Get the special file size which you know the file name
By Vikram
You also can get the specic one file size in filesystem. Do not forget add privilege
function getfilesize(){
var file;
var directory = '/opt/usr/media/Documents/';
tizen.filesystem.resolve(
directory,
function(dir){
file = dir.resolve("x.txt");
alert(file.fileSize);
},
function(e){console.log("error" + e.message)}, "rw");
}