我在 GetX 中制作了兩個非常簡單的頁面來學習它。我為它創建了三個變數，一個是計數器，另一個是目的地和出發城市。計數器變數正在完美更新，而其他變數沒有改變它們的值。只有當我熱加載時它們才會改變。
如果您認為我遺漏了某些內容，或者這種疑問很常見，并且您看到了與我非常相似的示例，請分享它的鏈接或更正代碼（如果可以）。
這是我的課：
import 'package:get/get.dart';
class Controller extends GetxController {
var count = 0.obs;
var des = "Delhi".obs;
var dep = "Agra".obs;
void increment() {
count.value ;
update();
}
void updateDes(String input) {
des = input.obs;
}
void updateDep(String input) {
dep = input.obs;
}
}
這是第一頁（您可以查看第 14、30-52 行）-
import 'package:flutter/material.dart';
import 'package:flutter_application_firebase_noti_basics/my_controller.dart';
import 'package:flutter_application_firebase_noti_basics/new_home.dart';
import 'package:get/get.dart';
class Sample extends StatefulWidget {
const Sample({Key? key}) : super(key: key);
@override
_SampleState createState() => _SampleState();
}
class _SampleState extends State<Sample> {
final my_controller = Get.put(Controller());
@override
Widget build(BuildContext context) {
return Scaffold(
body: Padding(
padding: EdgeInsets.all(20.0),
child: Center(
child: Container(
width: 300,
height: 300,
color: Colors.grey[400],
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: [
Obx(
() => InkWell(
child: Text("${my_controller.des}"),
onTap: () {
Get.to(NewHome(
num: 1,
));
},
),
),
const SizedBox(
height: 20,
),
Obx(
() => InkWell(
child: Text('${my_controller.dep}'),
onTap: () {
Get.to(NewHome(
num: 2,
));
},
),
),
],
),
),
),
),
);
}
}
這是城市選擇頁面（您可能需要查看線路：32、93-103、121-125）-
import 'package:flutter/material.dart';
import 'package:get/get.dart';
import 'my_controller.dart';
class NewHome extends StatefulWidget {
int? num = 0;
NewHome({
Key? key,
this.num,
}) : super(key: key);
@override
_NewHomeState createState() => _NewHomeState();
}
class _NewHomeState extends State<NewHome> {
final List<Map<String, dynamic>> _allCities = [
{"id": 1, "city": "Delhi", "state": ""},
{"id": 2, "city": "Agra", "state": "UP"},
{"id": 3, "city": "Mumbai", "state": "Maharashtra"},
{"id": 4, "city": "Jaipur", "state": "Rajasthan"},
{"id": 5, "city": "Jodhpur", "state": "Rajasthan"},
{"id": 6, "city": "Ranchi", "state": "Jharkhand"},
{"id": 7, "city": "Dhanbad", "state": "Jharkhand"},
{"id": 8, "city": "Kanpur", "state": "UP"},
{"id": 9, "city": "Chandigarh", "state": "Punjab"},
{"id": 10, "city": "Meerut", "state": "UP"},
];
final controller = Get.put(Controller());
@override
Widget build(BuildContext context) {
return SafeArea(
child: Scaffold(
backgroundColor: const Color(0xffEEEDEF),
body: Column(
children: [
Padding(
padding: const EdgeInsets.symmetric(vertical: 10.0),
child: Row(
children: [
IconButton(
icon: const Icon(Icons.arrow_back),
color: Colors.orange,
onPressed: () {
Navigator.pop(context);
},
),
Container(
width: MediaQuery.of(context).size.width * 0.85,
height: 50.0,
decoration: BoxDecoration(
color: Colors.white,
borderRadius:
const BorderRadius.all(Radius.circular(5.0)),
border: Border.all(color: Colors.blueAccent)),
child: TextField(
decoration: InputDecoration(
hintText: "Enter Origin",
border: InputBorder.none,
contentPadding: const EdgeInsets.only(left: 10.0),
hintStyle: TextStyle(
fontSize: 15.0,
color: Colors.grey[500],
),
),
),
),
],
),
),
Align(
alignment: Alignment.centerLeft,
child: Padding(
padding: EdgeInsets.only(
left: MediaQuery.of(context).size.width * 0.04, top: 3.0),
child: Text(
'Popular Searches:',
style: TextStyle(
color: Colors.grey[500],
fontSize: MediaQuery.of(context).size.width * 0.035),
),
),
),
Expanded(
child: ListView.builder(
itemCount: _allCities.length,
itemBuilder: (context, index) {
return InkWell(
onTap: () {
controller.increment();
if (widget.num == 1) {
controller.updateDes(_allCities[index]['city']);
Get.back();
} else if (widget.num == 2) {
controller.updateDep(_allCities[index]['city']);
Get.back();
} else {
Get.back();
}
},
child: Padding(
padding: const EdgeInsets.only(
left: 18.0, top: 10.0, bottom: 15.0),
child: Text(
_allCities[index]['city'],
style: const TextStyle(
color: Colors.black,
fontSize: 15.0,
fontWeight: FontWeight.normal,
),
),
),
);
},
),
),
Obx(
() => Text("${controller.count} cities are selected",
style: const TextStyle(fontSize: 20.0)),
)
],
),
),
);
}
}
uj5u.com熱心網友回復：
那是因為您沒有正確更新值。使用反應式 (obs) 變數時，您需要更新變數的 value 屬性。
此外，您不應將 update 與 obs 變數一起使用，因為它們會自動更新。所以你的控制器將是：
class Controller extends GetxController {
var count = 0.obs;
var des = "Delhi".obs;
var dep = "Agra".obs;
void increment() {
count.value ;
// removed update()
}
void updateDes(String input) {
// changing from des = input.obs
des.value = input;
}
void updateDep(String input) {
// changing from dep = input.obs
dep.value = input;
}
}
uj5u.com熱心網友回復：
您需要從您的代碼中洗掉 update 和 .obs 從字串值中洗掉，如下所示：
import 'package:get/get.dart';
class Controller extends GetxController {
var count = 0.obs;
var des = "Delhi".obs;
var dep = "Agra".obs;
void increment() {
count.value ;
// remove this ---> update();
}
void updateDes(String input) {
des=input
// remove this---> des = input.obs;
}
void updateDep(String input) {
// remove this---> dep = input.obs;
dep=input
}
}
轉載請註明出處，本文鏈接：https://www.uj5u.com/ruanti/351464.html
上一篇：制作可重用的顫動小部件
下一篇：如何使背景影像在顫動中固定