New time zone picker page

- Show current selected region and time zone in a 2 rows.
  Defailed info of current selected time zone in footer
- Show option menu to switch to select UTC offset
- This picker will be changed to the default picker in a later CL

Bug: 73952488
Test: m RunSettingsRoboTests
Change-Id: Ia81bb022e1021369612f5bd60c2c1f4d08db2af8
(cherry picked from commit b7d588f341)

src/com/android/settings/datetime/timezone/TimeZoneInfoPreferenceController.java

@@ -0,0 +1,137 @@
+/*
+ * Copyright (C) 2018 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.datetime.timezone;
+
+import android.content.Context;
+import android.icu.impl.OlsonTimeZone;
+import android.icu.text.DateFormat;
+import android.icu.text.DisplayContext;
+import android.icu.text.SimpleDateFormat;
+import android.icu.util.Calendar;
+import android.icu.util.TimeZone;
+import android.icu.util.TimeZoneTransition;
+import android.support.annotation.VisibleForTesting;
+import android.support.v7.preference.Preference;
+
+import com.android.settings.R;
+import com.android.settingslib.widget.FooterPreference;
+
+import java.util.Date;
+
+public class TimeZoneInfoPreferenceController extends BaseTimeZonePreferenceController {
+    private static final String PREFERENCE_KEY = FooterPreference.KEY_FOOTER;
+
+    private TimeZoneInfo mTimeZoneInfo;
+    private final DateFormat mDateFormat;
+    private final Date mDate;
+
+    public TimeZoneInfoPreferenceController(Context context) {
+        this(context, new Date());
+    }
+
+    @VisibleForTesting
+    TimeZoneInfoPreferenceController(Context context, Date date) {
+        super(context, PREFERENCE_KEY);
+        mDateFormat = DateFormat.getDateInstance(SimpleDateFormat.LONG);
+        mDateFormat.setContext(DisplayContext.CAPITALIZATION_NONE);
+        mDate = date;
+    }
+
+    @Override
+    public int getAvailabilityStatus() {
+        return AVAILABLE;
+    }
+
+    @Override
+    public void updateState(Preference preference) {
+        CharSequence formattedTimeZone = mTimeZoneInfo == null ? "" : formatInfo(mTimeZoneInfo);
+        preference.setTitle(formattedTimeZone);
+        preference.setVisible(mTimeZoneInfo != null);
+    }
+
+    public void setTimeZoneInfo(TimeZoneInfo timeZoneInfo) {
+        mTimeZoneInfo = timeZoneInfo;
+    }
+
+    public TimeZoneInfo getTimeZoneInfo() {
+        return mTimeZoneInfo;
+    }
+
+    private CharSequence formatOffsetAndName(TimeZoneInfo item) {
+        String name = item.getGenericName();
+        if (name == null) {
+            if (item.getTimeZone().inDaylightTime(mDate)) {
+                name = item.getDaylightName();
+            } else {
+                name = item.getStandardName();
+            }
+        }
+        if (name == null) {
+            return item.getGmtOffset().toString();
+        } else {
+            return SpannableUtil.getResourcesText(mContext.getResources(),
+                    R.string.zone_info_offset_and_name, item.getGmtOffset(),
+                    name);
+        }
+    }
+
+    private CharSequence formatInfo(TimeZoneInfo item) {
+        final CharSequence offsetAndName = formatOffsetAndName(item);
+        final TimeZone timeZone = item.getTimeZone();
+        if (!timeZone.observesDaylightTime()) {
+            return mContext.getString(R.string.zone_info_footer_no_dst, offsetAndName);
+        }
+
+        final TimeZoneTransition nextDstTransition = findNextDstTransition(timeZone);
+        if (nextDstTransition == null) {
+            return null;
+        }
+        final boolean toDst = nextDstTransition.getTo().getDSTSavings() != 0;
+        String timeType = toDst ? item.getDaylightName() : item.getStandardName();
+        if (timeType == null) {
+            // Fall back to generic "summer time" and "standard time" if the time zone has no
+            // specific names.
+            timeType = toDst ?
+                    mContext.getString(R.string.zone_time_type_dst) :
+                    mContext.getString(R.string.zone_time_type_standard);
+
+        }
+        final Calendar transitionTime = Calendar.getInstance(timeZone);
+        transitionTime.setTimeInMillis(nextDstTransition.getTime());
+        final String date = mDateFormat.format(transitionTime);
+        return SpannableUtil.getResourcesText(mContext.getResources(),
+                R.string.zone_info_footer, offsetAndName, timeType, date);
+    }
+
+    private TimeZoneTransition findNextDstTransition(TimeZone timeZone) {
+        if (!(timeZone instanceof OlsonTimeZone)) {
+            return null;
+        }
+        final OlsonTimeZone olsonTimeZone = (OlsonTimeZone) timeZone;
+        TimeZoneTransition transition = olsonTimeZone.getNextTransition(
+                mDate.getTime(), /* inclusive */ false);
+        do {
+            if (transition.getTo().getDSTSavings() != transition.getFrom().getDSTSavings()) {
+                break;
+            }
+            transition = olsonTimeZone.getNextTransition(
+                    transition.getTime(), /*inclusive */ false);
+        } while (transition != null);
+        return transition;
+    }
+
+}