UNUserNotificationCenter.requestAuthorization()重复调用相关技术咨询

Great question! Let's break down each part of your query with clear, practical details:

1. 这个方法可以被多次调用吗？ #

Absolutely yes. There's no restriction on how many times you call requestAuthorization() — the system handles repeated calls gracefully without any issues.

2. 能在应用每次启动时调用该方法吗？ #

You bet. In fact, this is a common practice for many apps. When you call it on launch, even if the user has already made a choice about notifications, the completion handler will immediately return the current permission status. This is a quick way to confirm whether your app can send notifications right as the app starts up, instead of relying on cached state that might be outdated (like if the user changed permissions in Settings while your app was closed).

3. 用户已授予通知权限后，是否还能再次调用它？ #

Definitely. Here's what happens when you call it after the user has granted permission:

• The system won't show the permission prompt again (since the user's choice is stored persistently).
• The completion handler will fire right away, with granted: true (and no error, assuming everything works as expected).

Why is this allowed? #

The requestAuthorization() method isn't just for asking permission the first time — it also doubles as a way to check the current permission state (though Apple does provide getNotificationSettings(completionHandler:) specifically for that purpose). The system is designed to respect the user's existing choice, so repeated calls don't annoy the user with redundant prompts, but still let you get up-to-date permission info when you need it.

One quick note: If the user previously denied notification permissions, calling requestAuthorization() again won't trigger the prompt either. In that case, you should consider showing a friendly in-app message guiding the user to enable permissions in the system Settings app, instead of spamming the method call.

内容的提问来源于stack exchange，提问作者jaredsinclair