Merge pull request #29 from iWECon/combine

Support Combine

Author: iwecon

Demo/Demo/Preview1ViewController.swift

@@ -7,6 +7,7 @@
 
 import UIKit
 import StackKit
+import Combine
 
 class Preview1ViewController: UIViewController {
 
@@ -15,6 +16,17 @@ class Preview1ViewController: UIViewController {
     let briefLabel = UILabel()
 
     let container = HStackView(alignment: .center)
+    
+    @Published var name = "iWECon/StackKit"
+    @Published var brief = "The best way to use HStack and VStack in UIKit, and also supports Spacer and Divider."
+    
+    var cancellables: Set<AnyCancellable> = []
+    
+    deinit {
+        // ⚠️ important
+        // cleanup at deinit
+        cancellables.forEach({ $0.cancel() })
+    }
 
     override func viewDidLoad() {
         super.viewDidLoad()
@@ -25,11 +37,11 @@ class Preview1ViewController: UIViewController {
         logoView.layer.cornerCurve = .continuous
         logoView.backgroundColor = .systemGroupedBackground
 
-        nameLabel.text = "iWECon/StackKit"
+        nameLabel.text = name
         nameLabel.font = .systemFont(ofSize: 14, weight: .medium)
         nameLabel.textColor = .black
 
-        briefLabel.text = "The best way to use HStack and VStack in UIKit, and also supports Spacer and Divider."
+        briefLabel.text = brief
         briefLabel.font = .systemFont(ofSize: 12, weight: .light)
         briefLabel.textColor = .black
         briefLabel.numberOfLines = 0
@@ -46,11 +58,23 @@ class Preview1ViewController: UIViewController {
             logoView.stack.size(80)
             VStackView(alignment: .left, distribution: .spacing(6)) {
                 nameLabel
-                briefLabel.stack.maxWidth(220)
+                    .stack
+                    .receive(text: $name, storeIn: &cancellables)
+                
+                briefLabel
+                    .stack.maxWidth(220)
+                    .receive(text: $brief, storeIn: &cancellables)
             }
         }
 
         self.view.addSubview(container)
+        
+        // update combine value and refresh layout container
+        DispatchQueue.main.asyncAfter(wallDeadline: .now() + 2) {
+            self.name = "Designed by iWECon"
+            self.brief = "Version: 1.2.3"
+            self.container.setNeedsLayout()
+        }
     }
 
     override func viewDidLayoutSubviews() {

README.md

@@ -2,6 +2,8 @@
 
 ☝️ A layout library similar to SwiftUI.
 
+🔥 Support `Combine` (available iOS 13.0+)
+
 ⚠️ If you have any questions or new ideas, you can bring me a PR at any time.
 
 
@@ -23,6 +25,8 @@ HStackView(alignment: .center, distribution: .spacing(14), padding: UIEdgeInsets
 ![Demo](Demo/preview2.png)
 
 
+⚠️ If you have any question, please see the demo in `Demo/Demo.xcodeproj` or submit issue.
+
 💡 There are no more examples, you can help to complete/optimize.
 
 
@@ -85,7 +89,6 @@ VStackView {
 }
 ```
 
-
 ### Change and update
 
 ```swift
@@ -96,6 +99,34 @@ briefLabel.text = "Bump version to 1.2.2"
 stackContainer.setNeedsLayout() // or .sizeToFit() 
 ```
 
+### Combine
+
+```swift
+
+import Combine
+
+// ...
+@Published var name: String = "StackKit"
+
+var cancellables = Set<AnyCancellable>()
+
+// ...
+HStackView {
+    UILabel()
+        .stack
+        .then {
+            $0.font = .systemFont(ofSize: 16)
+            $0.textColor = .systemPink
+        }
+        .receive(text: $name, storeIn: &cancellables)
+}
+
+// update name
+self.name = "StackKit version 1.2.3"
+// update stackView
+stackView.setNeedsLayout()
+```
+
 # 🤔 
 
 I'm not very good at writing documents. If you have the advantages in this regard, please submit PR to me. Thank you very much.

Sources/StackKit/UIView+StackKit/UIView+Combine.swift

@@ -0,0 +1,122 @@
+//
+//  File.swift
+//  
+//
+//  Created by bro on 2022/11/22.
+//
+
+import UIKit
+import Combine
+
+fileprivate func safetyAccessUI(_ closure: @escaping () -> Void) {
+    if Thread.isMainThread {
+        closure()
+    } else {
+        DispatchQueue.main.async {
+            closure()
+        }
+    }
+}
+
+@available(iOS 13.0, *)
+extension StackKitCompatible where Base: UIView {
+
+    @discardableResult
+    public func receive<Value>(
+        publisher: Published<Value>.Publisher,
+        storeIn cancellables: inout Set<AnyCancellable>,
+        sink receiveValue: @escaping ((Base, Published<Value>.Publisher.Output) -> Void)
+    ) -> Self
+    {
+        let v = self.view
+        publisher.sink { [weak v] output in
+            guard let v else { return }
+            receiveValue(v, output)
+        }.store(in: &cancellables)
+        return self
+    }
+
+    @discardableResult
+    public func receive(
+        isHidden publisher: Published<Bool>.Publisher,
+        storeIn cancellables: inout Set<AnyCancellable>
+    ) -> Self
+    {
+        receive(publisher: publisher, storeIn: &cancellables) { view, output in
+            safetyAccessUI {
+                view.isHidden = output
+            }
+        }
+        return self
+    }
+}
+
+/**
+ 这里由于设计逻辑，会有个问题
+ 
+ 系统提供的 receive(on: DispatchQueue.main) 虽然也可以
+    ⚠️ 但是：DispatchQueue 是个调度器
+ 任务添加后需要等到下一个 loop cycle 才会执行
+ 这样就会导致一个问题：
+    ❌ 在主线程中修改值，并触发 `container.setNeedsLayout()` 的时候，
+ `setNeedsLayout` 会先执行，而 `publisher` 会将任务派发到下一个 loop cycle (也就是 setNeedsLayout 和 receive 先后执行的问题)
+ 所以这里采用 `safetyAccessUI` 来处理线程问题
+ */
+
+@available(iOS 13.0, *)
+extension StackKitCompatible where Base: UILabel {
+    
+    @discardableResult
+    public func receive(
+        text publisher: Published<String>.Publisher,
+        storeIn cancellables: inout Set<AnyCancellable>
+    ) -> Self
+    {
+        receive(publisher: publisher, storeIn: &cancellables) { view, output in
+            safetyAccessUI {
+                view.text = output
+            }
+        }
+    }
+    
+    
+    @discardableResult
+    public func receive(
+        text publisher: Published<String?>.Publisher,
+        storeIn cancellables: inout Set<AnyCancellable>
+    ) -> Self
+    {
+        receive(publisher: publisher, storeIn: &cancellables) { view, output in
+            safetyAccessUI {
+                view.text = output
+            }
+        }
+    }
+    
+    @discardableResult
+    public func receive(
+        attributedText publisher: Published<NSAttributedString>.Publisher,
+        storeIn cancellables: inout Set<AnyCancellable>
+    ) -> Self
+    {
+        receive(publisher: publisher, storeIn: &cancellables) { view, output in
+            safetyAccessUI {
+                view.attributedText = output
+            }
+        }
+    }
+    
+    @discardableResult
+    public func receive(
+        attributedText publisher: Published<NSAttributedString?>.Publisher,
+        storeIn cancellables: inout Set<AnyCancellable>
+    ) -> Self
+    {
+        receive(publisher: publisher, storeIn: &cancellables) { view, output in
+            safetyAccessUI {
+                view.attributedText = output
+            }
+        }
+    }
+    
+}