Use fixed date in ValidatorLightweightPicker screenshot test to stabilize output (#4738)

* Use java.time for fixed picker screenshot date

* Harden screenshot date and iOS PNG chunking

* Fix picker date setup without forbidden Date constructor

* Harden screenshot chunking and fix picker button dates

* Fix iOS screenshot chunk format regression

* Revert screenshot helper regressions

* Updated Android screenshot

Signed-off-by: liannacasper <67953602+liannacasper@users.noreply.github.com>

---------

Signed-off-by: liannacasper <67953602+liannacasper@users.noreply.github.com>

Author: liannacasper

scripts/android/screenshots/ValidatorLightweightPicker.png

@@ -6,31 +6,34 @@
 import com.codename1.ui.spinner.Picker;
 import com.codename1.ui.util.UITimer;
 
-import java.util.Calendar;
+import java.time.LocalDate;
+import java.time.ZoneId;
 import java.util.Date;
 
 public class LightweightPickerButtonsScreenshotTest extends BaseTest {
     private Picker picker;
+    private Date fixedDate;
+    private Date fixedDatePlus7;
 
     @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));
         picker = new Picker();
         picker.setType(Display.PICKER_TYPE_DATE);
         picker.setUseLightweightPopup(true);
-        picker.setDate(new Date());
+        picker.setDate(fixedDate);
         picker.addLightweightPopupButton("Today", new Runnable() {
             @Override
             public void run() {
-                picker.setDate(new Date());
+                picker.setDate(fixedDate);
             }
         });
         picker.addLightweightPopupButton("+7 Days", new Runnable() {
             @Override
             public void run() {
-                Calendar cal = Calendar.getInstance();
-                cal.add(Calendar.DAY_OF_MONTH, 7);
-                picker.setDate(cal.getTime());
+                picker.setDate(fixedDatePlus7);
             }
         }, Picker.LightweightPopupButtonPlacement.BELOW_SPINNER);
         form.add(picker);
@@ -40,7 +43,12 @@ public void run() {
 
     @Override
     protected void registerReadyCallback(Form parent, Runnable run) {
+        picker.setDate(fixedDate);
         picker.startEditingAsync();
         UITimer.timer(1000, false, parent, run);
     }
+
+    private static Date toDate(LocalDate date) {
+        return new Date(date.atStartOfDay(ZoneId.systemDefault()).toInstant().toEpochMilli());
+    }
 }

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

@@ -9,6 +9,8 @@
 import com.codename1.ui.validation.LengthConstraint;
 import com.codename1.ui.validation.Validator;
 
+import java.time.LocalDate;
+import java.time.ZoneId;
 import java.util.ArrayList;
 import java.util.Date;
 import java.util.List;
@@ -17,14 +19,21 @@ public class ValidatorLightweightPickerScreenshotTest extends BaseTest {
     private Picker picker;
     private final List<TextField> fields = new ArrayList<>();
     private boolean originalValidateOnEveryKey;
+    private Date fixedBirthDate;
 
     @Override
     public boolean runTest() {
         Form form = createForm("Validator + Picker", BoxLayout.y(), "ValidatorLightweightPicker");
         originalValidateOnEveryKey = Validator.isValidateOnEveryKey();
         Validator.setValidateOnEveryKey(true);
 
-        PickerComponent birthDate = PickerComponent.createDate(new Date()).label("Birthdate");
+        fixedBirthDate = new Date(
+                LocalDate.of(2026, 4, 11)
+                        .atStartOfDay(ZoneId.systemDefault())
+                        .toInstant()
+                        .toEpochMilli()
+        );
+        PickerComponent birthDate = PickerComponent.createDate(fixedBirthDate).label("Birthdate");
         picker = birthDate.getPicker();
         picker.setUseLightweightPopup(true);
         form.add(birthDate);
@@ -50,6 +59,7 @@ protected void registerReadyCallback(Form parent, Runnable run) {
         for (TextField field : fields) {
             field.setText("x");
         }
+        picker.setDate(fixedBirthDate);
         picker.startEditingAsync();
         UITimer.timer(1000, false, parent, run);
     }