flutter · auto-submit · Sep 28, 2024 · Jul 1, 2024 · Jul 3, 2024 · Jul 3, 2024
diff --git a/packages/flutter/lib/src/cupertino/date_picker.dart b/packages/flutter/lib/src/cupertino/date_picker.dart
@@ -487,78 +487,74 @@ class CupertinoDatePicker extends StatefulWidget {
     bool showDayOfWeek, {
     bool standaloneMonth = false,
   }) {
-    String longestText = '';
+    final List<String> longTexts = <String>[];
 
     switch (columnType) {
       case _PickerColumnType.date:
-        // Measuring the length of all possible date is impossible, so here
-        // just some dates are measured.
         for (int i = 1; i <= 12; i++) {
-          // An arbitrary date.
-          final String date =
-              localizations.datePickerMediumDate(DateTime(2018, i, 25));
-          if (longestText.length < date.length) {
-            longestText = date;
-          }
+          final String date = localizations.datePickerMediumDate(DateTime(2018, i, 25));
+          longTexts.add(date);
         }
       case _PickerColumnType.hour:
         for (int i = 0; i < 24; i++) {
           final String hour = localizations.datePickerHour(i);
-          if (longestText.length < hour.length) {
-            longestText = hour;
-          }
+          longTexts.add(hour);
         }
       case _PickerColumnType.minute:
         for (int i = 0; i < 60; i++) {
           final String minute = localizations.datePickerMinute(i);
-          if (longestText.length < minute.length) {
-            longestText = minute;
-          }
+          longTexts.add(minute);
         }
       case _PickerColumnType.dayPeriod:
-        longestText =
-          localizations.anteMeridiemAbbreviation.length > localizations.postMeridiemAbbreviation.length
-            ? localizations.anteMeridiemAbbreviation
-            : localizations.postMeridiemAbbreviation;
+        longTexts.add(localizations.anteMeridiemAbbreviation);
+        longTexts.add(localizations.postMeridiemAbbreviation);
       case _PickerColumnType.dayOfMonth:
         int longestDayOfMonth = 1;
-        for (int i = 1; i <=31; i++) {
+        for (int i = 1; i <= 31; i++) {
           final String dayOfMonth = localizations.datePickerDayOfMonth(i);
-          if (longestText.length < dayOfMonth.length) {
-            longestText = dayOfMonth;
-            longestDayOfMonth = i;
-          }
+          longTexts.add(dayOfMonth);
+          longestDayOfMonth = i;
         }
         if (showDayOfWeek) {
           for (int wd = 1; wd < DateTime.daysPerWeek; wd++) {
             final String dayOfMonth = localizations.datePickerDayOfMonth(longestDayOfMonth, wd);
-            if (longestText.length < dayOfMonth.length) {
-              longestText = dayOfMonth;
-            }
+            longTexts.add(dayOfMonth);
           }
         }
       case _PickerColumnType.month:
         for (int i = 1; i <= 12; i++) {
           final String month = standaloneMonth
               ? localizations.datePickerStandaloneMonth(i)
               : localizations.datePickerMonth(i);
-          if (longestText.length < month.length) {
-            longestText = month;
-          }
+          longTexts.add(month);
         }
       case _PickerColumnType.year:
-        longestText = localizations.datePickerYear(2018);
+        longTexts.add(localizations.datePickerYear(2018));
     }
 
-    assert(longestText != '', 'column type is not appropriate');
+    assert(longTexts.isNotEmpty && longTexts.every((String text) => text.isNotEmpty), 'column type is not appropriate');
 
-    return TextPainter.computeMaxIntrinsicWidth(
-      text: TextSpan(
-        style: _themeTextStyle(context),
-        text: longestText,
-      ),
-      textDirection: Directionality.of(context),
-    );
+    return getColumnWidth(texts: longTexts, context: context);
+  }
+
+  /// Returns the width of column in the picker.
+  ///
+  /// This method is intended for testing only. It calculates the width of the
+  /// widest column in the picker based on the provided list of texts and the
+  /// given [BuildContext].
+  @visibleForTesting
+  static double getColumnWidth({
+    required List<String> texts,
+    required BuildContext context,
+    TextStyle? textStyle,
+  }) {
+    return texts.map((String text) => TextPainter.computeMaxIntrinsicWidth(
+        text: TextSpan(
+          style: textStyle ?? _themeTextStyle(context),
+          text: text,
+        ),
+        textDirection: Directionality.of(context),
+      )).reduce(math.max);
   }
 }
 

diff --git a/packages/flutter/test/cupertino/date_picker_test.dart b/packages/flutter/test/cupertino/date_picker_test.dart
@@ -8,6 +8,7 @@
 @Tags(<String>['reduced-test-set'])
 library;
 
+import 'dart:math' as math;
 import 'dart:ui';
 
 import 'package:flutter/cupertino.dart';
@@ -2414,6 +2415,50 @@ void main() {
 
     expect(find.byType(CupertinoPickerDefaultSelectionOverlay), findsExactly(4));
   });
+
+  testWidgets('CupertinoDatePicker accommodates widest text using table codepoints', (WidgetTester tester) async {
+    // |---------|
+    // |  0x2002 | // EN SPACE - 1/2 Advance
+    // |  0x2005 | // FOUR-PER-EM SPACE - 1/4 Advance
+    // |---------|
+    final List<String> testWords = <String>[
+      '\u2002' * 10, // Output: 10 * 1/2 = 5
+      '\u2005' * 20, // Output: 20 * 1/4 = 5
+    ];
+
+    await tester.pumpWidget(
+      CupertinoApp(
+        home: Center(
+          child: CupertinoDatePicker(
+            onDateTimeChanged: (DateTime date) {},
+            initialDateTime: DateTime(2018, 9, 15),
+          ),
+        ),
+      ),
+    );
+
+    final BuildContext context = tester.element(find.byType(CupertinoDatePicker));
+
+    const TextStyle textStyle = TextStyle(
+      fontSize: 21,
+      letterSpacing: 0.4,
+      fontWeight: FontWeight.normal,
+      color: CupertinoColors.label,
+    );
+
+    final List<double> widths = testWords.map((String word) => getColumnWidth(word, textStyle, context)).toList();
+
+    final double largestWidth = widths.reduce(math.max);
+
+    final double testWidth = CupertinoDatePicker.getColumnWidth(
+      texts: testWords,
+      context: context,
+      textStyle: textStyle,
+    );
+
+    expect(testWidth, equals(largestWidth));
+    expect(widths.indexOf(largestWidth), equals(1));
+  }, skip: isBrowser); // https://github.com/flutter/flutter/issues/39998
 }
 
 Widget _buildPicker({
@@ -2438,3 +2483,13 @@ Widget _buildPicker({
     ),
   );
 }
+
+double getColumnWidth(String text, TextStyle textStyle, BuildContext context) {
+  return TextPainter.computeMaxIntrinsicWidth(
+    text: TextSpan(
+      text: text,
+      style: textStyle,
+    ),
+    textDirection: Directionality.of(context),
+  );
+}