Android：保存 int 列表的最有效方法

Question

I'm trying to create a system to save the list of levels that have already been played in my application.

I've been using Editor and SharedPreferences to store information on the phone.

But now I have a list of int to save

I've been trying to figure out something with

 DataOutputStream out;

        //Size
        int resultSize = results.size();
        out.writeInt(resultSize);

        //All the levels ID
        for (int idx = 0; idx < resultSize; idx++){
            //l().debug("Lvl ID: "+results.get(idx));
            out.writeInt(results.get(idx));
        }

But then I don't know how to store this in the shared preferences.

I'm also concerned about size, this list of ID might get really big so I want to optimize the amount stored.(hence the DataStream)

any ideas

Jason

Answer 1

You could iterate through your list and construct a comma delimitted String from the ints. Eg "1,2,15..etc", then just write this string to SharedPreferences. You would obviously have to tokenize it when you read it back.

Answer 2

How big is "really big" exactly? Considering it's a list of levels played by a human I am going to assert that it is "small" for what a smartphone can handle. Though, personally I would recommend this to go in a SQLite table of "completed" levels for ease of querying the information.

Answer 3

I don't think that you need the most efficient way. This data is small, go with what you know. Pick something simple and understandable, something easy to debug.

A flat file with every level int on a new line. You can't get much simpler than that. Sure, it's bigger than the most efficient way, but it's much easier to recover from corrupted files, much easier to debug.

Answer 4

Binary stream is the most efficient way how to save integers. If you have really a lot of numbers (megabytes), use DataOutputStream combined with ZipOutputStream.