Trim message bodies at display time.

app/src/main/java/org/thoughtcrime/securesms/conversation/ConversationItem.java

@@ -115,6 +115,7 @@ import org.thoughtcrime.securesms.util.InterceptableLongClickCopyLinkSpan;
 import org.thoughtcrime.securesms.util.LongClickMovementMethod;
 import org.thoughtcrime.securesms.util.MessageRecordUtil;
 import org.thoughtcrime.securesms.util.SearchUtil;
+import org.thoughtcrime.securesms.util.StringUtil;
 import org.thoughtcrime.securesms.util.TextSecurePreferences;
 import org.thoughtcrime.securesms.util.ThemeUtil;
 import org.thoughtcrime.securesms.util.UrlClickHandler;
@@ -642,7 +643,7 @@ public class ConversationItem extends LinearLayout implements BindableConversati
         bodyText.setMentionBackgroundTint(ContextCompat.getColor(context, R.color.transparent_black_40));
       }
 
-      bodyText.setText(styledText);
+      bodyText.setText(StringUtil.trim(styledText));
       bodyText.setVisibility(View.VISIBLE);
     }
   }

app/src/main/java/org/thoughtcrime/securesms/util/StringUtil.java

@@ -59,6 +59,33 @@ public final class StringUtil {
     return name;
   }
 
+  /**
+   * @return A charsequence with no leading or trailing whitespace. Only creates a new charsequence
+   *         if it has to.
+   */
+  public static @NonNull CharSequence trim(@NonNull CharSequence charSequence) {
+    if (charSequence.length() == 0) {
+      return charSequence;
+    }
+
+    int start = 0;
+    int end   = charSequence.length() - 1;
+
+    while (start < charSequence.length() && Character.isWhitespace(charSequence.charAt(start))) {
+      start++;
+    }
+
+    while (end >= 0 && end > start && Character.isWhitespace(charSequence.charAt(end))) {
+      end--;
+    }
+
+    if (start > 0 || end < charSequence.length() - 1) {
+      return charSequence.subSequence(start, end + 1);
+    } else {
+      return charSequence;
+    }
+  }
+
   /**
    * @return True if the string is empty, or if it contains nothing but whitespace characters.
    *         Accounts for various unicode whitespace characters.

app/src/test/java/org/thoughtcrime/securesms/util/StringUtilTest_trim.java

@@ -0,0 +1,59 @@
+package org.thoughtcrime.securesms.util;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+
+import java.util.Arrays;
+import java.util.Collection;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotSame;
+import static org.junit.Assert.assertSame;
+
+@RunWith(Parameterized.class)
+public final class StringUtilTest_trim {
+
+  private final CharSequence input;
+  private final CharSequence expected;
+  private final boolean      changed;
+
+  @Parameterized.Parameters
+  public static Collection<Object[]> data() {
+    return Arrays.asList(new Object[][]{
+      { "",        "",       false },
+      { " ",       "",       true },
+      { "   ",     "",       true },
+      { "\n",      "",       true},
+      { "\n\n\n",  "",       true },
+      { "A",       "A",      false },
+      { "A ",      "A",      true },
+      { " A",      "A",      true },
+      { " A ",     "A",      true },
+      { "\nA\n",   "A",      true },
+      { "A\n\n",   "A",      true },
+      { "A\n\nB",  "A\n\nB", false },
+      { "A\n\nB ", "A\n\nB", true },
+      { "A  B",    "A  B",   false },
+    });
+  }
+
+  public StringUtilTest_trim(CharSequence input, CharSequence expected, boolean changed) {
+    this.input    = input;
+    this.expected = expected;
+    this.changed  = changed;
+  }
+
+  @Test
+  public void trim() {
+    CharSequence output = StringUtil.trim(input);
+    assertEquals(expected, output);
+
+    if (changed) {
+      assertNotSame(output, input);
+    } else {
+      assertSame(output, input);
+    }
+  }
+
+}