在 iPhone 上使用应用程序时，iOS 会将该应用程序识别为“活动”。当您切换到另一个应用程序、按下主页(Home)按钮、滑动到主页或锁定您的 iPhone 时，iOS 会将应用程序暂停到后台。
尽管处于暂停状态，但某些应用程序仍然可以使用您的移动数据、Wi-Fi和位置/GPS 服务。但前提是你允许他们。在本文中，我们将解释什么是后台应用刷新(Background App Refresh)，以及如何使用该功能在后台使用设备资源管理应用。
什么是后台应用刷新？
以前，只有系统应用程序和服务可以在后台运行。2013 年 iOS 7 发生了变化——引入了后台应用刷新(App Refresh)。苹果(Apple)向第三方应用程序开发者开放了后台活动访问权限，并平等地将最终用户置于驾驶席上。
允许应用程序在后台运行有其好处：每次重新打开应用程序时，您都会获得最新的内容。但是存在电池耗尽(issue of battery drainage)和过度数据消耗的问题，特别是如果您使用具有数据上限/限制的互联网计划。
后台应用刷新(Background App Refresh)功能可帮助 iPhone 和 iPad 用户解决这些问题。如果您发现 iPhone 的电池消耗比平时更快，禁用后台刷新可能会有所帮助。
注意：(Note:) 后台(Background)刷新仅适用于在后台暂停的活动应用程序。已关闭的应用程序或您从应用程序启动器退出的应用程序(apps that you quit from the app launcher)不会刷新其内容，即使为应用程序启用了后台应用程序刷新也是如此。(Background App Refresh)您需要等待新打开的应用程序使用更新的信息刷新其内容。
如何启用和禁用后台应用刷新(Disable Background App Refresh)
(Background App Refresh)默认情况下，iPhone 和 iPad 上的后台应用程序刷新处于活动状态。这意味着暂停的应用程序将始终在后台检查新内容。您可以通过导航到设置(Settings)>常规( General )>后台应用刷新( Background App Refresh)来管理哪些应用使用此后台刷新功能。
Apple允许您根据设备使用的 Internet 连接类型自定义后台应用程序刷新的工作方式。(Background App Refresh)您可以将应用程序配置为始终后台刷新其内容（即使用Wi-Fi 和移动数据(Wi-Fi & Mobile Data)）或仅通过Wi-Fi连接。如果要禁用所有应用程序的后台刷新，请选择关闭。(Off)
您还可以关闭个别应用的后台刷新；只需在后台应用程序刷新(Background App Refresh)设置菜单中关闭应用程序旁边的开关即可。
为应用启用后台刷新的另一种方法是转到应用的设置菜单（设置(Settings )>应用名称( App Name)）并打开后台应用刷新(Background App Refresh)。
如果此选项显示为灰色，请返回后台应用刷新(Background App Refresh)菜单并确保为Wi-Fi 和移动数据(Wi-Fi & Mobile Data)启用后台刷新。如果后台应用刷新仍然显示为灰色，请继续下一部分以获取更多解决方案。
iPhone后台应用刷新灰显(Background App Refresh Greyed Out)？2修复方法(Ways)
如果您无法在 iPhone 或 iPad 上启用后台应用刷新(Background App Refresh)，我们已经为该问题编译了一些可能的解决方案。
1.禁用低功耗模式(1. Disable Low Power Mode)
低功耗模式(Low Power Mode)通过暂停消耗过多电池电量的应用程序和系统进程来帮助最大限度地延长 iPhone 的电池寿命。低功耗模式(Power Mode)会暂时禁用iCloud 照片(iCloud Photos)、后台应用刷新(Background App Refresh)、自动下载、动画壁纸等功能。
当您将手机充电至 80% 或更高时，iOS 会自动禁用低电量模式。(Low Power Mode)您还可以从控制中心(Control Center)或设置菜单手动禁用该功能。要关闭低功耗模式(Low Power Mode)，请打开控制中心(open the Control Center)并点击黄色电池图标(yellow battery icon)。
如果控制中心(Control Center)缺少电池图标，请转到设置(Settings )>电池( Battery)并关闭低功耗模式(Low Power Mode)。
2.禁用后台刷新的屏幕时间限制(2. Disable Screen Time Restriction for Background Refresh)
Screen Time有一个内容管理和隐私部分，可让您防止第三方对您的 iPhone 应用程序和设置进行未经授权的更改。如果您的 iPhone 有屏幕时间(Time)限制，请确保您没有阻止后台应用刷新(Background App Refresh)。以下是如何检查。
1. 启动 iPhone设置(Settings)菜单并选择屏幕时间(Screen Time)。
2. 选择内容和隐私限制(Content & Privacy Restrictions)。
3. 在允许更改(Allow Changes)部分，选择后台应用程序活动(Background App Activities)。
4. 选择允许(Allow)并检查是否可以在设置菜单中启用后台刷新。
是否禁用后台应用程序刷新(Disable Background App Refresh)？
后台刷新可能会导致应用程序快速耗尽 iPhone 的电池电量，但情况并非总是如此。在禁用Background App Refresh之前，您应该检查哪些应用程序正在后台主动运行，以及它们对 iPhone 电池的个别影响。
转到设置(Settings )>电池( Battery)并滚动到应用程序的电池使用情况(Battery Usage By App)部分。单击(Click)列表中的任何应用程序，您将找到应用程序的屏幕和后台活动的详细信息。仔细浏览列表并检查每个应用程序的后台活动范围。
如果您几乎不使用的应用程序长时间在后台持续运行，请为该应用程序禁用后台应用程序刷新(Background App Refresh)。根据经验，关闭后台刷新不会对应用程序的性能或功能产生任何不利影响。所以你没有什么可担心的。
除了禁用后台刷新之外，您还可以通过降低屏幕亮度、使用低功耗模式(using Low Power Mode)以及关闭某些应用的定位来延长 iPhone 或 iPad 的电池寿命。(extend your iPhone or iPad’s battery life)如果可能，请始终使用 Wi-Fi；Wi-Fi 通过蜂窝网络/移动数据使用更少的电力。
What Is Background App Refresh On iPhone?
When using an app on yoυr iPhone, iOS recognizes the app as “active”. When уou switch to another app, press the Home button, swipe to the homepage, or lock yоur iPhone, iOS ѕuspеnds applicatiоns to the background.
Despite being in a suspended state, some apps can still use your mobile data, Wi-Fi, and location/GPS services. But only if you allow them. In this article, we’ll explain what Background App Refresh is, plus how you can use the feature to manage apps using device resources in the background.
What is Background App Refresh?
Previously, only system apps and services could run in the background. Things changed with iOS 7 in 2013—Background App Refresh was introduced. Apple opened the background activity access to third-party app developers and equally put end users in the driving seats.
Allowing apps run in the background comes with its benefits: You get fresh and up-to-date content each time you reopen the app. But there’s the issue of battery drainage and excessive data consumption, especially if you’re using an internet plan with a data cap/limit.
The Background App Refresh feature helps iPhone and iPad users solve these problems. If you find that your iPhone’s battery drains faster than usual, disabling background refresh might help.
Note: Background refresh only works for active apps suspended in the background. Closed applications or apps that you quit from the app launcher will not refresh their content, even if Background App Refresh is enabled for the app(s). You’d need to wait for a newly-opened app to refresh its content with updated information.
How to Enable and Disable Background App Refresh
Background App Refresh is active by default on iPhones and iPads. This means that suspended apps will always check for new content in the background. You can manage what apps use this background refresh feature by navigating to Settings > General > Background App Refresh.
Apple lets you customize how Background App Refresh works based on the type of internet connection your device uses. You can configure apps to background-refresh their content all the time (i.e. with Wi-Fi & Mobile Data) or only via Wi-Fi connections. Select Off if you want to disable background refresh for all apps.
You can also turn off background refresh for individual apps; simply toggle off the switch next to the app in the Background App Refresh settings menu.
Another way to enable background refresh for an app is to go to the app’s settings menu (Settings > App Name) and toggle on Background App Refresh.
If this option is greyed out, return to the Background App Refresh menu and make sure background refresh is enabled for Wi-Fi & Mobile Data. Should background app refresh remain greyed out, proceed to the next section for more solutions.
iPhone Background App Refresh Greyed Out? 2 Ways to Fix
If you can’t enable Background App Refresh on your iPhone or iPad, we’ve compiled some possible solutions to the problem.
1. Disable Low Power Mode
Low Power Mode helps to maximize your iPhone’s battery life by suspending apps and system processes that consume excessive battery juice. Low Power Mode temporarily disables features like iCloud Photos, Background App Refresh, automatic downloads, animated wallpapers, etc.
iOS automatically disables Low Power Mode when you charge your phone up to 80% or higher. You can also manually disable the feature from the Control Center or settings menu. To turn off Low Power Mode, open the Control Center and tap the yellow battery icon.
If the battery icon is missing from the Control Center, go to Settings > Battery and toggle off Low Power Mode.
2. Disable Screen Time Restriction for Background Refresh
Screen Time has a content management and privacy section that lets you prevent third-parties from making unauthorized changes to your iPhone apps and settings. If you have a Screen Time restriction on your iPhone, make sure you haven’t blocked Background App Refresh. Here’s how to check.
1. Launch the iPhone Settings menu and select Screen Time.
2. Select Content & Privacy Restrictions.
3. In the Allow Changes section, select Background App Activities.
4. Select Allow and check if you can enable background refresh in the settings menu.
To Disable Background App Refresh or Not?
Background refresh may cause apps to rapidly deplete your iPhone’s battery juice, but that’s not always the case. Before disabling Background App Refresh, you should check which apps are actively running in the background and their individual impact on your iPhone’s battery.
Go to Settings > Battery and scroll to Battery Usage By App section. Click on any app on the list and you’ll find details of an app’s on-screen and background activity. Go through the list carefully and examine the background activity span of each app.
If an app that you barely use is constantly running in the background for a long period, disable Background App Refresh for the application. From experience, turning off background refresh doesn’t have any adverse effect on an app’s performance or functionality. So you have nothing to worry about.
Aside from disabling background refresh, you can also extend your iPhone or iPad’s battery life by reducing screen brightness, using Low Power Mode, and turning off location for certain apps. If possible, use Wi-Fi at all times; Wi-Fi uses less power over cellular network/mobile data.
