Fix voice access problem on location page.

- Remove the seletcable attribute on footer preference so that
voice access can identify learn more.
- Apply latest footer preference API to set an action on learn more.
- Remove unuse string resource.

Test: Verify that talkback and voice access work well.
Fix: 189652942
Change-Id: I45fcd21d6a2d693d8b5eaa446aaccb769f1c0c7f

res/values/strings.xml

@@ -695,9 +695,8 @@
         emergency responders when you call or text an emergency number.
     </string>
     <!-- Location settings footer link to support page [CHAR LIMIT=NONE] -->
-    <string name="location_settings_footer_learn_more">
-        &lt;a href="<xliff:g example="http://www.google.com"
-        id="url"> https://support.google.com/android/answer/3467281</xliff:g>">Learn more&lt;/a>
+    <string name="location_settings_footer_learn_more_link" translatable="false">
+        https://support.google.com/android/answer/3467281
     </string>
     <!-- Location settings footer link content description [CHAR LIMIT=NONE] -->
     <string name="location_settings_footer_learn_more_content_description">

res/xml/location_settings.xml

@@ -71,7 +71,6 @@
     <com.android.settingslib.widget.FooterPreference
         android:title="@string/location_settings_footer_general"
         android:key="location_footer"
-        android:selectable="false"
         settings:searchable="false"
         settings:controller="com.android.settings.location.LocationSettingsFooterPreferenceController"/>
 </PreferenceScreen>

src/com/android/settings/location/LocationSettingsFooterPreferenceController.java

@@ -31,6 +31,7 @@ import androidx.preference.Preference;
 import androidx.preference.PreferenceScreen;
 
 import com.android.settings.R;
+import com.android.settingslib.HelpUtils;
 import com.android.settingslib.widget.FooterPreference;
 
 import java.util.ArrayList;
@@ -104,15 +105,22 @@ public class LocationSettingsFooterPreferenceController extends LocationBasePref
                     + footerString;
         }
         if (mFooterPreference != null) {
-            mFooterPreference.setTitle(Html.fromHtml(footerString
-                    + PARAGRAPH_SEPARATOR
-                    + mContext.getString(
-                    R.string.location_settings_footer_learn_more)));
-            mFooterPreference.setContentDescription(Html.fromHtml(footerString + mContext.getString(
-                    R.string.location_settings_footer_learn_more_content_description)));
+            mFooterPreference.setTitle(Html.fromHtml(footerString));
+            mFooterPreference.setLearnMoreAction(v -> openLocationLearnMoreLink());
+            mFooterPreference.setLearnMoreContentDescription(mContext.getString(
+                    R.string.location_settings_footer_learn_more_content_description));
         }
     }
 
+    private void openLocationLearnMoreLink() {
+        mFragment.startActivityForResult(
+                HelpUtils.getHelpIntent(
+                        mContext,
+                        mContext.getString(R.string.location_settings_footer_learn_more_link),
+                        /*backupContext=*/""),
+                /*requestCode=*/ 0);
+    }
+
     /**
      * Location footer preference group should always be displayed.
      */