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

The problem is in this line,

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

Here currentFileName is actually a String you dont have to use "

try it this way,

File from      = new File(directory, currentFileName  );
                                    ^               ^         //You dont need quotes

Use this method to rename a file. The file from will be renamed to to.

private boolean rename(File from, File to) {
    return from.getParentFile().exists() && from.exists() && from.renameTo(to);
}

Example code:

public class MainActivity extends Activity {
    private static final String TAG = "YOUR_TAG";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        File currentFile = new File("/sdcard/currentFile.txt");
        File newFile = new File("/sdcard/newFile.txt");

        if (rename(currentFile, newFile)) {
            //Success
            Log.i(TAG, "Success");
        } else {
            //Fail
            Log.i(TAG, "Fail");
        }
    }

    private boolean rename(File from, File to) {
        return from.getParentFile().exists() && from.exists() && from.renameTo(to);
    }
}