1

flutter_app/android/app/src/main/AndroidManifest.xml

@@ -1,6 +1,8 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
     <uses-permission android:name="android.permission.CAMERA"/>
     <uses-permission android:name="android.permission.INTERNET"/>
+    <!-- App 内更新安装 APK（PackageInstaller 会话安装，见 InstallerChannel.kt） -->
+    <uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES"/>
     <application
         android:label="视野"
         android:name="${applicationName}"

flutter_app/android/app/src/main/kotlin/com/example/observer/InstallerChannel.kt

@@ -0,0 +1,139 @@
+package com.example.observer
+
+import android.app.PendingIntent
+import android.content.Intent
+import android.content.pm.PackageInstaller
+import android.net.Uri
+import android.os.Build
+import android.os.Handler
+import android.os.Looper
+import android.provider.Settings
+import java.io.File
+import io.flutter.embedding.android.FlutterActivity
+import io.flutter.embedding.engine.FlutterEngine
+import io.flutter.plugin.common.EventChannel
+import io.flutter.plugin.common.MethodCall
+import io.flutter.plugin.common.MethodChannel
+
+/**
+ * 原生 APK 安装通道（App 内更新安装）：PackageInstaller 会话安装，
+ * 安装进度经 EventChannel 实时回传 Flutter（下载进度由 Flutter 侧 http 流式下载自算）。
+ *
+ * 通道：
+ * - MethodChannel "observer/installer"：install(path)
+ *   - result.success("installing")：已提交安装
+ *   - result.success("permission_required")：未开「安装未知应用」，已拉起系统设置页
+ * - EventChannel "observer/installer/progress"：{event: progress/finished/failed, ...}
+ */
+class InstallerChannel(
+    private val activity: FlutterActivity,
+    private val engine: FlutterEngine,
+) {
+    private val messenger = engine.dartExecutor.binaryMessenger
+    private val method = MethodChannel(messenger, "observer/installer")
+    private val progress = EventChannel(messenger, "observer/installer/progress")
+
+    private var progressSink: EventChannel.EventSink? = null
+    private var activeSession: PackageInstaller.Session? = null
+
+    fun register() {
+        method.setMethodCallHandler { call: MethodCall, result: MethodChannel.Result ->
+            when (call.method) {
+                "install" -> install(call.argument<String>("path") ?: "", result)
+                else -> result.notImplemented()
+            }
+        }
+        progress.setStreamHandler(object : EventChannel.StreamHandler {
+            override fun onListen(arguments: Any?, events: EventChannel.EventSink) {
+                progressSink = events
+            }
+
+            override fun onCancel(arguments: Any?) {
+                progressSink = null
+            }
+        })
+    }
+
+    private fun install(path: String, result: MethodChannel.Result) {
+        val file = File(path)
+        if (!file.exists()) {
+            result.error("FILE_NOT_FOUND", "APK 文件不存在: $path", null)
+            return
+        }
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O &&
+            !activity.packageManager.canRequestPackageInstalls()
+        ) {
+            val intent = Intent(
+                Settings.ACTION_MANAGE_UNKNOWN_APP_SOURCES,
+                Uri.parse("package:${activity.packageName}"),
+            ).addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
+            activity.startActivity(intent)
+            result.success("permission_required")
+            return
+        }
+        try {
+            val pm = activity.packageManager
+            val params = PackageInstaller.SessionParams(PackageInstaller.SessionParams.MODE_FULL_INSTALL).apply {
+                setSize(file.length())
+            }
+            val sessionId = pm.packageInstaller.createSession(params)
+            val session = pm.packageInstaller.openSession(sessionId)
+            activeSession = session
+            // API 36 起 registerSessionCallback(int, ...) 变体被移除，只剩全局注册形式，
+            // 回调按 sessionId 过滤，避免响应其他会话事件
+            val callback = object : PackageInstaller.SessionCallback() {
+                override fun onCreated(id: Int) {}
+
+                override fun onBadgingChanged(id: Int) {}
+
+                override fun onActiveChanged(id: Int, active: Boolean) {}
+
+                override fun onProgressChanged(id: Int, progressPercent: Float) {
+                    if (id != sessionId) return
+                    emit("progress", "progress" to progressPercent.toInt())
+                }
+
+                override fun onFinished(id: Int, success: Boolean) {
+                    if (id != sessionId) return
+                    emit("finished", "success" to success)
+                    pm.packageInstaller.unregisterSessionCallback(this)
+                    activeSession = null
+                }
+            }
+            pm.packageInstaller.registerSessionCallback(callback, Handler(Looper.getMainLooper()))
+            // 写 APK 到会话：1MB 缓冲流式拷贝，完成后 commit 弹系统确认框
+            Thread {
+                try {
+                    session.openWrite("apk", 0, file.length()).use { out ->
+                        file.inputStream().use { input ->
+                            val buf = ByteArray(1 shl 20)
+                            while (true) {
+                                val n = input.read(buf)
+                                if (n < 0) break
+                                out.write(buf, 0, n)
+                            }
+                        }
+                    }
+                    val sender = PendingIntent.getActivity(
+                        activity,
+                        0,
+                        Intent(activity, MainActivity::class.java),
+                        PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE,
+                    ).intentSender
+                    session.commit(sender)
+                } catch (e: Exception) {
+                    session.abandon()
+                    emit("failed", "error" to (e.message ?: "安装会话写入失败"))
+                    activeSession = null
+                }
+            }.start()
+            result.success("installing")
+        } catch (e: Exception) {
+            result.error("INSTALL_FAILED", e.message, null)
+        }
+    }
+
+    private fun emit(event: String, vararg pairs: Pair<String, Any>) {
+        progressSink?.success(mapOf("event" to event, *pairs))
+    }
+}

flutter_app/android/app/src/main/kotlin/com/example/observer/MainActivity.kt

@@ -5,6 +5,7 @@ import io.flutter.embedding.engine.FlutterEngine
 
 class MainActivity : FlutterActivity() {
     private var cameraChannel: CameraChannel? = null
+    private var installerChannel: InstallerChannel? = null
 
     override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
         super.configureFlutterEngine(flutterEngine)
@@ -13,6 +14,8 @@ class MainActivity : FlutterActivity() {
         // configureFlutterEngine（onCreate 阶段）只注册通道与 viewFactory，
         // 实际 bindToLifecycle 由 Flutter 相机页 start 时触发（此时已 RESUMED）
         cameraChannel = CameraChannel(this, flutterEngine).also { it.register() }
+        // App 内更新安装 APK（PackageInstaller 会话安装 + 进度回传）
+        installerChannel = InstallerChannel(this, flutterEngine).also { it.register() }
     }
 
     override fun onDestroy() {

flutter_app/docs/PaymentApi.md

@@ -116,6 +116,6 @@
 ```
 
 - **仅 Android 调用**：`UpdateChecker.fetch()` 在非 Android 平台直接返回空（iOS 不做版本下发，用户从 App Store 自行更新）
-- 客户端以「语义化版本号」按数字段比较（`1.10.0 > 1.9.9`），**服务器版本 > 已装版本即强制更新**：弹全屏阻塞页（禁返回，仅「立即更新」），`url_launcher` 打开系统浏览器下载固定地址 `{apiBaseUrl}/download/observer-latest.apk`（后端静态托管，永远是最新 APK）
+- 客户端以「语义化版本号」按数字段比较（`1.10.0 > 1.9.9`），**服务器版本 > 已装版本即强制更新**：弹全屏阻塞页（禁返回，仅「立即更新」），**App 内直接下载安装**（不跳浏览器）：http 流式下载固定地址 `{apiBaseUrl}/download/observer-latest.apk`（后端静态托管，永远是最新 APK）到缓存目录（`.part` 原子落盘后改名，避免半包）→ 原生 `PackageInstaller` 会话安装（`InstallerChannel.kt`），页面实时显示**下载进度与安装进度**；首次安装需在系统设置允许「安装未知应用」（未开启时自动拉起系统设置页，APK 已缓存、返回后再次点击直达安装）
 - **双版本比较防反复提示**：用户点「立即更新」时把服务器版本号写入本地（`SessionStore.accepted_update_version`）；判定条件是服务器版本 > 已装版本 **或** 服务器版本 > 已接受版本。APK 版本号不递增（每次打的包 versionName 相同）时，已更新完成的手机重启也不会再次弹更新
 - 网络异常/响应异常时静默跳过检查，不阻塞启动

flutter_app/lib/update/installer.dart

@@ -0,0 +1,49 @@
+import 'package:flutter/services.dart';
+
+/// 安装进度事件（原生 PackageInstaller 会话回调经 EventChannel 回传）
+class InstallEvent {
+  /// progress / finished / failed
+  final String event;
+
+  /// event=progress 时的安装进度 0-100
+  final int progress;
+
+  /// event=finished 时是否安装成功
+  final bool? success;
+
+  /// event=failed 时的错误描述
+  final String? error;
+
+  const InstallEvent({
+    required this.event,
+    this.progress = 0,
+    this.success,
+    this.error,
+  });
+}
+
+/// App 内安装 APK：原生侧 PackageInstaller 会话安装（InstallerChannel.kt）
+class ApkInstaller {
+  static const _method = MethodChannel('observer/installer');
+  static const _progress = EventChannel('observer/installer/progress');
+
+  /// 提交安装。返回 installing（已进入安装流程）/ permission_required
+  /// （未允许「安装未知应用」，原生侧已拉起系统设置页）。
+  static Future<String> install(String path) =>
+      _method.invokeMethod<String>('install', {'path': path}).then(
+            (v) => v ?? 'installing',
+          );
+
+  /// 安装进度流：progress(0-100) → finished(success) / failed(error)
+  static Stream<InstallEvent> progress() {
+    return _progress.receiveBroadcastStream().map((e) {
+      final m = e as Map;
+      return InstallEvent(
+        event: m['event'] as String? ?? '',
+        progress: (m['progress'] as num?)?.toInt() ?? 0,
+        success: m['success'] as bool?,
+        error: m['error'] as String?,
+      );
+    });
+  }
+}

flutter_app/lib/update/update_screen.dart

@@ -1,12 +1,19 @@
+import 'dart:async';
+import 'dart:io';
+
 import 'package:flutter/material.dart';
+import 'package:http/http.dart' as http;
 import 'package:url_launcher/url_launcher.dart';
 
+import 'installer.dart';
+
 /// 强制更新页：检测到新版本时的全屏阻塞页。
-/// PopScope 禁返回（Android 系统返回 / iOS 边缘滑动均不可退出），
-/// 仅「立即更新」跳转系统浏览器下载 APK。
+/// PopScope 禁返回（Android 系统返回 / iOS 边缘滑动均不可退出）。
+/// 点「立即更新」在 App 内流式下载 APK（显示下载进度）→ PackageInstaller
+/// 会话安装（显示安装进度），不再跳浏览器。
 /// 点击更新时回调 onUpdateAccepted（调用方持久化服务器版本号，
 /// 使 APK 版本号不递增时也不反复提示）。
-class UpdateScreen extends StatelessWidget {
+class UpdateScreen extends StatefulWidget {
   final String version;
   final String url;
   final String notes;
@@ -20,20 +27,150 @@ class UpdateScreen extends StatelessWidget {
     this.onUpdateAccepted,
   });
 
+  @override
+  State<UpdateScreen> createState() => _UpdateScreenState();
+}
+
+enum _Stage { idle, downloading, installing, finished, failed }
+
+class _UpdateScreenState extends State<UpdateScreen> {
+  final http.Client _client = http.Client();
+  final File _apkFile = File('${Directory.systemTemp.path}/observer-latest.apk');
+  final File _apkPart =
+      File('${Directory.systemTemp.path}/observer-latest.apk.part');
+
+  _Stage _stage = _Stage.idle;
+
+  /// 进度百分比 0-100；null = 总量未知（不确定进度条）
+  double? _progress;
+  String? _message;
+  StreamSubscription<InstallEvent>? _installSub;
+
+  @override
+  void dispose() {
+    _installSub?.cancel();
+    _client.close();
+    super.dispose();
+  }
+
   Future<void> _launch() async {
-    onUpdateAccepted?.call();
-    final uri = Uri.tryParse(url);
-    if (uri == null) return;
+    if (_stage == _Stage.downloading ||
+        _stage == _Stage.installing ||
+        _stage == _Stage.finished) {
+      return;
+    }
+    setState(() {
+      _stage = _Stage.idle;
+      _message = null;
+    });
+    widget.onUpdateAccepted?.call();
+    if (!Platform.isAndroid) {
+      // 更新检查本就仅 Android 触发，这里兜底非 Android 走浏览器
+      final uri = Uri.tryParse(widget.url);
+      if (uri == null) return;
+      try {
+        await launchUrl(uri, mode: LaunchMode.externalApplication);
+      } catch (_) {}
+      return;
+    }
+    // APK 已下载完成（下载是原子落盘，.part 改名后文件才存在）→ 跳过下载直接安装
+    if (_apkFile.existsSync()) {
+      await _install();
+      return;
+    }
+    await _download();
+  }
+
+  Future<void> _download() async {
+    setState(() {
+      _stage = _Stage.downloading;
+      _progress = 0;
+    });
     try {
-      await launchUrl(uri, mode: LaunchMode.externalApplication);
+      if (_apkPart.existsSync()) _apkPart.deleteSync();
+      final res = await _client.send(http.Request('GET', Uri.parse(widget.url)));
+      if (res.statusCode != 200) {
+        throw HttpException('HTTP ${res.statusCode}');
+      }
+      final total = res.contentLength ?? -1;
+      final sink = _apkPart.openWrite();
+      var received = 0;
+      await for (final chunk in res.stream) {
+        sink.add(chunk);
+        received += chunk.length;
+        if (mounted && total > 0) {
+          setState(() => _progress = received / total * 100);
+        }
+      }
+      await sink.close();
+      // 原子落盘：下载完成后才重命名为正式文件，避免残留半包被当成完整 APK
+      _apkPart.renameSync(_apkFile.path);
+      if (!mounted) return;
+      await _install();
     } catch (_) {
-      // 跳转失败保持页面，用户可重试
+      if (_apkPart.existsSync()) _apkPart.deleteSync();
+      if (!mounted) return;
+      setState(() {
+        _stage = _Stage.failed;
+        _progress = null;
+        _message = '下载失败，请检查网络后重试';
+      });
+    }
+  }
+
+  Future<void> _install() async {
+    setState(() {
+      _stage = _Stage.installing;
+      _progress = 0;
+      _message = null;
+    });
+    await _installSub?.cancel();
+    _installSub = ApkInstaller.progress().listen((e) {
+      if (!mounted) return;
+      switch (e.event) {
+        case 'progress':
+          setState(() => _progress = e.progress.toDouble());
+          break;
+        case 'finished':
+          final ok = e.success == true;
+          setState(() {
+            _stage = ok ? _Stage.finished : _Stage.failed;
+            _message = ok ? '安装完成，请从桌面打开新版应用' : '安装失败，请重试';
+          });
+          break;
+        case 'failed':
+          setState(() {
+            _stage = _Stage.failed;
+            _message = e.error ?? '安装失败，请重试';
+          });
+          break;
+      }
+    }, onError: (Object _) {
+      if (!mounted) return;
+      setState(() {
+        _stage = _Stage.failed;
+        _message = '安装失败，请重试';
+      });
+    });
+    final result = await ApkInstaller.install(_apkFile.path);
+    if (!mounted) return;
+    if (result == 'permission_required') {
+      // 原生侧已拉起系统设置页；APK 已缓存，用户开启后返回再点直达安装
+      setState(() {
+        _stage = _Stage.failed;
+        _message = '请在系统设置中允许「安装未知应用」，返回后再次点击「立即更新」（APK 已缓存，无需重新下载）';
+      });
     }
   }
 
   @override
   Widget build(BuildContext context) {
     final theme = Theme.of(context);
+    final busy = _stage == _Stage.downloading || _stage == _Stage.installing;
+    final progressText = _stage == _Stage.downloading
+        ? (_progress == null ? '下载中…' : '下载中 ${_progress!.round()}%')
+        : (_progress == null ? '安装中…' : '安装中 ${_progress!.round()}%');
+
     return PopScope(
       canPop: false,
       child: Scaffold(
@@ -46,23 +183,47 @@ class UpdateScreen extends StatelessWidget {
                 Icon(Icons.system_update_alt,
                     size: 64, color: theme.colorScheme.primary),
                 const SizedBox(height: 16),
-                Text('发现新版本 $version',
+                Text('发现新版本 ${widget.version}',
                     style: theme.textTheme.headlineSmall),
                 const SizedBox(height: 12),
-                if (notes.isNotEmpty)
-                  Text(notes,
+                if (widget.notes.isNotEmpty)
+                  Text(widget.notes,
                       textAlign: TextAlign.center,
                       style: const TextStyle(height: 1.6)),
                 const SizedBox(height: 24),
+                if (busy) ...[
+                  LinearProgressIndicator(
+                    value: _progress == null ? null : _progress! / 100,
+                    minHeight: 6,
+                  ),
+                  const SizedBox(height: 12),
+                  Text(progressText),
+                  const SizedBox(height: 24),
+                ],
                 FilledButton.icon(
-                  onPressed: _launch,
+                  onPressed: busy || _stage == _Stage.finished
+                      ? null
+                      : _launch,
                   icon: const Icon(Icons.download),
-                  label: const Text('立即更新'),
+                  label: Text(_stage == _Stage.finished ? '已完成' : '立即更新'),
                   style: FilledButton.styleFrom(
                     minimumSize: const Size(200, 48),
                     textStyle: const TextStyle(fontSize: 16),
                   ),
                 ),
+                if (_message != null) ...[
+                  const SizedBox(height: 12),
+                  Text(
+                    _message!,
+                    textAlign: TextAlign.center,
+                    style: TextStyle(
+                      height: 1.5,
+                      color: _stage == _Stage.failed
+                          ? theme.colorScheme.error
+                          : Colors.green,
+                    ),
+                  ),
+                ],
                 const SizedBox(height: 12),
                 Text('不更新将无法继续使用',
                     style: theme.textTheme.bodySmall

flutter_app/pubspec.yaml

@@ -2,7 +2,7 @@ name: observer
 description: "视野 - 动物实时识别 (野鸡/生境), YOLOv8 + 充值付费"
 publish_to: 'none'
 
-version: 1.0.2+3
+version: 1.0.4+5
 
 environment:
   sdk: ^3.12.2