Thursday, March 28, 2024

Image Picker plugin for Flutter

A Flutter plugin for iOS and Android for picking images from the image library, and taking new pictures with the camera.

Installation

First, add image_picker as a dependency in your pubspec.yaml file.

iOS

Add the following keys to your Info.plist file, located in /ios/Runner/Info.plist:

  • NSPhotoLibraryUsageDescription – describe why your app needs permission for the photo library. This is called Privacy – Photo Library Usage Description in the visual editor.
  • NSCameraUsageDescription – describe why your app needs access to the camera. This is called Privacy – Camera Usage Description in the visual editor.
  • NSMicrophoneUsageDescription – describe why your app needs access to the microphone, if you intend to record videos. This is called Privacy – Microphone Usage Description in the visual editor.

Android

No configuration required – the plugin should work out of the box.

Example

import 'package:image_picker/image_picker.dart';

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  File _image;

  Future getImage() async {
    var image = await ImagePicker.pickImage(source: ImageSource.camera);

    setState(() {
      _image = image;
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Image Picker Example'),
      ),
      body: Center(
        child: _image == null
            ? Text('No image selected.')
            : Image.file(_image),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: getImage,
        tooltip: 'Pick Image',
        child: Icon(Icons.add_a_photo),
      ),
    );
  }
}

Handling MainActivity destruction on Android

Android system — although very rarely — sometimes kills the MainActivity after the image_picker finishes. When this happens, we lost the data selected from the image_picker. You can use retrieveLostData to retrieve the lost data in this situation. For example:

Future<void> retrieveLostData() async {
  final LostDataResponse response =
      await ImagePicker.retrieveLostData();
  if (response == null) {
    return;
  }
  if (response.file != null) {
    setState(() {
      if (response.type == RetrieveType.video) {
        _handleVideo(response.file);
      } else {
        _handleImage(response.file);
      }
    });
  } else {
    _handleError(response.exception);
  }
}

There’s no way to detect when this happens, so calling this method at the right place is essential. We recommend to wire this into some kind of start up check. Please refer to the example app to see how we used it.

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