[Settings] Refactor Wifi Calling description text

Refactor the display of description text when no wifi calling options available.
Enhancement:
1. These text need to align the style with the summary part of the wifi
calling options.
2. These text need to be scrollable in order to see full description.
3. The link within text need to be clickable.

Bug: 204844012
Test: local
Change-Id: I60f339bf4adf50236d80176669a557c77f0d97ca
(cherry picked from commit 8a892271da)
Merged-In: I60f339bf4adf50236d80176669a557c77f0d97ca
Merged-In: I8bbe6c653c51b8ca43d936e50166f0f8bfb1acdc

res/layout/wifi_calling_settings_preferences.xml

@@ -29,16 +29,11 @@
 
     <FrameLayout
         android:id="@android:id/tabcontent"
-        android:layout_width="0dip"
-        android:layout_height="0dip" />
-
-    <FrameLayout
-        android:id="@+id/prefs_container"
         android:layout_width="match_parent"
         android:layout_height="0dip"
         android:layout_weight="1"
-        android:clipChildren="false"
+        android:clipChildren="true"
-        android:clipToPadding="false"
+        android:clipToPadding="true"
         android:smoothScrollbar="false" />
 
 </LinearLayout>

res/xml/wifi_calling_settings.xml

@@ -21,6 +21,7 @@
 
     <com.android.settings.wifi.calling.ListWithEntrySummaryPreference
             android:key="wifi_calling_mode"
+            isPreferenceVisible="false"
             android:title="@string/wifi_calling_mode_title"
             android:summary="@string/wifi_calling_mode_title"
             android:entries="@array/wifi_calling_mode_choices"
@@ -30,6 +31,7 @@
 
     <com.android.settings.wifi.calling.ListWithEntrySummaryPreference
             android:key="wifi_calling_roaming_mode"
+            isPreferenceVisible="false"
             android:title="@string/wifi_calling_roaming_mode_title"
             android:summary="@string/wifi_calling_roaming_mode_summary"
             android:entries="@array/wifi_calling_mode_choices_v2"
@@ -39,7 +41,12 @@
 
     <Preference
             android:key="emergency_address_key"
+            isPreferenceVisible="false"
             android:title="@string/emergency_address_title"
             android:summary="@string/emergency_address_summary" />
 
+    <com.android.settings.wifi.calling.LinkifyDescriptionPreference
+            android:key="no_options_description"
+            isPreferenceVisible="false" />
+
 </PreferenceScreen>

src/com/android/settings/wifi/calling/LinkifyDescriptionPreference.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2021 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.wifi.calling;
+
+import android.content.Context;
+import android.text.SpannableString;
+import android.text.TextUtils;
+import android.text.method.LinkMovementMethod;
+import android.text.style.ClickableSpan;
+import android.text.util.Linkify;
+import android.util.AttributeSet;
+import android.view.View;
+import android.widget.TextView;
+
+import androidx.core.text.util.LinkifyCompat;
+import androidx.preference.Preference;
+import androidx.preference.PreferenceViewHolder;
+
+import com.android.settings.R;
+
+/** A preference which supports linkify text as a description in the summary **/
+public class LinkifyDescriptionPreference extends Preference {
+
+    public LinkifyDescriptionPreference(Context context) {
+        this(context, null);
+    }
+
+    public LinkifyDescriptionPreference(Context context, AttributeSet attrs) {
+      super(context, attrs);
+    }
+
+    @Override
+    public void onBindViewHolder(PreferenceViewHolder holder) {
+        super.onBindViewHolder(holder);
+
+        final TextView summaryView = (TextView) holder.findViewById(android.R.id.summary);
+        if (summaryView == null || summaryView.getVisibility() != View.VISIBLE) {
+            return;
+        }
+
+        final CharSequence summary = getSummary();
+        if (TextUtils.isEmpty(summary)) {
+            return;
+        }
+
+        summaryView.setMaxLines(Integer.MAX_VALUE);
+
+        final SpannableString spannableSummary = new SpannableString(summary);
+        if (spannableSummary.getSpans(0, spannableSummary.length(), ClickableSpan.class)
+                .length > 0) {
+            summaryView.setMovementMethod(LinkMovementMethod.getInstance());
+        }
+        LinkifyCompat.addLinks(summaryView,
+                Linkify.WEB_URLS | Linkify.EMAIL_ADDRESSES | Linkify.PHONE_NUMBERS);
+    }
+}

src/com/android/settings/wifi/calling/WifiCallingSettingsForSub.java

@@ -58,8 +58,11 @@ import com.android.settings.Utils;
 import com.android.settings.core.SubSettingLauncher;
 import com.android.settings.network.ims.WifiCallingQueryImsState;
 import com.android.settings.widget.SettingsMainSwitchBar;
+import com.android.settings.wifi.calling.LinkifyDescriptionPreference;
 import com.android.settingslib.widget.OnMainSwitchChangeListener;
 
+import java.util.List;
+
 /**
  * This is the inner class of {@link WifiCallingSettings} fragment.
  * The preference screen lets you enable/disable Wi-Fi Calling and change Wi-Fi Calling mode.
@@ -73,6 +76,7 @@ public class WifiCallingSettingsForSub extends SettingsPreferenceFragment
     private static final String BUTTON_WFC_MODE = "wifi_calling_mode";
     private static final String BUTTON_WFC_ROAMING_MODE = "wifi_calling_roaming_mode";
     private static final String PREFERENCE_EMERGENCY_ADDRESS = "emergency_address_key";
+    private static final String PREFERENCE_NO_OPTIONS_DESC = "no_options_description";
 
     @VisibleForTesting
     static final int REQUEST_CHECK_WFC_EMERGENCY_ADDRESS = 1;
@@ -92,7 +96,6 @@ public class WifiCallingSettingsForSub extends SettingsPreferenceFragment
     private ListWithEntrySummaryPreference mButtonWfcMode;
     private ListWithEntrySummaryPreference mButtonWfcRoamingMode;
     private Preference mUpdateAddress;
-    private TextView mEmptyView;
 
     private boolean mValidListener = false;
     private boolean mEditableWfcMode = true;
@@ -186,14 +189,6 @@ public class WifiCallingSettingsForSub extends SettingsPreferenceFragment
     public void onActivityCreated(Bundle savedInstanceState) {
         super.onActivityCreated(savedInstanceState);
 
-        mEmptyView = getView().findViewById(android.R.id.empty);
-        setEmptyView(mEmptyView);
-        mEmptyView.setAutoLinkMask(Linkify.WEB_URLS);
-        final Resources res = getResourcesForSubId();
-        final String emptyViewText = res.getString(R.string.wifi_calling_off_explanation,
-                res.getString(R.string.wifi_calling_off_explanation_2));
-        mEmptyView.setText(emptyViewText);
-
         mSwitchBar = getView().findViewById(R.id.switch_bar);
         mSwitchBar.show();
     }
@@ -309,6 +304,9 @@ public class WifiCallingSettingsForSub extends SettingsPreferenceFragment
 
         mIntentFilter = new IntentFilter();
         mIntentFilter.addAction(ImsManager.ACTION_WFC_IMS_REGISTRATION_ERROR);
+
+        updateDescriptionForOptions(
+                List.of(mButtonWfcMode, mButtonWfcRoamingMode, mUpdateAddress));
     }
 
     @Override
@@ -324,7 +322,7 @@ public class WifiCallingSettingsForSub extends SettingsPreferenceFragment
         final View view = inflater.inflate(
                 R.layout.wifi_calling_settings_preferences, container, false);
 
-        final ViewGroup prefs_container = view.findViewById(R.id.prefs_container);
+        final ViewGroup prefs_container = view.findViewById(android.R.id.tabcontent);
         Utils.prepareCustomPreferencesList(container, view, prefs_container, false);
         final View prefs = super.onCreateView(inflater, prefs_container, savedInstanceState);
         prefs_container.addView(prefs);
@@ -573,28 +571,35 @@ public class WifiCallingSettingsForSub extends SettingsPreferenceFragment
         final PreferenceScreen preferenceScreen = getPreferenceScreen();
         final boolean updateAddressEnabled = (getCarrierActivityIntent() != null);
         if (wfcEnabled) {
-            if (mEditableWfcMode) {
-                preferenceScreen.addPreference(mButtonWfcMode);
-            } else {
             // Don't show WFC (home) preference if it's not editable.
-                preferenceScreen.removePreference(mButtonWfcMode);
+            mButtonWfcMode.setVisible(mEditableWfcMode);
-            }
-            if (mEditableWfcRoamingMode && !mUseWfcHomeModeForRoaming) {
-                preferenceScreen.addPreference(mButtonWfcRoamingMode);
-            } else {
             // Don't show WFC roaming preference if it's not editable.
-                preferenceScreen.removePreference(mButtonWfcRoamingMode);
+            mButtonWfcRoamingMode.setVisible(
-            }
+                    mEditableWfcRoamingMode && !mUseWfcHomeModeForRoaming);
-            if (updateAddressEnabled) {
+            mUpdateAddress.setVisible(updateAddressEnabled);
-                preferenceScreen.addPreference(mUpdateAddress);
         } else {
-                preferenceScreen.removePreference(mUpdateAddress);
+            mButtonWfcMode.setVisible(false);
+            mButtonWfcRoamingMode.setVisible(false);
+            mUpdateAddress.setVisible(false);
         }
-        } else {
+        updateDescriptionForOptions(
-            preferenceScreen.removePreference(mButtonWfcMode);
+                List.of(mButtonWfcMode, mButtonWfcRoamingMode, mUpdateAddress));
-            preferenceScreen.removePreference(mButtonWfcRoamingMode);
-            preferenceScreen.removePreference(mUpdateAddress);
     }
+
+    private void updateDescriptionForOptions(List<Preference> visibleOptions) {
+        LinkifyDescriptionPreference pref = findPreference(PREFERENCE_NO_OPTIONS_DESC);
+        if (pref == null) {
+            return;
+        }
+
+        boolean optionsAvailable = visibleOptions.stream().anyMatch(Preference::isVisible);
+        if (!optionsAvailable) {
+            final Resources res = getResourcesForSubId();
+            String emptyViewText = res.getString(R.string.wifi_calling_off_explanation,
+                    res.getString(R.string.wifi_calling_off_explanation_2));
+            pref.setSummary(emptyViewText);
+        }
+        pref.setVisible(!optionsAvailable);
     }
 
     @Override