Add support for multi-line strings to SpannedToHtmlConverter

PiperOrigin-RevId: 304355717

library/ui/src/main/java/com/google/android/exoplayer2/ui/SpannedToHtmlConverter.java

@@ -33,6 +33,7 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
+import java.util.regex.Pattern;
 
 /**
  * Utility class to convert from <a
@@ -44,6 +45,9 @@ import java.util.List;
 // TODO: Add support for more span types - only a small selection are currently implemented.
 /* package */ final class SpannedToHtmlConverter {
 
+  // Matches /n and /r/n in ampersand-encoding (returned from Html.escapeHtml).
+  private static final Pattern NEWLINE_PATTERN = Pattern.compile("(&#13;)?&#10;");
+
   private SpannedToHtmlConverter() {}
 
   /**
@@ -67,7 +71,7 @@ import java.util.List;
       return "";
     }
     if (!(text instanceof Spanned)) {
-      return Html.escapeHtml(text);
+      return escapeHtml(text);
     }
     Spanned spanned = (Spanned) text;
     SparseArray<Transition> spanTransitions = findSpanTransitions(spanned);
@@ -76,7 +80,7 @@ import java.util.List;
     int previousTransition = 0;
     for (int i = 0; i < spanTransitions.size(); i++) {
       int index = spanTransitions.keyAt(i);
-      html.append(Html.escapeHtml(spanned.subSequence(previousTransition, index)));
+      html.append(escapeHtml(spanned.subSequence(previousTransition, index)));
 
       Transition transition = spanTransitions.get(index);
       Collections.sort(transition.spansRemoved, SpanInfo.FOR_CLOSING_TAGS);
@@ -90,7 +94,7 @@ import java.util.List;
       previousTransition = index;
     }
 
-    html.append(Html.escapeHtml(spanned.subSequence(previousTransition, spanned.length())));
+    html.append(escapeHtml(spanned.subSequence(previousTransition, spanned.length())));
 
     return html.toString();
   }
@@ -187,6 +191,11 @@ import java.util.List;
     return transition;
   }
 
+  private static String escapeHtml(CharSequence text) {
+    String escaped = Html.escapeHtml(text);
+    return NEWLINE_PATTERN.matcher(escaped).replaceAll("<br>");
+  }
+
   private static final class SpanInfo {
     /**
      * Sort by end index (descending), then by opening tag and then closing tag (both ascending, for

library/ui/src/test/java/com/google/android/exoplayer2/ui/SpannedToHtmlConverterTest.java

@@ -133,6 +133,20 @@ public class SpannedToHtmlConverterTest {
   }
 
   @Test
+  public void convert_handlesLinebreakInUnspannedString() {
+    String html = SpannedToHtmlConverter.convert("String with\nnew line and\r\ncrlf style too");
+
+    assertThat(html).isEqualTo("String with<br>new line and<br>crlf style too");
+  }
+
+  @Test
+  public void convert_doesntConvertAmpersandLineFeedToBrTag() {
+    String html = SpannedToHtmlConverter.convert("String with&#10;new line ampersand code");
+
+    assertThat(html).isEqualTo("String with&amp;#10;new line ampersand code");
+  }
+
+  @Test
   public void convert_escapesUnrecognisedTagInSpannedString() {
     SpannableString spanned = new SpannableString("String with <foo>unrecognised</foo> tags");
     spanned.setSpan(
@@ -147,6 +161,13 @@ public class SpannedToHtmlConverterTest {
   }
 
   @Test
+  public void convert_handlesLinebreakInSpannedString() {
+    String html = SpannedToHtmlConverter.convert("String with\nnew line and\r\ncrlf style too");
+
+    assertThat(html).isEqualTo("String with<br>new line and<br>crlf style too");
+  }
+
+  @Test
   public void convert_convertsNonAsciiCharactersToAmpersandCodes() {
     String html =
         SpannedToHtmlConverter.convert(