Camera plugin
- Flutter course
- Advanced
- Lesson 33/69
- 4 min
Build a live camera preview with the camera package.
The camera package
The camera package provides direct access to the device camera and lets you build a live preview. You initialize the camera with CameraController and display the feed with the CameraPreview widget. Unlike image_picker, it lets the user see the camera stream before capturing.
final controller = CameraController(camera, ResolutionPreset.high);
await controller.initialize();The CameraPreview widget
CameraPreview is the widget that displays the controller's live feed on screen. It is used as CameraPreview(controller). Using this widget before the controller is initialized throws an error.
CameraPreview(controller);Practice Initialize the controller and check it
Create a CameraController, initialize it with initialize and print controller.value.isInitialized.
Starter code
class CameraDescription {
final String name;
CameraDescription(this.name);
}
enum ResolutionPreset { low, medium, high }
class CameraValue {
final bool isInitialized;
CameraValue(this.isInitialized);
}
class CameraController {
final CameraDescription camera;
final ResolutionPreset resolution;
bool _initialized = false;
CameraController(this.camera, this.resolution);
CameraValue get value => CameraValue(_initialized);
Future<void> initialize() async {
_initialized = true;
}
}
void main() async {
// controller oluştur
// initialize çağır
// isInitialized yazdır
}Sample solution
class CameraDescription {
final String name;
CameraDescription(this.name);
}
enum ResolutionPreset { low, medium, high }
class CameraValue {
final bool isInitialized;
CameraValue(this.isInitialized);
}
class CameraController {
final CameraDescription camera;
final ResolutionPreset resolution;
bool _initialized = false;
CameraController(this.camera, this.resolution);
CameraValue get value => CameraValue(_initialized);
Future<void> initialize() async {
_initialized = true;
}
}
void main() async {
final controller = CameraController(
CameraDescription('0'),
ResolutionPreset.high,
);
await controller.initialize();
print(controller.value.isInitialized);
}Expected output
true
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 What is the main difference between the camera package and image_picker?
- They are completely identical
- The camera package only picks from the gallery
- The camera package provides a live camera preview Correct answer
- image_picker is faster
Explanation: The camera package provides a live camera stream and preview; image_picker only opens the system picker.
2 Initialize the controller
await controller.____;await controller.initialize();Explanation: Before using the CameraController you call the initialize method; it is asynchronous so await is required.
3 camera package parts
| Term | Meaning |
|---|---|
camera |
Camera access package |
CameraController |
Camera controller |
CameraPreview |
Live preview widget |
initialize |
Initialization method |