flutter知识
Posted BigSweetee
tags:
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flutter知识
几乎所有的ui和功能都是widget
flutter是单线程
程序入口为
void main() {
runApp(myApp1());
}
class MyApp3 extends StatelessWidget
需要添加padding可以使用Container
Widget titleSection = new Container(
padding: const EdgeInsets.all(32.0)
布局分为行和列
横向布局用Row
垂直布局用Column
new Row(
children: [
new Expanded(
child: new Column(
添加paddding
EdgeInsets.all(32.0),
EdgeInsets.only(bottom: 8.0),
添加text
new Text('41'),
添加icon
new Icon(
添加image网络图片和本地图片
new Image.network(
url或者本地图片路径,
height: 240.0,
fit: BoxFit.cover,
),
添加点击事件
new GestureDetector
页面跳转
Navigator.push(
context,
new MaterialPageRoute(builder: (context) => new MyApp3()),
);
context必须为StatefulWidget的context
添加一个listview
body: new ListView(
children: [
new Image.asset(
'images/lake.jpg',
height: 240.0,
fit: BoxFit.cover,
),
titleSection,
buttonSection,
textSection,
// ...
],
),
网络请求
导包
pubspec.yaml
http: '>=0.11.3+12'
import 'package:http/http.dart' as http;
import 'dart:convert';
loadData() async {
String dataURL = "https://jsonplaceholder.typicode.com/posts";
http.Response response = await http.get(dataURL);
print(json.decode(response.body));
}
数据库
SQLite for Flutter
和原生通信flutter调用android
获取手机电量
Future<void> _getBatteryLevel() async {
String batteryLevel;
try {
final int result = await methodChannel.invokeMethod('getBatteryLevel');
batteryLevel = 'Battery level: $result%.';
} on PlatformException {
batteryLevel = 'Failed to get battery level.';
}
print(batteryLevel);
// Fluttertoast.showToast(msg: batteryLevel);
}
android项目汇中
override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) {
MethodChannel(
flutterEngine.getDartExecutor(),
BATTERY_CHANNEL
).setMethodCallHandler { call, result ->
if (call.method.equals("getBatteryLevel")) {
val batteryLevel = getBatteryLevel()
if (batteryLevel != -1) {
result.success(batteryLevel)
} else {
result.error("UNAVAILABLE", "Battery level not available.", null)
}
} else {
result.notImplemented()
}
}
}
然后flutter中的result会收到回调
android 调用flutter
android
private fun native2Dart() {
val eventChannel = MethodChannel(flutterEngine?.dartExecutor, EVENT_CHANNEL)
eventChannel.invokeMethod("nihao", "android调用flutter", object : MethodChannel.Result {
override fun success(result: Any?) {
Log.e("plateform_channel", "success")
}
override fun error(errorCode: String?, errorMessage: String?, errorDetails: Any?) {
}
override fun notImplemented() {
}
})
}
dart
class homestate extends State<content> {
static const MethodChannel event =
MethodChannel('samples.flutter.io/receive');
@override
void initState() {
super.initState();
event.setMethodCallHandler((call) async {
print(call.arguments);
});
}
修改程序入口
flutter run -t lib/main2.dart //运行
flutter build apk -t lib/main2.dart //打包
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