Fix #5345: multiline TextArea text/hint jumps vertically when editing starts

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

@@ -151,6 +151,9 @@ public class TextArea extends Component implements ActionSource, TextHolder {
     private final EventDispatcher listeners = new EventDispatcher();
     private ActionListener doneListener;
     private int valign = defaultValign;
+    /// True once setVerticalAlignment() has been called, so the multi-line TOP
+    /// default in getVerticalAlignment() no longer overrides an explicit choice.
+    private boolean verticalAlignmentSet;
     private int linesToScroll = 1;
     //private int modifierFlag = 0x00000;
     /// Unsupported characters is a string that contains characters that cause issues
@@ -1380,6 +1383,15 @@ void paintHint(Graphics g) {
         if (Display.getInstance().isNativeEditorVisible(this) && Display.impl.nativeEditorPaintsHint()) {
             return;
         }
+        // For multi-row text areas, keep the hint vertically aligned with where
+        // the text will actually be rendered/edited so it doesn't sit in the
+        // middle while the cursor is on the first line (issue #5345). Single-line
+        // fields and one-row growable fields (e.g. a chat input) keep their
+        // existing (centered) hint behavior since there is no meaningful gap.
+        Label hint = getHintLabelImpl();
+        if (hint != null && !isSingleLineTextArea() && getActualRows() > 1) {
+            hint.setVerticalAlignment(getVerticalAlignment());
+        }
         super.paintHint(g);
     }
 
@@ -1852,11 +1864,16 @@ boolean shouldShowHint() {
         return "".equals(getText());
     }
 
-    /// Returns the vertical alignment of the text field.
+    /// Returns the vertical alignment of the text field, one of: CENTER, TOP, BOTTOM
     ///
-    /// For multi-line text areas, this alignment is applied only while there is extra
-    /// vertical space in the component. If the text content uses all available height
-    /// (or overflows), the rendering naturally starts from the top.
+    /// Multi-line text areas default to #TOP, regardless of the theme default
+    /// (`textCmpVAlignInt`, which is meant for single-line fields). Single-line fields
+    /// keep the theme default. A value passed to #setVerticalAlignment(int) is always
+    /// honored as-is, so an explicit #CENTER / #BOTTOM still works (e.g. for display
+    /// text). For editable multi-line areas the #TOP default also keeps the lightweight
+    /// rendering aligned with the native editor, which top-aligns its content on every
+    /// current platform, so the text, cursor and hint don't jump when editing starts
+    /// and ends (issue #5345).
     ///
     /// #### Returns
     ///
@@ -1870,6 +1887,9 @@ boolean shouldShowHint() {
     ///
     /// - #BOTTOM
     public int getVerticalAlignment() {
+        if (!verticalAlignmentSet && !isSingleLineTextArea()) {
+            return TOP;
+        }
         return valign;
     }
 
@@ -1879,6 +1899,11 @@ public int getVerticalAlignment() {
     /// vertical space in the component. If there is no extra room, alignment becomes
     /// effectively top-aligned because content already fills the available area.
     ///
+    /// Setting a value here overrides the multi-line #TOP default described in
+    /// #getVerticalAlignment(): the value you pass is honored even for an editable
+    /// multi-line area (which may then visibly shift when its native editor, which
+    /// top-aligns, takes over).
+    ///
     /// #### Parameters
     ///
     /// - `valign`: alignment value
@@ -1895,6 +1920,7 @@ public void setVerticalAlignment(int valign) {
             throw new IllegalArgumentException("Alignment can't be set to " + valign);
         }
         this.valign = valign;
+        this.verticalAlignmentSet = true;
     }
 
     /// {@inheritDoc}

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

@@ -412,6 +412,63 @@ void testVerticalAlignmentRejectsInvalidValues() {
         assertThrows(IllegalArgumentException.class, () -> textArea.setVerticalAlignment(Component.BASELINE));
     }
 
+    @FormTest
+    void testMultilineDefaultsToTop() {
+        // Regression test for #5345: with a CENTER theme default a multi-line text
+        // area reports TOP by default (the theme default is meant for single-line
+        // fields). For an editable area this matches the top-aligning native editor,
+        // so the text doesn't jump when editing starts and ends.
+        int previous = TextArea.getDefaultValign();
+        TextArea.setDefaultValign(Component.CENTER);
+        try {
+            TextArea editable = new TextArea("text text", 3, 20);
+            editable.setEditable(true);
+            assertEquals(Component.TOP, editable.getVerticalAlignment());
+
+            TextArea nonEditable = new TextArea("text text", 3, 20);
+            nonEditable.setEditable(false);
+            assertEquals(Component.TOP, nonEditable.getVerticalAlignment());
+        } finally {
+            TextArea.setDefaultValign(previous);
+        }
+    }
+
+    @FormTest
+    void testExplicitVerticalAlignmentOverridesMultilineDefault() {
+        // An explicit setVerticalAlignment() is honored even for a multi-line area,
+        // so display text can still be centered/bottom-aligned.
+        int previous = TextArea.getDefaultValign();
+        TextArea.setDefaultValign(Component.CENTER);
+        try {
+            TextArea textArea = new TextArea("text text", 3, 20);
+            textArea.setEditable(false);
+
+            textArea.setVerticalAlignment(Component.CENTER);
+            assertEquals(Component.CENTER, textArea.getVerticalAlignment());
+
+            textArea.setVerticalAlignment(Component.BOTTOM);
+            assertEquals(Component.BOTTOM, textArea.getVerticalAlignment());
+        } finally {
+            TextArea.setDefaultValign(previous);
+        }
+    }
+
+    @FormTest
+    void testSingleLineKeepsThemeVerticalAlignment() {
+        // Single-line fields keep the theme default (they center vertically in their
+        // native editor).
+        int previous = TextArea.getDefaultValign();
+        TextArea.setDefaultValign(Component.CENTER);
+        try {
+            TextArea textArea = new TextArea("text", 1, 20);
+            textArea.setSingleLineTextArea(true);
+            textArea.setEditable(true);
+            assertEquals(Component.CENTER, textArea.getVerticalAlignment());
+        } finally {
+            TextArea.setDefaultValign(previous);
+        }
+    }
+
     @FormTest
     void testVerticalAlignmentScreenshotStates() {
         Form form = new Form("TextArea VAlign", BoxLayout.y());