first time you open the game, load all the data into localstorage, then use local storage instead of xml. Every time you load the game, check if the data is loaded, if its loaded, then continue. Yes, its not the best thing but at least can work and the only bad thing is the load time of first time, but will be only bad if you must load A LOT of data.
Think that the permissions for read/modify files for a browser (its that you use in android for execute your game) are very dangerous, this is why xml doesnt work.