iOS Simulator
The iOS Simulator lets you test your app on a virtual iPhone or iPad on your Mac. It’s your primary tool for seeing your app in action.What is the Simulator?
The Simulator is a virtual iOS device running on your Mac. It:- Runs your actual compiled app
- Simulates iPhone/iPad hardware
- Supports most iOS features
- Updates instantly as you build
How It Works with Nativeline
- You make changes via chat
- Nativeline rebuilds your app
- App automatically launches in Simulator
- You test and iterate
Interacting with the Simulator
Basic Interactions
| Action | How to Do It |
|---|---|
| Tap | Click |
| Scroll | Click and drag, or two-finger swipe |
| Swipe | Click and drag |
| Long press | Click and hold |
| Pinch/zoom | Option + drag |
| Rotate | Cmd+Left/Right Arrow |
| Shake | Device → Shake |
Text Input
Click a text field and type with your keyboard. The Simulator uses your Mac’s keyboard.Home Screen
- Home button: Cmd+Shift+H
- Home (iPhone X+): Drag up from bottom
Changing Devices
You can test on different iPhone/iPad models:In Nativeline
Look for device selection in the toolbar or settings.In Simulator
- File → Open Simulator
- Choose a device type
Why Different Devices?
| Device | Best For Testing |
|---|---|
| iPhone SE | Small screens, compact layouts |
| iPhone 15 | Standard size, typical user |
| iPhone 15 Pro Max | Large screens, edge cases |
| iPad | Tablet layouts |
Simulator Features
Location Simulation
Test location features without moving:- Features → Location
- Choose: City Bicycle Ride, Freeway Drive, Custom Location
- Features → Location → Custom Location
- Enter latitude/longitude
Screenshots
Save screenshots of your app:- Cmd+S while Simulator is focused
- Saved to Desktop by default
Screen Recording
Record your app in action:- File → Record Screen
- Interact with your app
- Stop recording
- Video saved to Desktop
Dark Mode Toggle
Quick appearance switch:- Features → Toggle Appearance
- Or: Settings app → Display & Brightness
Keyboard Toggle
Show/hide the software keyboard:- Cmd+K
- Or: I/O → Keyboard → Toggle Software Keyboard
First Launch
The first time the Simulator boots:- Takes 30-60 seconds
- Downloads iOS components
- Creates virtual device
What the Simulator Can’t Do
Some features require a real device:| Not Available | Alternative |
|---|---|
| Actual camera | Use photo library |
| Real GPS | Simulated locations |
| Face ID sensor | Simulated Face ID (Features menu) |
| Actual push notifications | Local notifications work |
| Apple Pay | Simulated in sandbox |
| Real performance | Test on device for speed |
Performance Considerations
Simulator vs Real Device
The Simulator is:- Faster for some things (uses Mac’s powerful CPU)
- Slower for others (graphics aren’t optimized)
- Not accurate for performance testing
Improving Simulator Performance
If the Simulator is slow:- Use a simpler device (iPhone SE instead of Pro Max)
- Close other Simulators
- Close other heavy apps
- Restart the Simulator
Common Simulator Tasks
Reset to clean state
Reset to clean state
Device → Erase All Content and SettingsThis clears:
- All app data
- All permissions
- All settings
Add photos to test with
Add photos to test with
Drag image files from Finder onto the Simulator window. They’re added to the Photos app.
Simulate slow network
Simulate slow network
Use Network Link Conditioner (part of Additional Tools for Xcode):
- System Preferences → Network Link Conditioner
- Choose a profile (3G, Edge, etc.)
- Turn on
Test different iOS versions
Test different iOS versions
Xcode → Settings → Platforms → Download other iOS versionsThen create Simulators with those versions.
Troubleshooting
Simulator won't launch
Simulator won't launch
- Check Xcode is installed (Nativeline installs automatically)
- Restart Nativeline
- Open Xcode → Window → Devices and Simulators to check Simulator health
- Try: sudo killall -9 com.apple.CoreSimulator.CoreSimulatorService
App not appearing after build
App not appearing after build
- Check build succeeded (look for errors in chat)
- Simulator might be behind other windows
- Check other Spaces/Desktops
- The app might need to be manually launched from Simulator home screen
Simulator is very slow
Simulator is very slow
- Close other applications
- Use a simpler device
- Restart Simulator (Device → Restart)
- Restart your Mac
Keyboard not showing
Keyboard not showing
Press Cmd+K to toggle software keyboard, or:
I/O → Keyboard → Toggle Software Keyboard
Can't type in text fields
Can't type in text fields
- Click the text field first
- Make sure hardware keyboard is enabled: I/O → Keyboard → Connect Hardware Keyboard
Simulator Shortcuts
| Shortcut | Action |
|---|---|
| Cmd+Shift+H | Home |
| Cmd+Left/Right | Rotate |
| Cmd+K | Toggle keyboard |
| Cmd+S | Screenshot |
| Cmd+R | Reboot |
| Cmd+Shift+A | Toggle slow animations |