Flutter异常上报及性能监控实现

        1. 页面异常监测

         在Flutter中，通常用FlutterError监测Flutter框架抛出的异常，用runZonedGuarded监测应用中用户代码异常。

            

class AppGuarded {run(Widget app) {//1. 用FlutterError监测flutter框架抛出的异常FlutterError.onError = (FlutterErrorDetails details) async {//线上环境，将异常交给zone统一处理if (kReleaseMode) {Zone.current.handleUncaughtError(details.exception, details.stack!);} else {//开发期间，走Console抛出FlutterError.dumpErrorToConsole(details);}};//2. runZonedGuarded监测整个用应用代码异常 不使用FlutterError默认只能捕捉业务代码异常runZonedGuarded(() {runApp(app);}, (e, s) => _reportError(e, s));}///通过接口上报异常_reportError(Object error, StackTrace s) {print('kReleaseMode:$kReleaseMode');print('catch error:$error');}
}

        2. 监测页面流畅性（帧率）

        帧率监测在Flutter中通常通过在SchedulerBinding中注册fps相关回调来实现。通常需要保留最近若干个FrameTiming的总耗时，计算其平均值，以消除不必要数据波动。

void start() {SchedulerBinding.instance.addTimingsCallback(_onReportTimings);
}
// 不需监听时移除
void stop() {SchedulerBinding.instance.removeTimingsCallback(_onReportTimings);
}
void _onReportTimings(List<FrameTiming> timings) {// TODO
}

         3. 页面显示耗时（FCP）

         记录页面初始化和首次上屏时间，然后计算其时间差即可。

@overrideinitState() {super.initState();//1. 记录页面创建时间double startTime = time(0);//2.注册首帧显示时间回调WidgetsBinding.instance.addPostFrameCallback((timeStamp) {double endTime = time(0);print('WidgetsBinding Test-${(context as Element).size}');});

        4. 页面PV监测

        页面PV监测核心是检测到页面栈的变化，以便统计出页面曝光次数。如果应用采用自定义导航框架，只需在导航框架正确位置添加埋点即可。若采用的是系统默认的导航框架，则可通过继承NavigatorObserver，捕获Navigator的didPush和didPop回调。

//导航栈的变化监听
class MyNavigator extends NavigatorObserver{@overridevoid didPop(Route<dynamic> route, Route<dynamic> previousRoute) {super.didPop(route, previousRoute);var previousName = '';if (previousRoute == null) {previousName = 'null';}else {previousName = previousRoute.settings.name;}print('YM----->NavObserverDidPop--Current:' + route.settings.name + '  Previous:' + previousName);}@overridevoid didPush(Route<dynamic> route, Route<dynamic> previousRoute) {super.didPush(route, previousRoute);var previousName = '';if (previousRoute == null) {previousName = 'null';}else {previousName = previousRoute.settings.name;}print('YM-------NavObserverDidPush-Current:' + route.settings.name + '  Previous:' + previousName);}