mvvm 0.1.3+4
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A Flutter MVVM. It uses property-based data binding to establish a connection between the ViewModel and the View, and drives the View changes through the ViewModel.

A Flutter MVVM (Model-View-ViewModel) implementation. It uses property-based data binding to establish a connection between the ViewModel and the View, and drives the View changes through the ViewModel.

一个 Flutter 的 MVVM(Model-View-ViewModel) 实现。 它使用基于属性 (property) 的数据绑定在视图模型 (ViewModel) 与视图 (View) 之间建立关联,并通过视图模型 (ViewModel) 驱动视图 (View) 变化。

#

Documentation & Full example

import 'package:flutter/widgets.dart';
import 'package:mvvm/mvvm.dart';
import 'dart:async';

// ViewModel
class Demo1ViewModel extends ViewModel {

  Demo1ViewModel() {
      // define bindable property
      propertyValue<String>(#time, initial: "");
      // timer
      start();
  }

  start() {
      Timer.periodic(const Duration(seconds: 1), (_) {
        var now = DateTime.now();
        // call setValue
        setValue<String>(#time, "${now.hour}:${now.minute}:${now.second}");
      });
  }
}

// View
class Demo1 extends View<Demo1ViewModel> {
  Demo1() : super(Demo1ViewModel());

  @override
  Widget buildCore(BuildContext context) {
    return Container(
        margin: EdgeInsets.symmetric(vertical: 100),
        padding: EdgeInsets.all(40),

        // binding
        child: $.watchFor(#time, 
            builder: $.builder1((t) => 
              Text(t, textDirection: TextDirection.ltr))));
  }
}

// run
void main() => runApp(Demo1());

mvvm

APIs #

ViewContext ($.*) #

Methods

watch<TValue>(ValueListenable<TValue> valueListenable, { ValueWidgetBuilder<TValue> builder, Widget child }) → Widget

绑定到指定 valueListenable, 当 valueListenable 值发生变化时, 使用 builder 构建 Widget

  • child 用于向构建方法中传入 Widget
// example
@override
Widget buildCore(BuildContext context) {
  return $.watch<String>($Model.prop1,
    builder: $.builder1((value) => Text(value)));
}

watchFor<TValue>(Object propertyKey, { ValueWidgetBuilder<TValue> builder, Widget child }) → Widget

绑定到指定属性, 当 propertyKey 对应属性值发生变化时, 使用 builder 构建 Widget

  • child 用于向构建方法中传入 Widget
// example
@override
Widget buildCore(BuildContext context) {
  return $.watchFor<String>(#account,
    builder: $.builder1((value) => Text(value)));
}

watchAny(Iterable<ValueListenable> valueListenable, { ValueWidgetBuilder<Iterable> builder, Widget child }) → Widget

绑定到指定 valueListenable 集合, 当任一 valueListenable 值发生变化时, 使用 builder 构建 Widget

  • builder 方法中 TValue 将被包装为 Iterable<dynamic>
  • child 用于向构建方法中传入 Widget
// example
@override
Widget buildCore(BuildContext context) {
  return $.watchAny([$Model.prop1, $Model.prop2],
    builder: $.builder1((values) => Text(values[0])));
}

watchAnyFor(Iterable<Object> prepertyKeys, { ValueWidgetBuilder<Iterable> builder, Widget child }) → Widget

绑定到指定属性集合, 当任一 propertyKeys 对应属性值发生变化时, 使用 builder 构建 Widget

  • builder 方法中 TValue 将被包装为 Iterable<dynamic>
  • child 用于向构建方法中传入 Widget
// example
@override
Widget buildCore(BuildContext context) {
  return $.watchAnyFor(const [#account, #password],
    builder: $.builder1((values) => Text(values[0])));
}

builder0(Widget builder()) → ValueWidgetBuilder

生成 Widget 构建方法

  • 通过 builder 指定一个无参的 Widget 构建方法
// example
@override
Widget buildCore(BuildContext context) {
  return $.watch<String>($Model.prop1,
    builder: $.builder0(() => Text("hello!")));
}

builder1<TValue>(Widget builder(TValue)) → ValueWidgetBuilder<TValue>

生成 Widget 构建方法

  • 通过 builder 指定一个接收 TValueWidget 构建方法
// example
@override
Widget buildCore(BuildContext context) {
  return $.watch<String>($Model.prop1,
    builder: $.builder1((value) => Text(value)));
}

builder2<TValue>(Widget builder(TValue, Widget)) → ValueWidgetBuilder<TValue>

生成 Widget 构建方法

  • 通过 builder 指定一个接收 TValue, WidgetWidget 构建方法
// example
@override
Widget buildCore(BuildContext context) {
  return $.watch<String>($Model.prop1,
    builder: $.builder2((value, child) => Column(children:[Text("$value"), child]),
    child: Text("child"));
}

$cond<TValue>(ValueListenable<TValue> valueListenable, { ValueWidgetBuilder<TValue> $true, ValueWidgetBuilder<TValue> $false, Widget child, bool valueHandle(TValue) }) → Widget

绑定到指定 valueListenable, 当 valueListenable 值发生变化时, 若值判定结果为 true 则使用 $true 构建 Widget, 否则使用 $false 构建 Widget

  • 当值类型不为 bool 时, 非 null 即被判定为 true, 否则判定为 false
  • 可通过指定 valueHandle 对值进行处理
  • child 用于向构建方法中传入 Widget
// example
@override
Widget buildCore(BuildContext context) {
  return $.$cond<int>($Model.prop1,
    $true: $.builder0(() => Text("tom!")),
    $false: $.builder0(() => Text("jerry!")),
    valueHandle: (value) => value == 1);
}

$condFor<TValue>(Object propertyKey, { ValueWidgetBuilder<TValue> $true, ValueWidgetBuilder<TValue> $false, Widget child, bool valueHandle(TValue) }) → Widget

绑定到指定属性, 当 propertyKey 对应属性值发生变化时, 若值判定结果为 true 则使用 $true 构建 Widget, 否则使用 $false 构建 Widget

  • 当值类型不为 bool 时, 非 null 即被判定为 true, 否则判定为 false
  • 可通过指定 valueHandle 对值进行处理
  • child 用于向构建方法中传入 Widget
// example
@override
Widget buildCore(BuildContext context) {
  return $.$condFor<String>(#account,
    $true: $.builder0(() => Text("tom!")),
    $false: $.builder0(() => Text("jerry!")),
    valueHandle: (value) => value == "tom");
}

 

$if<TValue>(ValueListenable<TValue> valueListenable, { ValueWidgetBuilder<TValue> builder, Widget child, bool valueHandle(TValue) }) → Widget

绑定到指定 valueListenable, 当值发生变化时, 若值判定结果为 true 时使用 builder 构建 Widget 否则不构建 Widget

  • 当值类型不为 bool 时, 非 null 即被判定为 true, 否则判定为 false
  • 可通过指定 valueHandle 对值进行处理
  • child 用于向构建方法中传入 Widget
// example
@override
Widget buildCore(BuildContext context) {
  return $.$if<int>($Model.prop1,
    builder: $.builder0(() => Text("tom!")),
    valueHandle: (value) => value == 1);
}

$ifFor<TValue>(Object propertyKey, { ValueWidgetBuilder<TValue> builder, Widget child, bool valueHandle(TValue) }) → Widget

绑定到指定属性, 当 propertyKey 对应属性值发生变化时, 若值判定结果为 true 时使用 builder 构建 Widget 否则不构建 Widget

  • 当值类型不为 bool 时, 非 null 即被判定为 true, 否则判定为 false
  • 可通过指定 valueHandle 对值进行处理
  • child 用于向构建方法中传入 Widget
// example
@override
Widget buildCore(BuildContext context) {
  return $.$ifFor<String>(#account,
    builder: $.builder0(() => Text("tom!")),
    valueHandle: (value) => value == "tom");
}

$switch<TKey, TValue>(ValueListenable<TValue> valueListenable, { Map<TKey, ValueWidgetBuilder<TValue>> options, ValueWidgetBuilder<TValue> defalut, Widget child, TKey valueToKey(TValue) }) → Widget

绑定到指定 valueListenable, 当 valueListenable 值发生变化时, 其值做为 keyoptions 中查找对应 Widget 构建方法, 若未找到则使用 default 构建, 如 defaultnull 则不构建 Widget

  • 如值与 optionskey 类型不同, 可通过指定 valueToKey 进行转换
  • child 用于向构建方法中传入 Widget
// example
@override
Widget buildCore(BuildContext context) {
  return $.$switch<String, int>($Model.prop1,
    options: { "1.": $.builder1((value) => Text("$value")),              
               "2.": $.builder0(() => Text("2")) },
    default: $.builder0(() => Text("default")),
    valueToKey: (value) => "${value}.");
}

$switchFor<TKey, TValue>(Object propertyKey, { Map<TKey, ValueWidgetBuilder<TValue>> options, ValueWidgetBuilder<TValue> defalut, Widget child, TKey valueToKey(TValue) }) → Widget

绑定到指定属性, 当 propertyKey 对应属性值发生变化时, 其值做为 keyoptions 中查找对应 Widget 构建方法, 若未找到则使用 default 构建, 如 defaultnull 则不构建 Widget

  • 如值与 optionskey 类型不同, 可通过指定 valueToKey 进行转换
  • child 用于向构建方法中传入 Widget
// example
@override
Widget buildCore(BuildContext context) {
  return $.$switchFor<String, int>(#account,
    options: { "tom": $.builder1((value) => Text("${value}! cat")),                    
               "jerry": $.builder0(() => Text("mouse")) },
    default: $.builder0(() => Text("default"));
}

ViewModel #

Methods

propertyValue<TValue>(Object propertyKey, { TValue initial }) → ViewModelProperty<TValue>

创建一个值属性

  • propertyKey 指定属性键
  • initial 指定初始值
// example
class PageViewModel extends ViewModel {
    PageViewModel() {
        propertyValue<String>(#name, initial: "tom");
    }
}

propertyAdaptive<TValue, TAdaptee extends Listenable>(Object propertyKey, TAdaptee adaptee, TValue getAdapteeValue(TAdaptee), void setAdapteeValue(TAdaptee, TValue), { TValue initial }) → AdaptiveViewModelProperty<TValue, TAdaptee>

创建一个适配属性

  • propertyKey 指定属性键
  • adaptee 被适配者实例,适配者必须继承自 Listenable
  • getAdapteeValue 指定从被适配者获取值的方法
  • setAdapteeValue 指定设置被适配者值的方法
  • initial 指定初始值
// example
class PageViewModel extends ViewModel {
    final TextEditingController _nameCtrl = TextEditingController();
    PageViewModel() {
        propertyAdaptive<String, TextEditingController>(
            #name, _nameCtrl,
            (v) => v.text,
            (a, v) => a.text = v,
            initial: name);
    }

    // TextField used
    TextEditingController get nameCtrl => _nameCtrl;
}

propertyAsync<TValue>(Object propertyKey, AsyncValueGetter<TValue> futureGetter, { TValue handle(TValue), TValue initial }) → AsyncViewModelProperty<TValue>

创建一个异步请求属性 要使用此属性的 ViewModel 需要 withAsyncViewModelMixin

  • propertyKey 指定属性键
  • futureGetter 用于获取 Future<TValue> 的方法
  • handle 指定请求成功时对结果进行处理的方法
  • onStart 指定请求发起时执行的方法
  • onEnd 指定请求结束时执行的方法
  • onSuccess 指定请求成功时执行的方法
  • onError 指定请求出错时执行的方法
  • initial 指定初始值
// example
class User {
  String name;
  User(this.name);
}

class RemoteService {
    Future<User> findUser() async {
        return Future.delayed(
        Duration(seconds: 3), () => User("tom_${DateTime.now().second}"));
    }
}

class PageViewModel extends ViewModel with AsyncViewModelMixin {
    final RemoteService _service;
    PageViewModel(this._service) {
        propertyAsync<User>(
            #findUserAsync,
            () => _service.findUser(),        
            handle: (User user) {
                user.name = "hello, ${user.name}";
                return user;
            });
    }

    // ViewModel used
    find() => invoke(#findUserAsync);
}

class PageView extends View<PageViewModel> {
    PageView(): super(PageViewModel(RemoteService()));

    @override
    Widget buildCore(BuildContext context) {
        return Column(children: [
            $.watchFor(#findUserAsync,
                builder: $.builder2((AsyncSnapshot<User> snapshot, child) =>
                            snapshot.connectionState == ConnectionState.waiting && snapshot.hasData 
                                ? Text("${snapshot.data.name}", textDirection: TextDirection.ltr)
                                : child),
                child: Text("empty", textDirection: TextDirection.ltr)), 
            RaisedButton(
                child: $.watchFor(#findUserAsync,
                    builder: $.builder2((AsyncSnapshot<User> snapshot, child) =>
                        snapshot.connectionState == ConnectionState.waiting
                            ? CircularProgressIndicator() : child),
                    child: Text("find", textDirection: TextDirection.ltr)), 
                // or: onPressed: () { $Model.find(); }
                onPressed: $Model.link(#findUserAsync))]);
    }
}

Documentation

License #

MIT

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A Flutter MVVM. It uses property-based data binding to establish a connection between the ViewModel and the View, and drives the View changes through the ViewModel.

Repository (GitHub)
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License

unknown (LICENSE)

Dependencies

flutter

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