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How to download a file using Fast Networking Library in Kotlin Android

How to download a file using Fast Networking Library in Kotlin Android.

Here's a step-by-step tutorial on how to download a file using the Fast Networking Library in Kotlin for Android.

Step 1: Add Fast Networking Library to your project​

To begin, you need to add the Fast Networking Library to your project. Open your project's build.gradle file and add the following dependency to the dependencies block:

implementation 'com.amitshekhar.android:android-networking:1.0.2'

After adding the dependency, sync your project to fetch the library.

Step 2: Request permission to access the internet​

To download a file, you need to have the INTERNET permission in your AndroidManifest.xml file. Open the file and add the following line of code inside the manifest tag:

<uses-permission android:name="android.permission.INTERNET" />

Step 3: Add code to download the file​

Now, let's write the code to download a file using the Fast Networking Library. Open the file where you want to perform the download (e.g., MainActivity.kt) and add the following code:

AndroidNetworking.download("https://example.com/file.txt", getExternalFilesDir(null)?.absolutePath, "file.txt")
        .setPriority(Priority.MEDIUM)
        .build()
        .setDownloadProgressListener { bytesDownloaded, totalBytes ->
            // Update progress here if needed
            val progress = (bytesDownloaded * 100) / totalBytes
        }
        .startDownload(object : DownloadListener {
            override fun onDownloadComplete() {
                // File download completed
            }

            override fun onError(anError: ANError?) {
                // Handle error during download
            }
        })

Let's break down the code:

  • AndroidNetworking.download creates a download request by specifying the URL of the file to download, the directory to save the file (getExternalFilesDir(null)?.absolutePath in this example), and the filename.
  • setPriority sets the priority of the download. You can choose from HIGH, MEDIUM, or LOW.
  • build builds the download request.
  • setDownloadProgressListener sets a listener to track the progress of the download. Inside this listener, you can update the progress UI if needed.
  • startDownload starts the download and provides a callback using the DownloadListener interface. Inside the callback, you can handle the completion of the download or any errors that occur.

Step 4: Handle the downloaded file​

Once the file is downloaded successfully, you can handle it according to your requirements. For example, you can display it in a TextView or save it locally. Here's an example of saving the file locally:

val file = File(getExternalFilesDir(null), "file.txt")
val inputStream = FileInputStream(file)
val buffer = ByteArray(1024)
val bytesRead = inputStream.read(buffer)
val output = FileOutputStream(File(getExternalFilesDir(null), "newfile.txt"))
while (bytesRead >= 0) {
    output.write(buffer, 0, bytesRead)
}
output.close()

In this example, we read the downloaded file from the original file path and write it to a new file path.

That's it! You've successfully downloaded a file using the Fast Networking Library in Kotlin for Android. You can now use this knowledge to implement file downloads in your own Android projects.