CodeBlanks Logo Icon CodeBlanks
Login Register

What are permissions?

Learn the mobile app permissions concept.

What are permissions?

A permission is the operating system's approval gate for accessing a resource. Sensitive data like camera, location, notifications cannot be used by the app alone; the user must explicitly consent. The first request appears as a system dialog.

Permissions are required for security and privacy. Users do not want an app to access something without knowing. Once granted the app can use that resource; if denied it cannot. iOS and Android have slightly different permission flows; React Native and Expo wrap these differences under a common API with expo-permissions. This way one code works on both platforms.

The system dialog

When a permission is requested for the first time the operating system shows a system dialog. This dialog is controlled by the system, not the app; its design cannot be changed. The user picks 'Allow' or 'Deny'; this choice persists. Asking for the same permission again will not show the dialog; the last choice is remembered.

After a denial, asking again requires routing to settings. This is why a good flow asks for permission right at the moment of use, not before. Asking when the user taps 'Open camera' is less intrusive than asking at launch. This keeps user trust. If a permission is denied, showing an alternative message is also good.

Practice Write checkPermission

Write a checkPermission function. It takes a status parameter. If status === 'granted' it returns true; otherwise false.

Starter code

App.js
// Write the checkPermission function
// Take status parameter; true if 'granted', else false

Sample solution

App.js
function checkPermission(status) {
  if (status === "granted") {
    return true;
  }
  return false;
}

Questions and answers

Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.

1 Which needs a permission?

App.js
Permissions.askAsync(Permissions.CAMERA);
  • Showing Text
  • Using the camera Correct answer
  • Changing style
  • Pressing a button

Explanation: Using the camera needs a permission.

2 Camera without permission

Question 
// Without permission the ____ can't open
Answer 
// Without permission the camera can't open

Explanation: The camera cannot open without permission.

3 Match each concept to its role

Term Meaning
permission Approval gate
system dialog First request
camera Sensitive resource
deny No access

All lessons in Intermediate

1 Hooks

  1. useEffect
  2. Dependency array
  3. Cleanup
  4. useRef
  5. useMemo
  6. Summary - Hooks

2 Custom hooks

  1. Custom hook
  2. useToggle
  3. useCounter
  4. usePrevious
  5. Hook composition
  6. Summary - Custom hooks

3 Context

  1. What is Context?
  2. createContext
  3. Provider
  4. useContext
  5. Context default
  6. Summary - Context

4 Project: Notes app

  1. Project design
  2. Note model
  3. Adding notes
  4. AsyncStorage
  5. Putting it together

5 useReducer

  1. useReducer
  2. Reducer function
  3. Action dispatch
  4. Initial state
  5. useReducer vs useState
  6. Summary - useReducer

6 Form handling

  1. Controlled form
  2. Form state
  3. Validation
  4. Submit
  5. Form libraries
  6. Summary - Form handling

7 API and fetch

  1. fetch
  2. GET request
  3. async/await
  4. JSON parse
  5. Error handling
  6. Summary - API and fetch

8 Project: Quiz app

  1. Quiz model
  2. Loading questions
  3. Running the quiz
  4. Score calculation
  5. Putting it together

9 Tab navigation

  1. Bottom Tabs
  2. createBottomTabNavigator
  3. Tab icons
  4. Material Top Tabs
  5. Tab badge
  6. Summary - Tab navigation

10 Drawer navigation

  1. Drawer navigator
  2. createDrawerNavigator
  3. Drawer items
  4. Drawer toggle
  5. Nested navigation
  6. Summary - Drawer navigation

11 Lifecycle

  1. Mount
  2. Update
  3. Unmount
  4. useEffect lifecycle
  5. Layout effect
  6. Summary - Lifecycle

12 Project: E-commerce

  1. Project design
  2. Product list
  3. Product detail
  4. Cart
  5. Putting it together

13 Animated

  1. Animated.Value
  2. Animated.View
  3. Animated.timing
  4. Animated.spring
  5. interpolate
  6. Summary - Animated

14 Gestures

  1. PanResponder
  2. onMoveShouldSetPanResponder
  3. onPanResponderMove
  4. onPanResponderRelease
  5. react-native-gesture-handler
  6. Summary - Gestures

15 Theme

  1. Light/dark theme
  2. Theme context
  3. Theme toggle
  4. useColorScheme
  5. Persistent theme
  6. Summary - Theme

16 Performance

  1. React.memo
  2. useCallback
  3. useMemo
  4. FlatList optimization
  5. InteractionManager
  6. Summary - Performance

17 Testing

  1. Jest
  2. React Native Testing Library
  3. render
  4. getByText
  5. fireEvent
  6. Summary - Testing

18 Dev tools

  1. Flipper
  2. React DevTools
  3. Console
  4. Remote debug
  5. Performance monitor
  6. Summary - Dev tools

19 Permissions

  1. What are permissions?
  2. expo-permissions
  3. Camera permission
  4. Location permission
  5. Notification permission
  6. Summary - Permissions

20 Intermediate final

  1. Project design
  2. Context and hooks
  3. API integration
  4. Navigation
  5. Putting it together