Flutter 填坑录 （不定时更新）

一，内存爆表 > 图片缓存

/// State基类
class BaseState<T extends StatefulWidget> extends State<T>withAutomaticKeepAliveClientMixin,WidgetHelper,DialogHelper,EventListener {@mustCallSupervoid initState() {if (isListenEvent()) {EventManager.instance.listen(this);}//指定图片缓存大小，默认是1000PaintingBinding.instance.imageCache.maximumSize = 10;super.initState();LogEvent.onPageStart('${this}');}@mustCallSupervoid dispose() {super.dispose();deactivate();// 清理缓存PaintingBinding.instance.imageCache.clear();LogEvent.onPageEnd('${this}');if (isListenEvent()) {EventManager.instance.cancel(this);}}

二，iOS 字体缩小/消失/挤出屏幕等问题

import 'dart:math' as math;import 'package:flutter/material.dart';class NoScaleTextWidget extends StatelessWidget {final Widget child;const NoScaleTextWidget({Key key,@required this.child,}) : super(key: key);@overrideWidget build(BuildContext context) {return MaxScaleTextWidget(max: 1.0,child: child,);}
}class MaxScaleTextWidget extends StatelessWidget {final double max;final Widget child;const MaxScaleTextWidget({Key key,this.max = 1.2,@required this.child,}) : super(key: key);@overrideWidget build(BuildContext context) {var data = MediaQuery.of(context);var scale = math.min(max, data.textScaleFactor);return MediaQuery(data: data.copyWith(textScaleFactor: scale),child: child,);}
}class ScaleTextWidget extends StatelessWidget {final double scale;final Widget child;const ScaleTextWidget({Key key,@required this.scale,@required this.child,}) : super(key: key);@overrideWidget build(BuildContext context) {var data = MediaQuery.of(context);var scale = this.scale ?? data.textScaleFactor;return MediaQuery(data: data.copyWith(textScaleFactor: scale),child: child,);}
}

@overrideWidget build(BuildContext context) {loadData();return MaterialApp(builder: (ctx, w) {return MaxScaleTextWidget(max: 1.0,child: w,);},theme: ThemeData(primarySwatch: Colors.blue,textTheme: TextTheme(title: TextStyles.titleStyle, button: TextStyles.titleStyle),),home: homePage,

三，未授权导致图片保存失败

//每次都提示图片已保存成功，相册里并没有图片void _onSaveImage() async {print("_onImageSaveButtonPressed");final QrPainter painter = QrPainter(data: _appDownloadLink,color: const Color(0xff222222),emptyColor: const Color(0xffffffff),version: 4,gapless: true,);final ByteData imageData = await painter.toImageData(300.0);final result = await ImageGallerySaver.save(imageData.buffer.asUint8List());if (result) {toast("二维码已成功保存到手机相册");} else {toast("二维码保存到手机相册失败, 请查看App权限");}}

  @overridevoid initState() {super.initState();
// 先要授权访问相册PermissionHandler().requestPermissions(<PermissionGroup>[PermissionGroup.storage, // 在这里添加需要的权限]);}