初始化

lib/tools_base/toast.dart

@@ -0,0 +1,62 @@
+import 'package:oktoast/oktoast.dart' as ok;
+
+import 'debug_log.dart';
+
+/// Toast 位置
+enum ToastGravity { top, center, bottom }
+
+const _duration = Duration(seconds: 2);
+
+/// Toast 队列：一条消失后回调里再弹下一条（时序由 oktoast 精确控制）
+final _queue = <_ToastItem>[];
+bool _isShowing = false;
+
+class _ToastItem {
+  final String message;
+  final ToastGravity gravity;
+  _ToastItem(this.message, this.gravity);
+}
+
+/// 显示 Toast 消息（连续调用会排队，一条消失后再弹下一条）
+void showToast(String message, {ToastGravity? gravity}) {
+  if (message.isEmpty) return;
+  // 相邻重复的直接忽略，避免同一句刷屏
+  if (_queue.isNotEmpty && _queue.last.message == message) return;
+  _queue.add(_ToastItem(message, gravity ?? ToastGravity.center));
+  _drain();
+}
+
+void _drain() {
+  if (_isShowing || _queue.isEmpty) return;
+  _isShowing = true;
+  final item = _queue.removeAt(0);
+
+  var done = false;
+  void next() {
+    if (done) return;
+    done = true;
+    _isShowing = false;
+    _drain();
+  }
+
+  try {
+    ok.showToast(
+      item.message,
+      duration: _duration,
+      position: switch (item.gravity) {
+        ToastGravity.top => ok.ToastPosition.top,
+        ToastGravity.bottom => ok.ToastPosition.bottom,
+        ToastGravity.center => ok.ToastPosition.center,
+      },
+      onDismiss: next,
+    );
+  } catch (e) {
+    // OKToast 未挂载(启动早期)时 oktoast 直接抛错，不兜住的话 _isShowing 永久为 true → 全 App toast 静默失效
+    debugLog("showToast()...error:$e");
+    _queue.clear();
+    _isShowing = false;
+    return;
+  }
+  // 兜底：toast 被提前 dismiss 或 overlay 已销毁时 oktoast 不回调 onDismiss，超时自愈
+  Future.delayed(_duration + const Duration(milliseconds: 500), next);
+}