98 lines
3.2 KiB
Dart
98 lines
3.2 KiB
Dart
import 'package:flutter/material.dart';
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import 'package:flutter/services.dart';
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import 'package:flutter_riverpod/flutter_riverpod.dart';
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import 'package:shared_preferences/shared_preferences.dart';
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/// 显示方向偏好：跟随系统 / 竖屏 / 横屏。
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///
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/// 与主题、语言并列，作为「我的」页可手动切换的显示设置；切换后通过
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/// [SystemChrome.setPreferredOrientations] 实时生效，并重渲染界面（横屏沿用
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/// NavigationRail 布局，竖屏沿用 NavigationBar 布局，二者共用同一套橙白主题，
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/// 视觉风格保持一致）。
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enum DisplayOrientation {
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/// 跟随系统（默认）：允许全部四个方向，由设备物理朝向决定。
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system,
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/// 仅竖屏。
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portrait,
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/// 仅横屏。
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landscape,
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}
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const String _kDisplayOrientation = 'display_orientation';
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/// 将偏好映射为 [SystemChrome] 需要的设备方向列表。
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List<DeviceOrientation> deviceOrientationsFor(DisplayOrientation mode) {
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switch (mode) {
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case DisplayOrientation.portrait:
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return const [DeviceOrientation.portraitUp];
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case DisplayOrientation.landscape:
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return const [DeviceOrientation.landscapeLeft, DeviceOrientation.landscapeRight];
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case DisplayOrientation.system:
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return const [
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DeviceOrientation.portraitUp,
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DeviceOrientation.portraitDown,
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DeviceOrientation.landscapeLeft,
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DeviceOrientation.landscapeRight,
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];
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}
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}
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/// 立即应用显示方向（调用 [SystemChrome.setPreferredOrientations]）。
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void applyDisplayOrientation(DisplayOrientation mode) {
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SystemChrome.setPreferredOrientations(deviceOrientationsFor(mode));
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}
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/// 从持久化读取已保存偏好；异常或无记录时返回 [DisplayOrientation.system]。
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Future<DisplayOrientation> loadSavedOrientation() async {
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try {
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final prefs = await SharedPreferences.getInstance();
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final v = prefs.getString(_kDisplayOrientation);
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if (v != null) {
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for (final e in DisplayOrientation.values) {
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if (e.name == v) return e;
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}
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}
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} catch (_) {
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// 忽略：SharedPreferences 不可用时退化为系统。
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}
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return DisplayOrientation.system;
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}
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/// 显示方向偏好管理（持久化 + 实时生效）。
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class DisplayOrientationNotifier extends Notifier<DisplayOrientation> {
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@override
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DisplayOrientation build() {
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// 首选项在 main 启动期已应用；这里异步回读以保证 UI 选中态与持久值一致。
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_load();
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return DisplayOrientation.system;
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}
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Future<void> _load() async {
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final saved = await loadSavedOrientation();
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if (saved != state) {
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state = saved;
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applyDisplayOrientation(saved);
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}
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}
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/// 切换显示方向：更新状态、即时生效并持久化。
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Future<void> set(DisplayOrientation mode) async {
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state = mode;
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applyDisplayOrientation(mode);
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try {
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final prefs = await SharedPreferences.getInstance();
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await prefs.setString(_kDisplayOrientation, mode.name);
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} catch (_) {
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// 忽略持久化失败，运行时仍生效。
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}
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}
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}
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/// 显示方向偏好提供者。
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final displayOrientationProvider =
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NotifierProvider<DisplayOrientationNotifier, DisplayOrientation>(
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DisplayOrientationNotifier.new,
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);
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