库
导入核心库
import 'dart:io';
void main() {
var f = new File('README.md');
var content = f.readAsStringSync();
print(content);
}
导入第三方库
编写 pubspec.yaml
name: hxl
dependencies:
dio: 1.0.9
程序调用
import 'package:dio/dio.dart';
void main() async {
Dio dio = new Dio();
Response<String> response = await dio.get("https://www.baidu.com");
print(response.data);
}
导入文件
import './phone.dart';
void main() {
var xm = Phone('android');
xm.startup();
xm.shutdown();
}
前缀
import './phone.dart';
import './phone1.dart' as pp;
void main() {
var xm = Phone('android');
xm.startup();
xm.shutdown();
var xm1 = pp.Phone('android');
xm1.startup();
xm1.shutdown();
}
筛选包内容
// import './phone.dart' hide AndroidPhone;
import './phone.dart' show IOSPhone;
void main() {
var xm = IOSPhone();
xm.startup();
xm.shutdown();
}
hideo筛掉某几个包
show只使用某几个包
延迟载入
import './phone.dart' deferred as pp;
void main() async {
var run = true;
if (run) {
await pp.loadLibrary();
var xm = pp.Phone('android');
xm.startup();
xm.shutdown();
}
}
loadLibrary()方式在需要的时候载入包
可提高程序启动速度
用在不常使用的功能
用在载入时间过长的包
