Question

I’ve been experiencing occasional lags in my Android game when the garbage collector runs. I ran DDMS and discovered that all of the memory being allocated by my application is from this line:

scoreString = String.valueOf(score);

What is the best way to convert an integer to a string without allocating any memory?

Answer 1

Allocate an array of characters to be displayed as the score, and use a lookup table of 0-9 (this conveniently maps to a 0-base array anyway) to append to this array based on each digit of the score.

Edit:
To extract the digits from your score:

12345 mod 10 = 5
12345 mod 100 = 45 / 10 = 4.5 (floors to 4)
12345 mod 1000 = 345 / 100 = 3.45 (floors to 3)
12345 mod 10000 = 2345 / 1000 = 2.345 (floors to 2)
12345 mod 100000 = 12345 / 10000 = 1.2345 (floors to 1)

Also you’ll know what the max length for the score character array should be based on whatever you’re using to store score (i.e. int)

I recommend reverse-filling this array and initializing it to all ‘0’ so your score will display like

0000000000
0000005127