TextArea: revalidate parent when growByContent row count changes (#4741)

Author: liannacasper

CodenameOne/src/com/codename1/ui/TextArea.java

@@ -597,6 +597,13 @@ public void setText(String t) {
             //zero the ArrayList in order to initialize it on the next paint
             rowStrings = null;
         }
+        if (growByContent
+                && !Objects.equals(text, old)
+                && getParent() != null
+                && Display.getInstance().isTextEditing(this)
+                && textMightGrowByContent(old, text)) {
+            getParent().revalidateLater();
+        }
         if (!Objects.equals(text, old)) {
             fireDataChanged(DataChangedListener.CHANGED, -1);
         }
@@ -610,6 +617,53 @@ public void setText(String t) {
         repaint();
     }
 
+    private boolean textMightGrowByContent(String oldText, String newText) {
+        int oldNewLines = countNewLines(oldText);
+        int newNewLines = countNewLines(newText);
+        if (newNewLines > oldNewLines) {
+            return true;
+        }
+        if (newText == null || oldText == null || newText.length() <= oldText.length()) {
+            return false;
+        }
+        int cols = getColumns();
+        if (cols > 1) {
+            return estimateLineCount(newText, cols) > estimateLineCount(oldText, cols);
+        }
+        return false;
+    }
+
+    private int countNewLines(String value) {
+        if (value == null || value.length() == 0) {
+            return 0;
+        }
+        int count = 0;
+        for (int i = 0; i < value.length(); i++) {
+            if (value.charAt(i) == '\n') {
+                count++;
+            }
+        }
+        return count;
+    }
+
+    private int estimateLineCount(String value, int cols) {
+        if (value == null || value.length() == 0) {
+            return 1;
+        }
+        int lines = 0;
+        int segmentLength = 0;
+        for (int i = 0; i < value.length(); i++) {
+            if (value.charAt(i) == '\n') {
+                lines += Math.max(1, (segmentLength + cols - 1) / cols);
+                segmentLength = 0;
+            } else {
+                segmentLength++;
+            }
+        }
+        lines += Math.max(1, (segmentLength + cols - 1) / cols);
+        return lines;
+    }
+
     /// Convenience method for numeric text fields, returns the value as a number or invalid if the value in the
     /// text field isn't a number
     ///

maven/core-unittests/src/test/java/com/codename1/ui/TextAreaTest.java

@@ -137,6 +137,41 @@ void testGrowByContent() {
         assertFalse(textArea.isGrowByContent());
     }
 
+    @FormTest
+    void testGrowByContentRevalidatesParentWhenRowsGrowDuringEditing() {
+        TextArea textArea = new TextArea();
+        textArea.setRows(1);
+        textArea.setSingleLineTextArea(false);
+        textArea.setGrowByContent(true);
+        TrackingContainer parent = new TrackingContainer();
+        parent.add(textArea);
+        parent.revalidatedLater = false;
+        Display.impl.setFocusedEditingText(textArea);
+        try {
+            textArea.setText("Line 1");
+            parent.revalidatedLater = false;
+            textArea.setText("Line 1\nLine 2");
+            assertTrue(parent.revalidatedLater, "Parent should be revalidated when growByContent row count increases");
+        } finally {
+            Display.impl.setFocusedEditingText(null);
+        }
+    }
+
+    @FormTest
+    void testGrowByContentDoesNotRevalidateWhenNotEditing() {
+        TextArea textArea = new TextArea();
+        textArea.setRows(2);
+        textArea.setGrowByContent(true);
+        TrackingContainer parent = new TrackingContainer();
+        parent.add(textArea);
+        parent.revalidatedLater = false;
+
+        Display.impl.setFocusedEditingText(null);
+        textArea.setText("Line 1");
+
+        assertFalse(parent.revalidatedLater, "Parent should not be revalidated when text changes outside active editing");
+    }
+
     @FormTest
     void testEndsWith3Points() {
         TextArea textArea = new TextArea();
@@ -413,4 +448,17 @@ private TextArea createOverflowSample(int valign) {
         sample.setVerticalAlignment(valign);
         return sample;
     }
+
+    private static class TrackingContainer extends Container {
+        private boolean revalidatedLater;
+
+        TrackingContainer() {
+            super(BoxLayout.y());
+        }
+
+        @Override
+        public void revalidateLater() {
+            revalidatedLater = true;
+        }
+    }
 }