Refactor IMEAndLanguageSettings to use PreferenceController

Bug: 32642706
Bug: 32637613
Bug: 32643833
Test: RunSettingsRoboTests

This change is necessary to test preference controlling logic, as well
as making preferences reusable in other Preference pages in the new
information architecture.

Change-Id: I9e2fd2f6800579f005a5c303ed03ae06477006a6

src/com/android/settings/language/UserDictionaryPreferenceController.java

@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2016 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.language;
+
+import android.app.Fragment;
+import android.content.Context;
+import android.os.Bundle;
+import android.support.v7.preference.Preference;
+
+import com.android.settings.UserDictionarySettings;
+import com.android.settings.core.PreferenceController;
+import com.android.settings.inputmethod.UserDictionaryList;
+
+import java.util.TreeSet;
+
+public class UserDictionaryPreferenceController extends PreferenceController {
+
+    private static final String KEY_USER_DICTIONARY_SETTINGS = "key_user_dictionary_settings";
+
+    public UserDictionaryPreferenceController(Context context) {
+        super(context);
+    }
+
+    @Override
+    public boolean isAvailable() {
+        final TreeSet<String> localeSet = getDictionaryLocales();
+        // The locale list is null if and only if the user dictionary service is
+        // not present or disabled. In this case we need to remove the preference.
+        return localeSet != null;
+    }
+
+    @Override
+    public boolean handlePreferenceTreeClick(Preference preference) {
+        return false;
+    }
+
+    @Override
+    public String getPreferenceKey() {
+        return KEY_USER_DICTIONARY_SETTINGS;
+    }
+
+    @Override
+    public void updateState(Preference preference) {
+        if (!isAvailable() || preference == null) {
+            return;
+        }
+        final TreeSet<String> localeSet = getDictionaryLocales();
+        final Bundle extras = preference.getExtras();
+        final Class<? extends Fragment> targetFragment;
+        if (localeSet.size() <= 1) {
+            if (!localeSet.isEmpty()) {
+                // If the size of localeList is 0, we don't set the locale
+                // parameter in the extras. This will be interpreted by the
+                // UserDictionarySettings class as meaning
+                // "the current locale". Note that with the current code for
+                // UserDictionaryList#getUserDictionaryLocalesSet()
+                // the locale list always has at least one element, since it
+                // always includes the current locale explicitly.
+                // @see UserDictionaryList.getUserDictionaryLocalesSet().
+                extras.putString("locale", localeSet.first());
+            }
+            targetFragment = UserDictionarySettings.class;
+        } else {
+            targetFragment = UserDictionaryList.class;
+        }
+        preference.setFragment(targetFragment.getCanonicalName());
+    }
+
+    protected TreeSet<String> getDictionaryLocales() {
+        return UserDictionaryList.getUserDictionaryLocalesSet(mContext);
+    }
+}