移动应用程序的平衡架构延长了项目和开发人员的寿命。
历史
认识亚历克斯。他需要开发一个用于制作购物清单的应用程序。Alex是一位经验丰富的开发人员,首先对产品提出了要求:
- 可以将产品移植到其他平台(watchOS,macOS,tvOS)
- 全自动应用程序回归
- iOS 13+支持
Alex最近熟悉了pointfree.com项目,在该项目中,Brandon和Stephen共享了他们对现代应用程序体系结构的见解。这就是Alex发现有关Composable Architecutre的方式。
可组合架构
在查看了Composable Architecture文档之后,Alex确定他正在处理符合设计要求的单向体系结构。从小册子中得出:
- 将项目分为模块;
- 数据驱动的UI-界面配置由其状态决定;
- 所有模块逻辑都包含在单元测试中。
- 接口的快照测试;
- 支持iOS 13 +,macOS,tvOS和watchOS;
- SwiftUI和UIKit支持。
在深入研究建筑学之前,让我们看一下诸如智能雨伞之类的对象。
如何描述伞的布置系统?
伞系统包含四个组件:
. : .
. .
. .
. 10 .
composable architecture . .
? , .
UI — [];
Action — ;
State — [];
Environment — [ ];
Reducer — , [] ;
Effect — , action reducer.
( 1)
.
. , .
struct ShoppingListState {
var products: [Product] = []
}
enum ShoppingListAction {
case addProduct
}
reducer :
let shoppingListReducer = Reducer { state, action, env in
switch action {
case .addProduct:
state.products.insert(Product(), at: 0)
return .none
}
}
:
struct Product {
var id = UUID()
var name = ""
var isInBox = false
}
enum ProductAction {
case toggleStatus
case updateName(String)
}
let productReducer = Reducer { state, action, env in
switch action {
case .toggleStatus:
state.isInBox.toggle()
return .none
case .updateName(let newName):
state.name = newName
return .none
}
}
, reducer , , . reducer .
UI .
UI
iOS 13+ Composable Architecture SwiftUI, .
, Store:
typealias ShoppingListStore = Store<ShoppingListState, ShoppingListAction>
let store = ShoppingListStore(
initialState: ShoppingListState(products: []),
reducer: shoppingListReducer,
environment: ShoppingListEnviroment()
)
Store viewModel MVVM — .
let view = ShoppingListView(store: store)
struct ShoppingListView: View {
let store: ShoppingListStore
var body: some View {
Text("Hello, World!")
}
}
Composable Architecture SwiftUI. , store ObservedObject, WithViewStore:
var body: some View {
WithViewStore(store) { viewStore in
NavigationView {
Text("\(viewStore.products.count)")
.navigationTitle("Shopping list")
.navigationBarItems(
trailing: Button("Add item") {
viewStore.send(.addProduct)
}
)
}
.navigationViewStyle(StackNavigationViewStyle())
}
}
Add item, . send(Action) .
, , :
struct ProductView: View {
let store: ProductStore
var body: some View {
WithViewStore(store) { viewStore in
HStack {
Button(action: { viewStore.send(.toggleStatus) }) {
Image(
systemName: viewStore.isInBox
? "checkmark.square"
: "square"
)
}
.buttonStyle(PlainButtonStyle())
TextField(
"New item",
text: viewStore.binding(
get: \.name,
send: ProductAction.updateName
)
)
}
.foregroundColor(viewStore.isInBox ? .gray : nil)
}
}
}
. ? .
enum ShoppingListAction {
//
case productAction(Int, ProductAction)
case addProduct
}
//
// .. ,
let shoppingListReducer: Reducer<ShoppingListState, ShoppingListAction, ShoppingListEnviroment> = .combine(
// ,
productReducer.forEach(
// Key path
state: ShoppingListState.products,
// Case path
action: /ShoppingListAction.productAction,
environment: { _ in ProductEnviroment() }
),
Reducer { state, action, env in
switch action {
case .addProduct:
state.products.insert(Product(), at: 0)
return .none
// productReducer
case .productAction:
return .none
}
}
)
. .
UI :
var body: some View {
WithViewStore(store) { viewStore in
NavigationView {
List {
//
ForEachStore(
// store
store.scope(
state: \.products,
action: ShoppingListAction.productAction
),
//
content: ProductView.init
)
}
.navigationTitle("Shopping list")
.navigationBarItems(
trailing: Button("Add item") {
viewStore.send(.addProduct)
}
)
}
.navigationViewStyle(StackNavigationViewStyle())
}
}
150 , .
2 — (in progress)
第3部分-扩展功能,添加产品删除和分类(正在进行中)
第4部分-添加列表缓存并转到商店(正在进行中)
资料来源
产品清单第1部分:github.com
方法作者门户:pointfree.com
可组合架构的来源:https : //github.com/pointfreeco/swift-composable-architecture