具体来说,我们使用了CREATE TABLE IF NOT EXISTS语句来创建一个users表,该表有两个字段:id和name,其中id是主键,name是文本类型。然后,我们使用INSERT INTO语句向users表中插入一条记录,该记录的name字段为"Alice"``onCreate是在第一次打开数据库时调用的回调函数,用于创建数据库表和初始化数据。在Dart的sqflite库...
This tutorial shows you how to check whether a file, directory, or filesystem exists in Dart. If you create an application using Dart, there are several ways to check whether a file, directory, or filesystem link exists or not. Below are the examples which also work in any Dart frame...
输入flutter create -h可以查看所有的参数、选项。 $ flutter create -h Create a new Flutter project. If run on a project that already exists, this will repair the project, recreating any files that are missing. Global options: -h, --help Print this usage information. -v, --verbose Noisy l...
具体来说,我们使用了CREATE TABLE IF NOT EXISTS语句来创建一个users表,该表有两个字段:id和name,其中id是主键,name是文本类型。然后,我们使用INSERT INTO语句向users表中插入一条记录,该记录的name字段为"Alice"``onCreate是在第一次打开数据库时调用的回调函数,用于创建数据库表和初始化数据。在Dart的sqflite库...
if (pluginsFile.exists()) { pluginsFile.withReader('UTF-8') { reader -> plugins.load(reader) } } plugins.each { name, path -> def pluginDirectory = flutterProjectRoot.resolve(path).resolve('android').toFile() include ":$name" ...
{vardir =awaitgetApplicationDocumentsDirectory();///根据目录路径实例化 Directory 对象finalmyDir = Directory('${dir.path}/a/b/c');///判断目录是否存在varmyDirExists =awaitmyDir.exists();if(!myDirExists) {///创建目录///recursive 为 true 则会递归创建多级目录awaitmyDir.create(recursive:true)...
String path = join(documentsDirectory.path, "test.db"); var theDb = await openDatabase(path, version: 1, onCreate: _onCreate); return theDb; } 3. 创建数据库表 接下来,让我们看下如何使用SQFLite在flutter中创建一张数据库表 var db = await openDatabase(path); ...
I tried to add web support to an existing mobile app. The name of the app in the pubspec.yaml is a valid package name. However, the directory that contains the package (which is derived from a git repository name) contains a dash "-" in ...
(path,version:1,onCreate:(Database db,int version)async{awaitdb.execute('CREATE TABLE IF NOT EXISTS items(id INTEGER PRIMARY KEY, name TEXT)');});}_insertData()async{await_database.transaction((txn)async{int id=awaittxn.rawInsert('INSERT INTO items(name) VALUES("Item 1")');print('...
print(url);var _localPath = (await Path_provider.findLocalPath(context)) + '/Download/';final savedDir=Directory(_localPath);//判断下载路径是否存在bool hasExisted =await savedDir.exists();//不存在就新建路径if(!hasExisted) { savedDir.create(); ...