Android geofences that never fired: a permission promise that lied, and a cache that outlived the OS
A reminder tied to a place is the one feature where you cannot poll.
重點摘要
A permission promise resolved before the user answered, so the JS flow skipped the background-location step.
A cached “already armed” set in AsyncStorage survived reboot and app updates, preventing re-registration.
Boot, package-replaced, and periodic WorkManager jobs re-arm geofences; a larger radius fixed imprecise “home” locations.
This article traces three separate reasons Android geofences appeared to “never fire.” First, the permission bridge resolved too early: it told JavaScript the request had been denied before the user answered the system dialog, so the background-location step was never requested. Second, the app cached the last requested geofence set in AsyncStorage and incorrectly treated that cache as the source of truth, skipping native re-registration even after reboot or app updates had cleared Play services’ region state. The fix was to always re-arm unless both current and next sets are empty. Third, some “home” reminders missed because the geocoded anchor was too precise; a minimum radius for colloquial places addressed that. The post closes by noting that the repair logic is idempotent and cheap, so it should not be optimized away.
从未触发的 Android 地理围栏：一个撒谎的权限承诺，以及一个比操作系统更长寿的缓存
绑定地点的提醒，是唯一不能靠轮询解决的功能。
重點摘要
权限流程在用户尚未响应前就返回，导致 JS 跳过了后台定位步骤。
AsyncStorage 中的缓存被误当成真实状态，重启或更新后反而阻止重新注册。
开机、包更新和定期任务会重置围栏；“home”等口语地点则需要更大的半径。
这篇文章解释了 Android 地理围栏迟迟不触发的三个原因。首先是原生权限桥接过早返回：系统对话框还在等待用户选择时，JS 就收到了“denied”，于是后台定位权限的后续步骤根本没有执行。其次，应用把最后一次下发的围栏集合缓存到 AsyncStorage，却把这个缓存误当成真实状态；在重启或应用更新后，Play services 里的围栏已被清空，程序却因为缓存未变而跳过重新注册。修复方法是只有在新旧集合都为空时才跳过原生调用。最后，像“home”这样的口语地点因地理编码不够精确，需要提高最小半径。
Android 地理圍欄從未觸發：一個說謊的權限承諾，以及比作業系統更長命的快取
綁定地點的提醒，是唯一不能靠輪詢解決的功能。
重點摘要
權限流程在使用者尚未回覆前就回傳結果，導致 JS 跳過背景定位步驟。
AsyncStorage 的快取被誤當成真實狀態，重開機或更新後反而阻止重新註冊。
開機、套件更新與週期性工作會重設圍欄；「home」等口語地點則需要更大的半徑。
這篇文章說明 Android 地理圍欄遲遲不觸發的三個原因。首先是原生權限橋接太早回應，系統對話框還在等待使用者選擇時，JS 就已收到「denied」，因此背景定位權限的後續步驟根本沒走到。其次，App 把最後一次送出的圍欄清單存進 AsyncStorage，卻把這個快取誤認為真實狀態；在重開機或 App 更新後，Play services 內的圍欄已被清空，程式卻因快取相同而跳過重新註冊。修正方式是只在新舊集合都為空時才略過原生呼叫。最後，像「home」這類口語地點因地理編碼落點不準，需要加大最小半徑。