Add help info at the bottom of the dialog

It contains a link to help center

Bug: 68030013
Test: RunSettingsRoboTest
Change-Id: I79260eff35e604fa97cf21c62f58c02f3bbe5cfb

src/com/android/settings/utils/AnnotationSpan.java

@@ -0,0 +1,85 @@
+/*
+ * 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.utils;
+
+import android.text.Annotation;
+import android.text.SpannableString;
+import android.text.SpannableStringBuilder;
+import android.text.TextPaint;
+import android.text.style.URLSpan;
+import android.view.View;
+
+/**
+ * This class is used to add {@link View.OnClickListener} for the text been wrapped by
+ * annotation.
+ */
+public class AnnotationSpan extends URLSpan {
+    private final View.OnClickListener mClickListener;
+
+    private AnnotationSpan(View.OnClickListener lsn) {
+        super((String) null);
+        mClickListener = lsn;
+    }
+
+    @Override
+    public void onClick(View widget) {
+        if (mClickListener != null) {
+            mClickListener.onClick(widget);
+        }
+    }
+
+    @Override
+    public void updateDrawState(TextPaint ds) {
+        super.updateDrawState(ds);
+        ds.setUnderlineText(false);
+    }
+
+    public static CharSequence linkify(CharSequence rawText, LinkInfo... linkInfos) {
+        SpannableString msg = new SpannableString(rawText);
+        Annotation[] spans = msg.getSpans(0, msg.length(), Annotation.class);
+        SpannableStringBuilder builder = new SpannableStringBuilder(msg);
+        for (Annotation annotation : spans) {
+            final String key = annotation.getValue();
+            int start = msg.getSpanStart(annotation);
+            int end = msg.getSpanEnd(annotation);
+            AnnotationSpan link = null;
+            for (LinkInfo linkInfo : linkInfos) {
+                if (linkInfo.annotation.equals(key)) {
+                    link = new AnnotationSpan(linkInfo.listener);
+                    break;
+                }
+            }
+            if (link != null) {
+                builder.setSpan(link, start, end, msg.getSpanFlags(link));
+            }
+        }
+        return builder;
+    }
+
+    /**
+     * Data class to store the annotation and the click action
+     */
+    public static class LinkInfo {
+        public final String annotation;
+        public final View.OnClickListener listener;
+
+        public LinkInfo(String annotation, View.OnClickListener listener) {
+            this.annotation = annotation;
+            this.listener = listener;
+        }
+    }
+}