Flutter 的一些小技巧

1. 获取状态栏高度

import 'dart:ui'; MediaQueryData.fromWindow(window).padding.top

2. 设置AppBar的高度

Scaffold( appBar: PreferredSize( child: AppBar( ), preferredSize: Size.fromHeight(screenSize.height * 0.07)) );

3. 系统默认的AppBar、TabBar高度

在Dart Packages/flutter/src/material/constans.dart

/// The height of the toolbar component of the [AppBar]. const double kToolbarHeight = 56.0; /// The height of the bottom navigation bar. const double kBottomNavigationBarHeight = 56.0; /// The height of a tab bar containing text. const double kTextTabBarHeight = 48.0; /// The amount of time theme change animations should last. const Duration kThemeChangeDuration = Duration(milliseconds: 200); /// The radius of a circular material ink response in logical pixels. const double kRadialReactionRadius = 20.0; /// The amount of time a circular material ink response should take to expand to its full size. const Duration kRadialReactionDuration = Duration(milliseconds: 100); /// The value of the alpha channel to use when drawing a circular material ink response. const int kRadialReactionAlpha = 0x1F; /// The duration of the horizontal scroll animation that occurs when a tab is tapped. const Duration kTabScrollDuration = Duration(milliseconds: 300); /// The horizontal padding included by [Tab]s. const EdgeInsets kTabLabelPadding = EdgeInsets.symmetric(horizontal: 16.0); /// The padding added around material list items. const EdgeInsets kMaterialListPadding = EdgeInsets.symmetric(vertical: 8.0);

4. 获取当前时间戳

var now = new DateTime.now(); print(now.millisecondsSinceEpoch); //单位毫秒，13位时间戳 /** 或者 */ /** 返回当前时间戳 */ static int currentTimeMillis() { return new DateTime.now().millisecondsSinceEpoch; }

5.时间戳转化成日期

var now = new DateTime.now(); var a=now.millisecondsSinceEpoch; //时间戳 print(DateTime.fromMillisecondsSinceEpoch(a));

6. 获取控件大小和相对屏幕位置

1.首先先需要对控件进行渲染 初始化GlobalKey ：GlobalKey anchorKey = GlobalKey(); 2.在需要测量的控件的下面添加key： child: Text("点击弹出悬浮窗", style: TextStyle(fontSize: 20), key: anchorKey ), 3.获取控件的坐标： RenderBox renderBox = anchorKey.currentContext.findRenderObject(); var offset = renderBox.localToGlobal(Offset.zero); 控件的横坐标：offset.dx 控件的纵坐标：offset.dy 如果想获得控件正下方的坐标： RenderBox renderBox = anchorKey.currentContext.findRenderObject(); var offset = renderBox.localToGlobal(Offset(0.0, renderBox.size.height)); 控件下方的横坐标：offset.dx 控件下方的纵坐标：offset.dy 4.获取控件的大小： RenderBox renderBox = anchorKey.currentContext.findRenderObject(); final size = renderBox.size;

 7.有网络请求的地方基本上就有md5

dart有内置的md5加密包，先引入头文件：

import 'dart:convert'; import 'package:convert/convert.dart'; import 'package:crypto/crypto.dart';

md5加密方法：

// md5 加密 String generateMd5(String data) { var content = new Utf8Encoder().convert(data); var digest = md5.convert(content); // 这里其实就是 digest.toString() return hex.encode(digest.bytes); }

8. flutter 引入图片资源

可以单个图片引入，也可以整个文件夹引入

转载于:https://www.cnblogs.com/joe235/p/11498060.html