Extract UserShortcutType functions from ToggleFeaturePreferenceFragment

* Simplify StringJoiner to '+' since it only have one case
* Simplify Collections usage to use removeIf() and findFirst() directly
* Change class name SharedPreferenceUtils to PreferredShortcuts

Bug: 158540780
Test: atest ToggleFeaturePreferenceFragmentTest
Test: atest PreferredShortcutsTest
Change-Id: I02f03ccba09b6d7edaa5c0c8223ab3561a5e976b

src/com/android/settings/accessibility/PreferredShortcuts.java

@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.accessibility;
+
+import android.content.ComponentName;
+import android.content.Context;
+import android.content.SharedPreferences;
+
+import com.android.settings.accessibility.AccessibilityUtil.UserShortcutType;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/** Static utility methods relating to {@link PreferredShortcut} */
+public final class PreferredShortcuts {
+
+    private static final String ACCESSIBILITY_PERF = "accessibility_prefs";
+    private static final String USER_SHORTCUT_TYPE = "user_shortcut_type";
+
+    /**
+     * Retrieves {@link UserShortcutType} for the given {@code componentName} from
+     * SharedPreferences.
+     *
+     * @param context       {@link Context} to access the {@link SharedPreferences}
+     * @param componentName Name of the service or activity, should be the format of {@link
+     *                      ComponentName#flattenToString()}.
+     * @param defaultType   See {@link UserShortcutType}
+     * @return {@link UserShortcutType}
+     */
+    public static int retrieveUserShortcutType(Context context, String componentName,
+            int defaultType) {
+        if (componentName == null) {
+            return defaultType;
+        }
+
+        // Create a mutable set to modify
+        final Set<String> info = new HashSet<>(getFromSharedPreferences(context));
+        info.removeIf(str -> !str.contains(componentName));
+
+        if (info.isEmpty()) {
+            return defaultType;
+        }
+
+        final String str = info.stream().findFirst().get();
+        final PreferredShortcut shortcut = PreferredShortcut.fromString(str);
+        return shortcut.getType();
+    }
+
+    /**
+     * Saves a {@link PreferredShortcut} which containing {@link ComponentName#flattenToString()}
+     * and {@link UserShortcutType} in SharedPreferences.
+     *
+     * @param context  {@link Context} to access the {@link SharedPreferences}
+     * @param shortcut Contains {@link ComponentName#flattenToString()} and {@link UserShortcutType}
+     */
+    public static void saveUserShortcutType(Context context, PreferredShortcut shortcut) {
+        final String componentName = shortcut.getComponentName();
+        if (componentName == null) {
+            return;
+        }
+
+        // Create a mutable set to modify
+        final Set<String> info = new HashSet<>(getFromSharedPreferences(context));
+        info.removeIf(str -> str.contains(componentName));
+        info.add(shortcut.toString());
+        saveToSharedPreferences(context, info);
+    }
+
+    /**
+     * Returns a immutable set of {@link PreferredShortcut#toString()} list from
+     * SharedPreferences.
+     */
+    private static Set<String> getFromSharedPreferences(Context context) {
+        return getSharedPreferences(context).getStringSet(USER_SHORTCUT_TYPE, Set.of());
+    }
+
+    /** Sets a set of {@link PreferredShortcut#toString()} list into SharedPreferences. */
+    private static void saveToSharedPreferences(Context context, Set<String> data) {
+        SharedPreferences.Editor editor = getSharedPreferences(context).edit();
+        editor.putStringSet(USER_SHORTCUT_TYPE, data).apply();
+    }
+
+    private static SharedPreferences getSharedPreferences(Context context) {
+        return context.getSharedPreferences(ACCESSIBILITY_PERF, Context.MODE_PRIVATE);
+    }
+
+    private PreferredShortcuts() {}
+}