Cordova App : How to get the actual path of file

I'm using Cordova to make android and iOS app, now I would like to check if file already exist in the dirctory.

First I download file from server and save it locally using the code below

$scope.downloadFile = function(){

        alert(cordova.file.dataDirectory)
        var fileTransfer = new FileTransfer();
        var uri = encodeURI("http://example.com/files/th/001.mp3");
        var downloadPath = cordova.file.dataDirectory+'001.mp3'; // ANDROID

        fileTransfer.download(
            uri,
            downloadPath,
            function(entry) {
                $scope.savepath = entry.toInternalURL();
                alert("download complete: " + entry.toURL());
                alert('saved at : '+entry.toInternalURL());
            },
            function(error) {
                alert("download error source " + error.source);
                alert("download error target " + error.target);
                alert("upload error code" + error.code);
            },
            false,
            {
                headers: {
                    "Authorization": "Basic dGVzdHVzZXJuYW1lOnRlc3RwYXNzd29yZA=="
                }
            }
        );
    }//End DownloadFile

and I would like to check if the file already exist using checkIfFileExists(path) method

function checkIfFileExists(path){
        window.requestFileSystem(LocalFileSystem.PERSISTENT, 0, function(fileSystem){
            //alert('result: '+JSON.stringify(fileSystem.root))
            fileSystem.root.getFile(path, { create: false }, fileExists, fileDoesNotExist);
        }, getFSFail); //of requestFileSystem
    }
    function fileExists(fileEntry){
        alert("File " + fileEntry.fullPath + " exists!");
    }
    function fileDoesNotExist(){
        alert("file does not exist");
    }
    function getFSFail(evt) {
        console.log(evt.target.error.code);
    }

I checked on my phone, the file is already saved to Android/data/com.myname.myappname/file/001.mp3

but the problem is the code always show file does not exist whenever I use the path like

cordova.file.dataDirectory+'001.mp3';

or cdvfile://localhost/persistent/files/001.mp3

or 'cdvfile://localhost/files/001.mp3'

so I would like to ask that the real path that I need to use to check if the file exist or not.

Please provide me any suggestion.

Regards.

Do you need to use or CheckFileExists? You could try using Phonegap's FileReader method?

var reader = new FileReader();
var fileSource = cordova.file.dataDirectory+'001.mp3'

reader.onloadend = function(evt) {

if(evt.target.result == null) {
   // Null? You still have a problem: file doesn't exist.
} else {
    // Otherwise the file exists. 
}         
};

//Check if the file exists
reader.readAsDataURL(fileSource);