android, How to rename a file?

In your code:

Shouldn’t it be :

File from = new File(directory, currentFileName);

instead of

File from = new File(directory, "currentFileName");

---

For safety,

Use the File.renameTo() . But check for directory existence before renaming it!

File dir = Environment.getExternalStorageDirectory();
if(dir.exists()){
    File from = new File(dir,"from.mp4");
    File to = new File(dir,"to.mp4");
     if(from.exists())
        from.renameTo(to);
}

Refer:
http://developer.android.com/reference/java/io/File.html#renameTo%28java.io.File%29