplicationInfo appInfo =
                     packageManager.getApplicationInfo(packageName, /*no flags*/ 0);
-                mAppLabel = packageManager.getApplicationLabel(appInfo).toString();
+                if (appInfo != null) {
+                    mAppLabel = packageManager.getApplicationLabel(appInfo).toString();
+                }
             } catch (NameNotFoundException e) {
                 Log.e(TAG, "failed to retrieve ApplicationInfo for: " + packageName);
                 mAppLabel = packageName;
@@ -203,6 +231,10 @@ public final class BatteryDiffEntry {
         return builder.toString();
     }
 
+    static void clearCache() {
+        sResourceCache.clear();
+    }
+
     private static <T> T getNonNull(T originalObj, T newObj) {
         return newObj != null ? newObj : originalObj;
     }

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

@@ -65,6 +65,7 @@ public final class BatteryHistEntry {
     public final int mBatteryStatus;
     public final int mBatteryHealth;
 
+    private String mKey = null;
     private boolean mIsValidEntry = true;
 
     public BatteryHistEntry(ContentValues values) {
@@ -114,7 +115,20 @@ public final class BatteryHistEntry {
 
     /** Gets an identifier to represent this {@link BatteryHistEntry}. */
     public String getKey() {
-        return mPackageName + "-" + mUserId;
+        if (mKey == null) {
+            switch (mConsumerType) {
+                case ConvertUtils.CONSUMER_TYPE_UID_BATTERY:
+                    mKey = Long.toString(mUid);
+                    break;
+                case ConvertUtils.CONSUMER_TYPE_SYSTEM_BATTERY:
+                    mKey = "S|" + mDrainType;
+                    break;
+                case ConvertUtils.CONSUMER_TYPE_USER_BATTERY:
+                    mKey = "U|" + mUserId;
+                    break;
+            }
+        }
+        return mKey;
     }
 
     @Override