Hello I've run into this problem which is most probably my fault but any help/advice would be great.
I've got this piece of code which I run after user pushes the button, it does take text from the Textarea and it should create a text file inside appsDir for later usage.

//listen to tap
btn1.addEventListener("click",function(){
    var text = txtfd.value;

    if(text !== null)
    {
        var f = Titanium.Filesystem.createFile("test.txt");
             f.createFile();
            f.write(text);
            if(f.exists())
            {
                 alertDialog = Titanium.UI.createAlertDialog({
                    title: 'Be Happy!',
                    message: 'File exists!',
                    buttonNames: ['Yeah!']
                });
                alertDialog.show();
            }
            else
            {
                  alertDialog = Titanium.UI.createAlertDialog({
                    title: 'Be Worried!',
                    message: 'File does not exist!',
                    buttonNames: ['Doh!']
                });
                alertDialog.show();
            }
    }
});