Enhance rendering performance of TextView when highlighting search results

Signed-off-by: Stefan Niedermann <info@niedermann.it>

2 files changed, 18 insertions, 8 deletions

diff --git a/markdown/src/main/java/it/niedermann/android/markdown/markwon/MarkwonMarkdownUtil.java b/markdown/src/main/java/it/niedermann/android/markdown/markwon/MarkwonMarkdownUtil.java
index d9ac64936..465aec405 100644
--- a/markdown/src/main/java/it/niedermann/android/markdown/markwon/MarkwonMarkdownUtil.java
+++ b/markdown/src/main/java/it/niedermann/android/markdown/markwon/MarkwonMarkdownUtil.java
@@ -256,7 +256,7 @@ public class MarkwonMarkdownUtil {
         return false;
     }
 
-    public static void searchAndColor(@NonNull Editable editable, @Nullable CharSequence searchText, @NonNull Context context, @Nullable Integer current, @ColorInt int mainColor) {
+    public static void searchAndColor(@NonNull Spannable editable, @Nullable CharSequence searchText, @NonNull Context context, @Nullable Integer current, @ColorInt int mainColor) {
         removeSpans(editable, SearchSpan.class);
         if (searchText != null) {
             final Matcher m = Pattern
@@ -273,9 +273,9 @@ public class MarkwonMarkdownUtil {
         }
     }
 
-    private static <T> void removeSpans(@NonNull Editable editable, @SuppressWarnings("SameParameterValue") Class<T> spanType) {
-        for (T span : editable.getSpans(0, editable.length(), spanType)) {
-            editable.removeSpan(span);
+    private static <T> void removeSpans(@NonNull Spannable spannable, @SuppressWarnings("SameParameterValue") Class<T> spanType) {
+        for (T span : spannable.getSpans(0, spannable.length(), spanType)) {
+            spannable.removeSpan(span);
         }
     }
 }
diff --git a/markdown/src/main/java/it/niedermann/android/markdown/markwon/plugins/SearchHighlightPlugin.java b/markdown/src/main/java/it/niedermann/android/markdown/markwon/plugins/SearchHighlightPlugin.java
index a12bc819e..ff144054b 100644
--- a/markdown/src/main/java/it/niedermann/android/markdown/markwon/plugins/SearchHighlightPlugin.java
+++ b/markdown/src/main/java/it/niedermann/android/markdown/markwon/plugins/SearchHighlightPlugin.java
@@ -1,8 +1,10 @@
 package it.niedermann.android.markdown.markwon.plugins;
 
 import android.content.Context;
-import android.text.Editable;
+import android.text.Spannable;
+import android.text.SpannableString;
 import android.text.SpannableStringBuilder;
+import android.util.Log;
 import android.widget.TextView;
 
 import androidx.annotation.ColorInt;
@@ -17,6 +19,8 @@ import it.niedermann.android.markdown.markwon.MarkwonMarkdownUtil;
 
 public class SearchHighlightPlugin extends AbstractMarkwonPlugin {
 
+    private static final String TAG = SearchHighlightPlugin.class.getSimpleName();
+
     private boolean searchActive = false;
     private CharSequence searchText;
     private Integer current;
@@ -47,9 +51,15 @@ public class SearchHighlightPlugin extends AbstractMarkwonPlugin {
     public void afterSetText(@NonNull TextView textView) {
         super.afterSetText(textView);
         if (this.searchActive) {
-            final Editable coloredContent = new SpannableStringBuilder(textView.getText());
-            MarkwonMarkdownUtil.searchAndColor(coloredContent, searchText, textView.getContext(), current, color);
-            textView.setText(coloredContent, TextView.BufferType.SPANNABLE);
+            final CharSequence content = textView.getText();
+            if (content.getClass() == SpannableString.class || content instanceof Spannable) {
+                MarkwonMarkdownUtil.searchAndColor((Spannable) content, searchText, textView.getContext(), current, color);
+            } else {
+                Log.w(TAG, "Expected " + TextView.class.getSimpleName() + " content to be of type " + Spannable.class.getSimpleName() + ", but was of type " + content.getClass() + ". Search highlighting will be not performant.");
+                final Spannable coloredContent = new SpannableStringBuilder(content);
+                textView.setText(coloredContent, TextView.BufferType.SPANNABLE);
+                MarkwonMarkdownUtil.searchAndColor(coloredContent, searchText, textView.getContext(), current, color);
+            }
         }
     }
 }