react-native-document-picker

The react-native-document-picker library is a React Native module that allows users to select documents (or files) from their device storage. This can include various types of files, such as images, videos, PDFs, audio files, and other types of documents, depending on the platform (iOS or Android).

The primary use case for this library is to give users the ability to pick files from their local storage or cloud services (like iCloud, Google Drive, etc.) within a React Native app.

Key Features of react-native-document-picker:

1. File Selection:
   • Allows users to pick various types of files (documents, images, audio, etc.) from their device storage.
   • Works across iOS and Android, providing a consistent API to access documents.
2. File Type Filtering:
   • You can specify the types of files you want users to select (e.g., only PDFs, only images, only audio files, etc.).
   • The library provides predefined constants for file types (e.g., DocumentPicker.types.images, DocumentPicker.types.audio, DocumentPicker.types.pdf), but you can also specify custom types.
3. Multiple File Selection:
   • You can allow the user to select multiple files at once (in supported platforms).
4. File Metadata:
   • After selecting a file, the library provides metadata about the file, such as its URI, name, size, type, and more, which you can use in your app.
5. Cross-platform:
   • Works on both iOS and Android devices, though there are some differences in behavior between the platforms, especially regarding the supported file types and the appearance of the file picker.

Basic Usage Example:

Here’s a simple example of how to use the react-native-document-picker library to allow a user to pick an audio file:

Import and Use the Library:Below is an example of how to use react-native-document-picker to allow the user to pick an audio file:

import React, { useState } from 'react';
import { View, Button, Text, Alert } from 'react-native';
import DocumentPicker from 'react-native-document-picker';

const FilePickerExample = () => {
  const [fileInfo, setFileInfo] = useState(null);

  // Function to pick an audio file
  const handlePickFile = async () => {
    try {
      // Pick an audio file
      const res = await DocumentPicker.pick({
        type: [DocumentPicker.types.audio],  // Filter for audio files
      });

      setFileInfo(res);  // Set the file metadata

      // Alert with file information
      Alert.alert('File Selected', `File: ${res.name}, Size: ${res.size} bytes`);

      console.log(res);  // Log the file metadata (URI, type, name, etc.)
    } catch (err) {
      if (DocumentPicker.isCancel(err)) {
        console.log('User canceled the picker');
      } else {
        console.error('Error picking file:', err);
      }
    }
  };

  return (
    <View style={{ flex: 1, justifyContent: 'center', alignItems: 'center' }}>
      <Button title="Pick an Audio File" onPress={handlePickFile} />
      {fileInfo && (
        <Text style={{ marginTop: 20 }}>
          File: {fileInfo.name} (Size: {fileInfo.size} bytes)
        </Text>
      )}
    </View>
  );
};

export default FilePickerExample;

Install the library:If you haven’t already, install the library by running:

npm install react-native-document-picker

Or if you're using yarn:

yarn add react-native-document-picker

File Metadata Example:

When a file is selected, the DocumentPicker.pick() method returns an object containing metadata about the file. Here is an example of the metadata you might get:

{
  uri: 'file:///storage/emulated/0/Download/song.mp3',
  type: 'audio/mp3',  // The MIME type of the file
  name: 'song.mp3',   // The file name
  size: 1234567,      // The size of the file in bytes
  fileCopyUri: 'content://com.android.providers.media.documents/document/...',
}

File Types:

react-native-document-picker supports many file types, and you can filter what type of files users can pick. Here are some of the predefined types available:

All Files (Generic for any file type):

DocumentPicker.types.allFiles

Spreadsheets (Excel files):

DocumentPicker.types.xls

Plain Text:

DocumentPicker.types.plainText

PDF Documents:

DocumentPicker.types.pdf

Audio:

DocumentPicker.types.audio

Images:

DocumentPicker.types.images

You can also combine multiple types. For example, to allow both images and audio:

type: [DocumentPicker.types.images, DocumentPicker.types.audio]

Key Methods:

• pick(): The main method used to open the file picker and select files. You can pass an object with options to specify file types and whether multiple files can be selected.
• pickMultiple(): Allows users to pick multiple files at once (iOS only).
• isCancel(): A utility method to check if the user canceled the file picking action.

Platform Differences:

• iOS: The library provides a native file picker. You can pick files from the local file system, including cloud services like iCloud Drive.
• Android: The library typically uses the device's file system picker, which may vary depending on the Android version and manufacturer. The file picker might not always show cloud storage options unless explicitly configured by the app.

Use Cases:

1. Allow users to upload documents, images, or audio files from their device to your app (e.g., for profile pictures, document submissions, etc.).
2. Cloud storage integration: Some Android versions may allow cloud storage access via the file picker, but for full cloud file support, you'll typically need to integrate with a specific cloud API (e.g., Google Drive, iCloud).
3. Handling PDFs or media files: If you need to open or process PDFs or media files (audio, video, etc.), this library helps by allowing users to select these files from their device.

Summary:

• What it does: react-native-document-picker enables users to select files from their local storage (including documents, images, and audio files) and provides metadata about the selected file.
• Why it's useful: It simplifies the process of file selection in React Native apps, providing a consistent interface across iOS and Android.

Let me know if you need more information or examples!