Download file inside WebView from android 13 – Android

The Problem:

In my Android (13) application, I have a WebView that allows users to browse the internet. When users click on a link to download a file, the download does not start. I have already implemented the necessary permissions, including WRITE_EXTERNAL_STORAGE, READ_EXTERNAL_STORAGE, READ_MEDIA_VIDEO, READ_MEDIA_AUDIO, READ_MEDIA_IMAGES, ACCESS_NETWORK_STATE, ACCESS_WIFI_STATE, WRITE_EXTERNAL_STORAGE, DOWNLOAD_WITHOUT_NOTIFICATION, and ACCESS_DOWNLOAD_MANAGER. Strangely, if I switch to the default Android browser, the downloads work as expected. How can I enable file downloads within my WebView in Android 13?

The Solutions:

Solution 1: Permission handling and cookies consideration

1. Permission Handling:

• For Android devices running API level 29 and above, you don’t need to request the WRITE_EXTERNAL_STORAGE permission to download files to the shared Downloads directory.
• For devices running API level 28 and below, you need to declare the WRITE_EXTERNAL_STORAGE permission in your manifest and handle the permission request result.

2. Download Logic:

• Use the setDownloadListener on the WebView to listen for download requests.
• Parse the URL string to a Uri object.
• Extract the file name and extension from the URL.
• Construct a DownloadManager.Request object and set appropriate parameters like destination directory, notification visibility, and user-agent.
• Add cookies to the request header if necessary.
• Start the download using the DownloadManager.

3. Cookies Handling:

• Use the CookieManager to get cookies from the WebView.
• If cookies are available, add them to the DownloadManager.Request header.

4. Handling API Level Differences:

• To support API level 28 and below, handle the permission request result and display an appropriate dialog if the permission is denied.
• Check for cookies and display an error dialog if they are not available in certain WebView versions.

5. Implementation:

• The provided Git repository offers a complete working example.

Key Points:

• Permission handling is crucial for devices running API level 28 and below.
• Use the CookieManager to handle cookies when downloading files requiring authentication.
• The implementation provided in the Git repository provides a comprehensive solution.

Solution 2: Utilize WebView’s Download Listener

Android 13 introduced a new download listener for web views, allowing for seamless file downloads from within the WebView itself. Here’s how you can implement it:

1. Implement the DownloadListener:
   Add the following code to your Activity or Fragment that contains the WebView:

binding.webView.setDownloadListener { url, _, _, _, _ ->
    // Trigger the download of the file
    binding.webView.loadUrl(url)
}

• The setDownloadListener method accepts a DownloadListener interface as an argument.
• Inside the onDownloadStart method, the url parameter represents the URL of the file to be downloaded.
• loadUrl(url) method initiates the download process by loading the file’s URL in the WebView.

2. Request Necessary Permissions:
   Ensure that you have declared the necessary permissions in your app’s manifest file:

• WRITE_EXTERNAL_STORAGE: To save the downloaded file to the device’s storage.
• READ_EXTERNAL_STORAGE: To access the device’s storage for saving the file.

3. Handle Downloaded Files:
   Once the file is downloaded, you can handle it further, such as displaying a notification or opening it in an appropriate application. You can do this by overriding the onReceive method in a BroadcastReceiver and listening for the ACTION_DOWNLOAD_COMPLETE intent.

4. Additional Tips:

• You can customize the location where the file is saved by creating a DownloadManager object and setting the destination directory.
• For larger downloads, you may want to display a progress bar or provide feedback to the user.
• You can also use third-party libraries that provide additional features and customization options for file downloads in WebView.

This approach allows for a seamless file download experience within the WebView, without requiring the user to leave the app or switch to another browser.

Video Explanation: