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Last Updated: Apr 24, 2024
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File Picker in Flutter

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Introduction

In mobile app development, Flutter has emerged as a powerful framework for building cross-platform applications with rich user interfaces and seamless performance. One of the essential components in many mobile apps is the file picker, enabling users to select files from their device's storage.

File picker in flutter

File Picker in Flutter

With the help of a file picker, users select files from their device's file system within an application. As a versatile framework, Flutter offers different third-party packages that simplify file selection. These packages provide ready-to-use widgets and APIs that facilitate browsing and selecting files from various sources, such as local, cloud, or external storage.

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Filepicker flutter tool

The Filepicker Flutter Tool is a command-line interface (CLI) tool designed to simplify the process of integrating file picking functionality into Flutter projects. It provides developers with a streamlined way to add file picker capabilities to their Flutter applications, allowing users to select files from various sources such as the device's storage, cloud services, or external drives. By using the Filepicker Flutter Tool, developers can efficiently manage file selection and integration tasks, saving time and effort in the development process.

1. File_picker

File_picker is a Flutter plugin that provides cross-platform support for picking files from the device's storage. It allows users to browse and select files such as images, videos, documents, and more. The File_picker plugin offers a simple and intuitive API for accessing file picking functionality in Flutter applications, making it easy for developers to incorporate file selection features into their projects.

2. Desktop_drop

Desktop_drop is a Flutter plugin specifically designed for desktop platforms (Windows, macOS, Linux) to enable drag-and-drop functionality. It allows users to drag files from their desktop environment and drop them into a Flutter application for processing. This plugin enhances the user experience by providing a seamless way to import files into desktop Flutter applications, facilitating intuitive interactions with the application's content.

3. File_selector

File_selector is a Flutter plugin that provides a platform-agnostic interface for selecting files from the device's storage. It abstracts the underlying platform-specific file selection mechanisms, allowing developers to write code that works across different platforms seamlessly. The File_selector plugin simplifies file picking implementation in Flutter applications, ensuring consistency and reliability across various operating systems.

4. Path_provider

Path_provider is a Flutter plugin that simplifies access to platform-specific directories such as the application's documents directory, cache directory, and temporary directory. It provides a unified API for retrieving file system paths on different platforms, enabling Flutter applications to access and manage files stored in these directories. The Path_provider plugin is essential for file handling tasks in Flutter apps, offering convenient access to file system paths for reading, writing, and manipulating files.

5. File_chooser

File_chooser is a Flutter plugin that extends the file picking capabilities to desktop platforms (Windows, macOS, Linux). It provides a platform-specific file chooser dialog for selecting files from the device's storage. The File_chooser plugin enhances the user experience in desktop Flutter applications by offering a familiar and native file selection interface, ensuring compatibility and consistency across different desktop operating systems.

Applications of File Picker

File picker functionality is essential in many scenarios across different types of applications. We have listed a few useful instances:

Document Processing

Applications that involve document editing, sharing, or storage often require the ability to select specific files from the user's device. Users can easily browse and select the required documents using the File Picker.

Media Management

Users can select media files like images, videos, or audio files for further processing or playback for apps like video players or image viewers with the help of File Picker.

File Uploading

In applications that involve file uploading to servers or cloud storage, a File Picker is a fundamental component. It allows users to choose files from their device's storage and initiates the uploading process seamlessly.

Implementing File Picker

Let’s explore the basic implementation of the File picker in Flutter. We are using VS Code as IDE, where we have installed the Flutter extension. To show the output, we will use the emulator from Android Studio. The below implementation is for selecting a single file from our local storage and displaying its name on the screen.

Create an App in Flutter

The first step is to create a Flutter application. It can be done by typing the below command in the terminal. For best practices, create a separate folder for such applications. After the Flutter file is created, we can open it using VS Code or Android Studio.

Command

flutter create app_name

Create layout UI

We should first plan and create a basic front end for our application. Below is the command for basic UI. Here we have kept a button at the center, which can be used after importing the material package in Flutter. All these codes will be written and edited in lib/main.dart, so remove the existing code and paste the below code. For more information about layouts, read this blog.

Code

import 'package:flutter/material.dart';

void main() {
	runApp(FilePickerApp());
}

class FilePickerApp extends StatefulWidget {
	@override
	_FilePickerAppState createState() => _FilePickerAppState();
}

class _FilePickerAppState extends State<FilePickerApp> {
	String fileName = '';

	@override
	Widget build(BuildContext context) {
   		return MaterialApp(
 			home: Scaffold(
				appBar: AppBar(
 					title: Text('File Picker Example'),
				),
				backgroundColor: Colors.cyan,
				body: Center(
					child: Column(
						mainAxisAlignment: MainAxisAlignment.center,
						children: [
							ElevatedButton(
								onPressed: _pickFile,
								child: Text('Pick a File'),
							),
							SizedBox(height: 20),
							Text(
								'Selected File: $fileName',
								style: TextStyle(fontSize: 18),
							),
						],
					),
				),
			),
		);
	}
}

 

Output

start page

Add the package for File Picker

Now, open the terminal inside the Flutter application and run the below command to add the File picker package.

Command

flutter pub add file_picker

Import the above package

To use the above package in our dart file, the below code must be added to import them.

Code

import 'package:file_picker/file_picker.dart';

Function to pick the files from storage

Now we will create a function that contains the logic to pick files with the help of the File Picker. The below code does the same. Here, the fileName state variable is updated with the name of the selected file by splitting the file path and retrieving the last segment. It is an asynchronous function, as it will take time to pick the files. So await is used for the FilePicker object as it will pick the files and return them to filePath variable. 

Code

void _pickFile() async {
	String? filePath = await FilePicker.platform
		.pickFiles(
			type: FileType.any,
		)
		.then((result) => result?.files.single.path);

	if (filePath != null) {
		setState(() {
			fileName = filePath.split('/').last;
		});
	}
 }

Final Code

Now our main.dart will look like the below-written code. We have added the _pickFile function at the onPressed event of the material button as a callback function. So, whenever it is pressed, the _pickFile will be triggered.

Code

import 'package:file_picker/file_picker.dart';
import 'package:flutter/material.dart';

void main() {
	runApp(FilePickerApp());
}

class FilePickerApp extends StatefulWidget {
	@override
	_FilePickerAppState createState() => _FilePickerAppState();
}

class _FilePickerAppState extends State<FilePickerApp> {
	String fileName = '';

	void _pickFile() async {
		String? filePath = await FilePicker.platform
			.pickFiles(
				type: FileType.any,
			)
			.then((result) => result?.files.single.path);

		if (filePath != null) {
			setState(() {
				fileName = filePath.split('/').last;
			});
		}
 	}

 	@override
 	Widget build(BuildContext context) {
		return MaterialApp(
			home: Scaffold(
				appBar: AppBar(
					title: Text('File Picker Example'),
				),
				backgroundColor: Colors.cyan,
				body: Center(
					child: Column(
						mainAxisAlignment: MainAxisAlignment.center,
						children: [
							ElevatedButton(
								onPressed: _pickFile,
								child: Text('Pick a File'),
							),
							SizedBox(height: 20),
							Text(
								'Selected File: $fileName',
								style: TextStyle(fontSize: 18),
							),
						],
					),
				),
			),
		);
	}
}

 

Output

Storage page  final output

Example file_picker App

The file_picker package in Flutter allows developers to easily integrate file picking functionality into their applications. An example app using file_picker typically includes features such as single file selection, multiple file selection, filtering by file extension, and displaying details of selected files.

Single File Picker

In a single file picker scenario, the user can select only one file from their device's storage. The app provides a button or UI element to trigger the file picker, and once the user selects a file, its details are displayed or processed accordingly.

Multiple File Picker

In a multiple file picker scenario, the user can select multiple files from their device's storage. The app provides a way for the user to select multiple files, such as checkboxes or a multi-select interface. After the user makes their selections, the app processes or displays the details of the selected files.

Pick a Particular File Extension

The file_picker package allows developers to filter file selections based on file extensions. This feature is useful when the app only needs files of a particular type, such as images, videos, documents, etc. The user interface typically includes options for specifying the desired file extension(s), and the file picker only displays files with matching extensions.

Selected File Details

Once the user selects one or more files using the file picker, the app can display details of the selected files. These details may include the file name, size, type, modification date, and other relevant metadata. The app can then use this information for further processing or display it to the user for confirmation before proceeding with file operations.

Supported Features

The "Supported Features" section provides an overview of the capabilities and functionalities offered by the file_picker package in Flutter. It lists the various features supported by the package, such as:

  1. Single File Selection: Users can select a single file from their device's storage.
  2. Multiple File Selection: Users can select multiple files at once.
  3. File Filtering: Users can filter files based on file extensions or other criteria.
  4. File Details: Details of selected files, such as name, size, type, etc., can be retrieved.
  5. Platform Compatibility: The package supports multiple platforms, including iOS, Android, web, and desktop (Windows, macOS, Linux).
  6. Customization: Developers can customize the file picker UI and behavior according to their app's requirements.
  7. Error Handling: The package provides robust error handling mechanisms to deal with various file selection scenarios.

Compatibility Chart

The "Compatibility Chart" provides a visual representation or tabular summary of the file_picker package's compatibility across different platforms and Flutter versions. It typically includes information such as:

  1. Supported Platforms: iOS, Android, web, desktop (Windows, macOS, Linux).
  2. Supported Flutter Versions: The range of Flutter versions with which the package is compatible.
  3. Supported Features: A list of features supported on each platform, such as single file selection, multiple file selection, file filtering, etc.
  4. Notes or Limitations: Any specific notes or limitations related to platform-specific implementations or behavior.

Frequently Asked Questions

What is the file picker limit in Flutter?

File picker in Flutter has no inherent limit on the number of files that can be selected, but it may depend on device capabilities and system resources.

What is the difference between file picker and image picker Flutter?

File picker allows selecting any type of file from storage, while image picker specifically selects images from the device's gallery or camera.

Is the file picker functionality available for both Android and iOS in Flutter?

Yes, the file picker functionality is available for both Android and iOS platforms in Flutter. 

Are there any security considerations when implementing the File picker in Flutter?

When implementing File picker functionality, it's essential to consider security and privacy. Handle selected files securely, validate user input, and follow best practices for storing and transmitting sensitive user data. 

Can I restrict the file types selected using the File picker in Flutter?

Yes, we can restrict the file types that users can select using File picker packages in Flutter. Most packages allow us to specify the allowed file extensions or MIME types when launching the file picker.

Can I select multiple files using the File picker in Flutter?

Yes, we can select multiple files using File Picker in Flutter. For instance, using the file_picker package, we can set the allowMultiple parameter to true when invoking the file picker function, allowing users to select multiple files simultaneously.

Conclusion

This article discussed the File Picker in Flutter and its implementation. It simplifies selecting files from a user's device within Flutter applications. By leveraging file picker packages, developers can enhance the user experience and streamline various aspects of their apps that involve file manipulation or management. Remember, Flutter offers several file picker packages, and the example provided in this article utilizes the file_picker.
 

Feel free to explore our other related articles:


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Topics covered
1.
Introduction
2.
File Picker in Flutter
3.
Filepicker flutter tool
3.1.
1. File_picker
3.2.
2. Desktop_drop
3.3.
3. File_selector
3.4.
4. Path_provider
3.5.
5. File_chooser
4.
Applications of File Picker
4.1.
Document Processing
4.2.
Media Management
4.3.
File Uploading
5.
Implementing File Picker
5.1.
Create an App in Flutter
5.2.
Create layout UI
5.3.
Add the package for File Picker
5.4.
Import the above package
5.5.
Function to pick the files from storage
5.6.
Final Code
6.
Example file_picker App
6.1.
Single File Picker
6.2.
Multiple File Picker
6.3.
Pick a Particular File Extension
6.4.
Selected File Details
7.
Supported Features
8.
Compatibility Chart
9.
Frequently Asked Questions
9.1.
What is the file picker limit in Flutter?
9.2.
What is the difference between file picker and image picker Flutter?
9.3.
Is the file picker functionality available for both Android and iOS in Flutter?
9.4.
Are there any security considerations when implementing the File picker in Flutter?
9.5.
Can I restrict the file types selected using the File picker in Flutter?
9.6.
Can I select multiple files using the File picker in Flutter?
10.
Conclusion