How to programmatically move, copy and delete file

Question

I want to programmatically move, copy and delete files and directories on SD card. I've done a Google search but couldn't find anything useful.

Answer 1

Function for moving files:

private void moveFile(File file, File dir) throws IOException {
    File newFile = new File(dir, file.getName());
    FileChannel outputChannel = null;
    FileChannel inputChannel = null;
    try {
        outputChannel = new FileOutputStream(newFile).getChannel();
        inputChannel = new FileInputStream(file).getChannel();
        inputChannel.transferTo(0, inputChannel.size(), outputChannel);
        inputChannel.close();
        file.delete();
    } finally {
        if (inputChannel != null) inputChannel.close();
        if (outputChannel != null) outputChannel.close();
    }

}

Answer 2

Use standard Java I/O. Use Environment.getExternalStorageDirectory() to get to the root of external storage (which, on some devices, is an SD card).

Answer 3

Moving file using kotlin. App has to have permission to write a file in destination directory.

@Throws(FileNotFoundException::class, IOError::class)
private fun moveTo(source: File, dest: File, destDirectory: File? = null) {

    if (destDirectory?.exists() == false) {
        destDirectory.mkdir()
    }

    val fis = FileInputStream(source)
    val bufferLength = 1024
    val buffer = ByteArray(bufferLength)
    val fos = FileOutputStream(dest)
    val bos = BufferedOutputStream(fos, bufferLength)
    var read = fis.read(buffer, 0, read)
    while (read != -1) {
        bos.write(buffer, 0, read)
        read = fis.read(buffer) // if read value is -1, it escapes loop.
    }
    fis.close()
    bos.flush()
    bos.close()

    if (!source.delete()) {
        HLog.w(TAG, klass, "failed to delete ${source.name}")
    }
}

Answer 4

1. Permissions:

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

2. Get SD card root folder:

   Environment.getExternalStorageDirectory()
   

3. Delete file: this is an example on how to delete all empty folders in a root folder:

   public static void deleteEmptyFolder(File rootFolder){
       if (!rootFolder.isDirectory()) return;
   
       File[] childFiles = rootFolder.listFiles();
       if (childFiles==null) return;
       if (childFiles.length == 0){
           rootFolder.delete();
       } else {
           for (File childFile : childFiles){
               deleteEmptyFolder(childFile);
           }
       }
   }
   

4. Copy file:

   public static void copyFile(File src, File dst) throws IOException {
       FileInputStream var2 = new FileInputStream(src);
       FileOutputStream var3 = new FileOutputStream(dst);
       byte[] var4 = new byte[1024];
   
       int var5;
       while((var5 = var2.read(var4)) > 0) {
           var3.write(var4, 0, var5);
       }
   
       var2.close();
       var3.close();
   }
   

5. Move file = copy + delete source file

Answer 5

Xamarin Android

public static bool MoveFile(string CurrentFilePath, string NewFilePath)
{
    try
    {
        using (var f = new File(CurrentFilePath))
        using (var i = new FileInputStream(f))
        using (var o = new FileOutputStream(NewFilePath))
        {
            i.Channel.TransferTo(0, i.Channel.Size(), o.Channel);
            f.Delete();
        }

        return true;
    }
    catch { return false; }
}

public static bool CopyFile(string CurrentFilePath, string NewFilePath)
{
    try
    {
        using (var i = new FileInputStream(CurrentFilePath))
        using (var o = new FileOutputStream(NewFilePath))
            i.Channel.TransferTo(0, i.Channel.Size(), o.Channel);

        return true;
    }
    catch { return false; }
}

public static bool DeleteFile(string FilePath)
{
    try
    {
        using (var file = new File(FilePath))
            file.Delete();

        return true;
    }
    catch { return false; }
}

Answer 6

Copy file using Square's Okio:

BufferedSink bufferedSink = Okio.buffer(Okio.sink(destinationFile));
bufferedSink.writeAll(Okio.source(sourceFile));
bufferedSink.close();