iOS 模拟器
了解如何在 Mac 上安装 iOS 模拟器并使用它来开发应用。
直接在计算机上开发应用比不断与 iPhone 或 iPad 交互更方便，尤其是当网络条件较慢或由于 LAN 限制而需要 隧道连接 时。
¥Developing your app directly on a computer can be more convenient than constantly interacting with an iPhone or iPad, especially when network conditions are slow or when a tunnel connection is required due to LAN limitations.
本指南介绍了如何在 Mac 上安装 iOS 模拟器以进行应用开发。请注意，iOS 模拟器只能安装在 macOS 上。如果你要从 Windows 或 Linux 计算机开发 iOS 应用，则需要物理 iOS 设备。
¥This guide explains how to install the iOS Simulator on your Mac for app development. Note that the iOS Simulator can only be installed on macOS. If you are developing an iOS app from a Windows or a Linux machine, you will need a physical iOS device.
设置 Xcode 和 Watchman
¥Setup Xcode and Watchman
1
Install Xcode
Open up the Mac App Store, search for Xcode, and click Install (or Update if you have it already).
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Install Watchman
Watchman is a tool for watching changes in the filesystem. Installing it will result in better performance. You can install it with:
- brew update- brew install watchman4
Try it out
Run your app with npx expo start and press i from the command line.
You may get a warning about needing to accept the Xcode license. Run the command that it suggests. Open your app again to see if it was successful. If not, check the troubleshooting tips below.
You can also press shift + i in the Expo CLI to interactively select a simulator to open.
Expo Orbit
You can use the Expo Orbit app which allows launching builds and simulator management with one click from the menu bar on macOS.
了解有关如何使用 Expo Orbit 的更多信息。
Limitations
Although the iOS Simulator is great for rapid development, it does come with a few limitations. We'll list out a few of the main differences that affect Expo APIs below. However, see Apple's documentation for more details.
The following hardware is unavailable in the Simulator:
- Audio Input
- Barometer
- Camera
- Motion Support (accelerometer and gyroscope)
The Simulator also suspends background apps and processes on iOS 11 and later.
Troubleshooting
The CLI seems to be stuck when opening a Simulator
Sometimes the iOS Simulator doesn't respond to the open command. If it seems stuck on this prompt, you can open the iOS Simulator manually (open -a Simulator) and then in the macOS toolbar, choose File > Open Simulator, and select an iOS version and device that you'd like to open.
You can use this menu to open any version of the simulator. You can also open multiple simulators at the same time, however, Expo CLI will always target the most recently opened simulator.
Simulator opened but the Expo Go app isn't opening inside of it
The first time you install the app in the simulator, iOS will ask if you'd like to open the Expo Go app. You may need to interact with the simulator (click around, drag something) for this prompt to show up, then press OK.
How do I force an update to the latest version?
Create a project with the desired SDK version and open it in a simulator to install a particular version of Expo Go.
# Bootstrap an SDK 51 project- npx create-expo-app --template blank@51# Open the app on a simulator to install the required Expo Go app- npx expo start --iosExpo CLI is printing an error message about xcrun, what do I do?
For miscellaneous errors, try the following:
- Manually uninstall Expo Go on your simulator and reinstall by pressing shift + i in the Expo CLI Terminal UI and selecting the desired simulator.
- If that doesn't help, focus the simulator window and in the Mac toolbar choose Device > Erase All Content and Settings...
这将从空白图片重新初始化你的模拟器。这有时对于计算机内存不足且模拟器无法存储某些内部文件、使设备处于损坏状态的情况很有用。
¥This will reinitialize your simulator from a blank image. This is sometimes useful for cases where your computer is low on memory and the simulator fails to store some internal files, leaving the device in a corrupt state.