Picker: actually center lightweight popup buttons (#4819)

CodenameOne/src/com/codename1/ui/spinner/Picker.java

@@ -45,6 +45,7 @@
 import com.codename1.ui.events.ActionListener;
 import com.codename1.ui.layouts.BorderLayout;
 import com.codename1.ui.layouts.BoxLayout;
+import com.codename1.ui.layouts.FlowLayout;
 import com.codename1.ui.layouts.GridLayout;
 import com.codename1.ui.list.DefaultListModel;
 import com.codename1.ui.plaf.Border;
@@ -781,7 +782,11 @@ public void actionPerformed(ActionEvent evt) {
             switch (entry.alignment) {
                 case Component.CENTER:
                     if (center == null) {
-                        center = new Container(BoxLayout.x());
+                        // FlowLayout(CENTER) so the buttons actually center inside
+                        // the BorderLayout.CENTER slot below; BoxLayout.x() would
+                        // pack them at the slot's left edge, which is the bug from
+                        // https://github.com/codenameone/CodenameOne/issues/4819.
+                        center = new Container(new FlowLayout(Component.CENTER, Component.CENTER));
                         $(center).selectAllStyles().setMargin(0).setPadding(0).setBorder(Border.createEmpty()).setBgTransparency(0);
                     }
                     center.add(button);

scripts/hellocodenameone/common/src/main/java/com/codenameone/examples/hellocodenameone/tests/LightweightPickerButtonsScreenshotTest.java

@@ -1,54 +1,166 @@
 package com.codenameone.examples.hellocodenameone.tests;
 
+import com.codename1.ui.Component;
 import com.codename1.ui.Display;
 import com.codename1.ui.Form;
 import com.codename1.ui.layouts.BoxLayout;
 import com.codename1.ui.spinner.Picker;
+import com.codename1.ui.spinner.Picker.LightweightPopupButtonPlacement;
 import com.codename1.ui.util.UITimer;
 
 import java.time.LocalDate;
 import java.time.ZoneId;
 import java.util.Date;
 
+/**
+ * Captures the lightweight Picker popup with custom buttons across the
+ * placement and alignment combinations that matter. Originally a single
+ * baseline shot ({@code LightweightPickerButtons}); extended after
+ * issue #4819 where {@code Component.CENTER} alignment silently
+ * left-aligned the buttons.
+ *
+ * The variant count is intentionally trimmed to four: each variant
+ * cycle (popup show, throttled chunk emission, popup dismiss) costs
+ * roughly 5-6s on Android, and {@code Cn1ssDeviceRunner}'s per-test
+ * deadline is 30s on native platforms. The {@code _between_mixed}
+ * shot subsumes isolated LEFT / CENTER / RIGHT BETWEEN_CANCEL_AND_DONE
+ * captures: it lays out all three alignments in the same row with
+ * explicit L / C / R labels, so a regression that re-broke any of
+ * them would visibly collapse one column toward another.
+ */
 public class LightweightPickerButtonsScreenshotTest extends BaseTest {
+    private Form form;
     private Picker picker;
     private Date fixedDate;
     private Date fixedDatePlus7;
+    private Variant[] variants;
 
     @Override
     public boolean runTest() {
-        Form form = createForm("Picker Quick Buttons", BoxLayout.y(), "LightweightPickerButtons");
         fixedDate = toDate(LocalDate.of(2026, 4, 11));
         fixedDatePlus7 = toDate(LocalDate.of(2026, 4, 18));
+        variants = buildVariants();
+
+        form = new Form("Picker Quick Buttons", BoxLayout.y()) {
+            @Override
+            protected void onShowCompleted() {
+                runVariantsFrom(0);
+            }
+        };
         picker = new Picker();
         picker.setType(Display.PICKER_TYPE_DATE);
         picker.setUseLightweightPopup(true);
         picker.setDate(fixedDate);
+        form.add(picker);
+        form.show();
+        return true;
+    }
+
+    private Variant[] buildVariants() {
+        // Order matters for telemetry but not for correctness. The
+        // first entry's image name is "LightweightPickerButtons" to
+        // preserve the pre-existing golden (Today / +7 Days, both LEFT
+        // aligned) checked in under scripts/<port>/screenshots/.
+        return new Variant[] {
+                new Variant("LightweightPickerButtons", new Runnable() {
+                    @Override
+                    public void run() {
+                        addToday(LightweightPopupButtonPlacement.BETWEEN_CANCEL_AND_DONE, Component.LEFT);
+                        addPlus7(LightweightPopupButtonPlacement.BELOW_SPINNER, Component.LEFT);
+                    }
+                }),
+                new Variant("LightweightPickerButtons_between_mixed", new Runnable() {
+                    @Override
+                    public void run() {
+                        // Same placement, three alignments: covers the bug
+                        // from #4819 (CENTER had been left-aligning) and
+                        // the LEFT / RIGHT siblings in one shot.
+                        picker.addLightweightPopupButton("L", null,
+                                LightweightPopupButtonPlacement.BETWEEN_CANCEL_AND_DONE, Component.LEFT);
+                        picker.addLightweightPopupButton("C", null,
+                                LightweightPopupButtonPlacement.BETWEEN_CANCEL_AND_DONE, Component.CENTER);
+                        picker.addLightweightPopupButton("R", null,
+                                LightweightPopupButtonPlacement.BETWEEN_CANCEL_AND_DONE, Component.RIGHT);
+                    }
+                }),
+                new Variant("LightweightPickerButtons_above_center", new Runnable() {
+                    @Override
+                    public void run() {
+                        addToday(LightweightPopupButtonPlacement.ABOVE_SPINNER, Component.CENTER);
+                    }
+                }),
+                new Variant("LightweightPickerButtons_below_right", new Runnable() {
+                    @Override
+                    public void run() {
+                        addPlus7(LightweightPopupButtonPlacement.BELOW_SPINNER, Component.RIGHT);
+                    }
+                }),
+        };
+    }
+
+    private void addToday(int placement, int alignment) {
         picker.addLightweightPopupButton("Today", new Runnable() {
             @Override
             public void run() {
                 picker.setDate(fixedDate);
             }
-        });
+        }, placement, alignment);
+    }
+
+    private void addPlus7(int placement, int alignment) {
         picker.addLightweightPopupButton("+7 Days", new Runnable() {
             @Override
             public void run() {
                 picker.setDate(fixedDatePlus7);
             }
-        }, Picker.LightweightPopupButtonPlacement.BELOW_SPINNER);
-        form.add(picker);
-        form.show();
-        return true;
+        }, placement, alignment);
     }
 
-    @Override
-    protected void registerReadyCallback(Form parent, Runnable run) {
+    private void runVariantsFrom(final int index) {
+        if (index >= variants.length) {
+            done();
+            return;
+        }
+        final Variant variant = variants[index];
+        picker.clearLightweightPopupButtons();
         picker.setDate(fixedDate);
+        variant.configure.run();
         picker.startEditingAsync();
-        UITimer.timer(1000, false, parent, run);
+        // Wait for the popup to slide up before screenshotting. Each
+        // variant cycle (wait + chunk-throttled emit + popup dismiss)
+        // costs ~5s on Android, and the per-test deadline in
+        // Cn1ssDeviceRunner is 30s, so this budget can't be padded.
+        // 600ms is generous: the InteractionDialog transition is
+        // <300ms and setDate is applied synchronously above.
+        UITimer.timer(600, false, form, new Runnable() {
+            @Override
+            public void run() {
+                Cn1ssDeviceRunnerHelper.emitCurrentFormScreenshot(variant.imageName, new Runnable() {
+                    @Override
+                    public void run() {
+                        picker.stopEditing(new Runnable() {
+                            @Override
+                            public void run() {
+                                runVariantsFrom(index + 1);
+                            }
+                        });
+                    }
+                });
+            }
+        });
     }
 
     private static Date toDate(LocalDate date) {
         return new Date(date.atStartOfDay(ZoneId.systemDefault()).toInstant().toEpochMilli());
     }
+
+    private static final class Variant {
+        final String imageName;
+        final Runnable configure;
+
+        Variant(String imageName, Runnable configure) {
+            this.imageName = imageName;
+            this.configure = configure;
+        }
+    }
 }