Markdown check box in view mode

app/src/main/java/net/gsantner/markor/activity/DocumentEditAndViewFragment.java

@@ -1261,9 +1261,13 @@ public void setViewModeVisibility(boolean show, final boolean animate) {
     @JavascriptInterface
     public void webViewJavascriptCallback(final String[] jsArgs) {
         final String[] args = (jsArgs == null || jsArgs.length == 0 || jsArgs[0] == null) ? new String[0] : jsArgs;
-        final String type = args.length == 0 || TextUtils.isEmpty(args[0]) ? "" : args[0];
-        if (type.equalsIgnoreCase("toast") && args.length == 2) {
-            Toast.makeText(getActivity(), args[1], Toast.LENGTH_SHORT).show();
+        final Activity activity = getActivity();
+        if (activity != null) {
+            activity.runOnUiThread(() -> {
+                if (_format != null) {
+                    _format.getActions().onWebViewJavascriptCallback(args);
+                }
+            });
         }
     }
 

app/src/main/java/net/gsantner/markor/format/ActionButtonBase.java

@@ -27,6 +27,7 @@
 import android.webkit.WebView;
 import android.widget.EditText;
 import android.widget.ImageView;
+import android.widget.Toast;
 
 import androidx.annotation.DrawableRes;
 import androidx.annotation.NonNull;
@@ -105,6 +106,13 @@ public boolean onActionLongClick(final @StringRes int action) {
         return runCommonLongPressAction(action);
     }
 
+    // Override to implement custom callbacks from view-mode JavaScript
+    public void onWebViewJavascriptCallback(final String[] args) {
+        if (args.length == 2 && "toast".equalsIgnoreCase(args[0]) && _activity != null) {
+            Toast.makeText(_activity, args[1], Toast.LENGTH_SHORT).show();
+        }
+    }
+
     private TextSearchViewHolder _textSearchViewHolder;
 
     public ActionButtonBase initTextSearch(DocumentEditAndViewFragment fragment) {

app/src/main/java/net/gsantner/markor/format/markdown/MarkdownActionButtons.java

@@ -57,6 +57,43 @@ public MarkdownActionButtons(@NonNull Context context, Document document) {
         super(context, document);
     }
 
+    @Override
+    public void onWebViewJavascriptCallback(final String[] args) {
+        if (isMarkdownCheckboxAction(args)) {
+            runViewModeCheckboxAction(args);
+            return;
+        }
+        super.onWebViewJavascriptCallback(args);
+    }
+
+    private boolean isMarkdownCheckboxAction(final String[] args) {
+        return args.length == 3 &&
+                "markdown-checkbox".equals(args[0]) &&
+                ("true".equals(args[2]) || "false".equals(args[2])) &&
+                _hlEditor != null;
+    }
+
+    private void runViewModeCheckboxAction(final String[] args) {
+        final int sourceIndex = GsTextUtils.tryParseInt(args[1], -1);
+        final Editable text = _hlEditor.getText();
+        if (sourceIndex <= 0 ||
+                sourceIndex >= text.length() - 1 ||
+                text.charAt(sourceIndex - 1) != '[' ||
+                text.charAt(sourceIndex + 1) != ']') {
+            return;
+        }
+
+        final char current = text.charAt(sourceIndex);
+        if (current != ' ' && current != 'x' && current != 'X') {
+            return;
+        }
+
+        final char replacement = "true".equals(args[2]) ? 'x' : ' ';
+        if (current != replacement) {
+            _hlEditor.withAutoFormatDisabled(() -> text.replace(sourceIndex, sourceIndex + 1, String.valueOf(replacement)));
+        }
+    }
+
     @Override
     protected @StringRes
     int getFormatActionsKey() {

app/src/main/java/net/gsantner/markor/format/markdown/MarkdownTextConverter.java

@@ -18,6 +18,7 @@
 import com.vladsch.flexmark.ext.footnotes.FootnoteExtension;
 import com.vladsch.flexmark.ext.gfm.strikethrough.StrikethroughSubscriptExtension;
 import com.vladsch.flexmark.ext.gfm.tasklist.TaskListExtension;
+import com.vladsch.flexmark.ext.gfm.tasklist.TaskListItem;
 import com.vladsch.flexmark.ext.gitlab.GitLabExtension;
 import com.vladsch.flexmark.ext.ins.InsExtension;
 import com.vladsch.flexmark.ext.jekyll.front.matter.JekyllFrontMatterExtension;
@@ -153,8 +154,6 @@ public class MarkdownTextConverter extends TextConverterBase {
     //########################
     // private static final String toDashChars = " -_"; // See HtmlRenderer.HEADER_ID_GENERATOR_TO_DASH_CHARS.getFrom(document)
     private static final Pattern linkPattern = Pattern.compile("\\[(.*?)\\]\\((.*?)(\\s+\".*\")?\\)");
-
-
     //########################
     //## Methods
     //########################
@@ -165,6 +164,9 @@ public String convertMarkup(String markup, Context context, boolean lightMode, b
         final MutableDataSet options = new MutableDataSet();
 
         options.set(Parser.EXTENSIONS, flexmarkExtensions);
+        final String sourceMarkup = markup;
+        final Document sourceDocument = flexmarkParser.parse(sourceMarkup);
+        final List<Integer> checkboxSourceIndices = getCheckboxSourceIndices(sourceDocument);
 
         options.set(Parser.SPACE_IN_LINK_URLS, true); // Allow links like [this](some filename with spaces.md)
 
@@ -179,6 +181,13 @@ public String convertMarkup(String markup, Context context, boolean lightMode, b
         final String checkedCheckbox = "<input type=checkbox class=task-list-item-checkbox checked=checked style='accent-color: #F04B4B;' />";
         options.set(TaskListExtension.ITEM_NOT_DONE_MARKER, checkedCheckbox.replace("checked=checked", ""))
                 .set(TaskListExtension.ITEM_DONE_MARKER, checkedCheckbox);
+        if (!checkboxSourceIndices.isEmpty()) {
+            onLoadJs += "var checkboxSourceIndices=" + checkboxSourceIndices + ";"
+                    + "var boxes=document.querySelectorAll('input.task-list-item-checkbox');"
+                    + "for(var i=0;i<boxes.length&&i<checkboxSourceIndices.length;i++){"
+                    + "boxes[i].markorSourceIndex=checkboxSourceIndices[i];"
+                    + "boxes[i].addEventListener('change',function(){Android.webViewJavascriptCallback(['markdown-checkbox',String(this.markorSourceIndex),this.checked?'true':'false']);});}";
+        }
 
         // GFM table parsing
         options.set(TablesExtension.WITH_CAPTION, false)
@@ -318,7 +327,7 @@ public String convertMarkup(String markup, Context context, boolean lightMode, b
 
         ////////////
         // Markup parsing - afterwards = HTML
-        Document document = flexmarkParser.parse(markup);
+        Document document = sourceMarkup.equals(markup) ? sourceDocument : flexmarkParser.parse(markup);
         converted = fmaText + flexmarkRenderer.withOptions(options).render(document);
 
         // After render changes: Fixes for Footnotes (converter creates footnote + <br> + ref#(click) --> remove line break)
@@ -375,6 +384,21 @@ private String escapeSpacesInLink(final String markup) {
         return sb.toString();
     }
 
+    private static List<Integer> getCheckboxSourceIndices(final Document document) {
+        final List<Integer> indices = new ArrayList<>();
+        collectCheckboxSourceIndices(document, indices);
+        return indices;
+    }
+
+    private static void collectCheckboxSourceIndices(final Node parent, final List<Integer> indices) {
+        for (Node node = parent.getFirstChild(); node != null; node = node.getNext()) {
+            if (node instanceof TaskListItem) {
+                indices.add(((TaskListItem) node).getMarkerSuffix().getStartOffset() + 1);
+            }
+            collectCheckboxSourceIndices(node, indices);
+        }
+    }
+
     private String getViewHlPrismIncludes(final String theme) {
 
         return CSS_PREFIX + "prism/themes/prism" + theme + ".min.css" + CSS_POSTFIX +
@@ -490,4 +514,4 @@ public static HtmlRenderer.HtmlRendererExtension create() {
             return new LineNumberIdExtension();
         }
     }
-}
+}