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> with AutomaticKeepAliveClientMixin, WidgetHelper, DialogHelper, EventListener { @mustCallSuper void initState() { if (isListenEvent()) { EventManager.instance.listen(this); } //指定图片缓存大小，默认是1000 PaintingBinding.instance.imageCache.maximumSize = 10; super.initState(); LogEvent.onPageStart('${this}'); } @mustCallSuper void dispose() { super.dispose(); deactivate(); // 清理缓存 PaintingBinding.instance.imageCache.clear(); LogEvent.onPageEnd('${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); @override Widget 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); @override Widget 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); @override Widget build(BuildContext context) { var data = MediaQuery.of(context); var scale = this.scale ?? data.textScaleFactor; return MediaQuery( data: data.copyWith(textScaleFactor: scale), child: child, ); } }

@override Widget 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"); } }

@override void 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 ]); }