Initial commit

suixinkan/App/State/ToastCenter.swift

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+//
+//  ToastCenter.swift
+//  suixinkan
+//
+//  Created by Codex on 2026/6/18.
+//
+
+import Observation
+import SwiftUI
+
+@MainActor
+@Observable
+/// 全局 Toast 状态中心，负责保存和清除当前提示文案。
+final class ToastCenter {
+    fileprivate var message: String?
+
+    /// 显示一条全局 Toast 文案。
+    func show(_ message: String) {
+        self.message = message
+    }
+
+    /// 清除当前 Toast 文案。
+    func dismiss() {
+        message = nil
+    }
+}
+
+/// 全局 Toast 叠加层修饰器，负责把 Toast 展示到页面顶部。
+private struct GlobalToastOverlay: ViewModifier {
+    @Environment(ToastCenter.self) private var toastCenter
+
+    func body(content: Content) -> some View {
+        content
+            .overlay(alignment: .top) {
+                if let message = toastCenter.message {
+                    HStack(spacing: 10) {
+                        Image(systemName: "exclamationmark.triangle.fill")
+                            .font(.system(size: 14, weight: .semibold))
+
+                        Text(message)
+                            .font(.system(size: 13, weight: .medium))
+                            .lineLimit(2)
+
+                        Spacer(minLength: 0)
+
+                        Button("关闭") {
+                            toastCenter.dismiss()
+                        }
+                        .font(.system(size: 13, weight: .semibold))
+                    }
+                    .foregroundStyle(.white)
+                    .padding(.horizontal, 14)
+                    .padding(.vertical, 10)
+                    .background(Color.black.opacity(0.78), in: RoundedRectangle(cornerRadius: 12))
+                    .padding(.horizontal, 16)
+                    .padding(.top, 10)
+                    .transition(.move(edge: .top).combined(with: .opacity))
+                }
+            }
+            .animation(.easeInOut(duration: 0.18), value: toastCenter.message)
+    }
+}
+
+extension View {
+    /// 给任意根视图追加全局 Toast 展示能力。
+    func globalToastOverlay() -> some View {
+        modifier(GlobalToastOverlay())
+    }
+}