From ddfcd14252da644affc28e787c467971882c4e5e Mon Sep 17 00:00:00 2001
From: cnliucheng <brokenway@163.com>
Date: Wed, 8 Jul 2026 14:09:35 +0800
Subject: [PATCH] =?UTF-8?q?fix:=20timer=20=E5=90=8E=E5=8F=B0=E5=9B=9E?=
 =?UTF-8?q?=E5=88=B0=E5=89=8D=E5=8F=B0=E6=97=B6=E7=AB=8B=E5=8D=B3=E5=88=B7?=
 =?UTF-8?q?=E6=96=B0=20UI?=
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WeChat 在后台冻结 setInterval,用户从训练页切走再回来时
看到的还是离开前的画面。注册 wx.onAppShow 监听器,回到
前台立即强制 _tick() 一次,UI 跳到真实 elapsed,半程/30s/10s
等延迟到达的提醒也能补触发。
---
 utils/timer.js | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/utils/timer.js b/utils/timer.js
index c0d1c41..312d2c6 100644
--- a/utils/timer.js
+++ b/utils/timer.js
@@ -12,6 +12,17 @@ class Timer {
     this._running = false
     this._paused = false
     this._completed = false
+    this._appShowBound = false
+
+    // WeChat freezes setInterval while the mini-program is in background.
+    // When the user returns, force an immediate tick so the UI jumps to
+    // the actual elapsed time (instead of staying on the last pre-background
+    // frame) and any missed halfway / 30s / 10s reminders can still fire.
+    this._onAppShow = () => {
+      if (this._running && !this._paused) {
+        this._tick()
+      }
+    }
   }
 
   start(duration) {
@@ -24,6 +35,15 @@ class Timer {
     this._startTime = Date.now()
     this._tick()
     this._intervalId = setInterval(() => { this._tick() }, 1000)
+
+    // Register foreground listener (idempotent — we keep a flag so we don't
+    // double-register if start() is called multiple times in one session)
+    if (!this._appShowBound && typeof wx.onAppShow === 'function') {
+      try {
+        wx.onAppShow(this._onAppShow)
+        this._appShowBound = true
+      } catch (e) {}
+    }
   }
 
   pause() {