Android：在Android Studio中存储大型固定阵列

Question

I am trying to use a 2d array to do some mapping in android. Basically the task is to convert polar coordinates to cartesian coordinates(both coordinates have to be integers). This conversion is used to pick a value at the calculated X and Y coordinates.

I have an r and that input that needs to return x and y . (int)(R + rcostheta) and (int)(R - rsintheta) will give me the required values (since my original cartesian matrix is 2R * 2R ). But calculating them repeatedly is causing a lot of overhead. So i decided to pre-calculate the values of these so that i can avoid calculations. (And these calculations do take around 2-3 second overhead when I run my code)

ie, instead of using Value[x][y] , I can use

Value [ X[r][theta] ] [ Y[r][theta] ]

However this conversion matrix/2d array is pretty large. It has 128 x 960 elements (my applications has 128 radius and 960 segments). I keep getting a "code too large" error.

Can you suggest an easy way to implement this? ie, to store this mapping matrix somewhere where it can be referenced without too much overhead.

Some people suggest using a database. But since I am new to android programming it looks a little bit scary. Surely it can be done a lot simpler?

Currently I am storing my two mapping matrices as

int[][] X = new int[][]{
                 {229,230,231,232,233,234,235,236,237,238,239,240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,255,256,257,258,259,260,261,262,263,264,265,266,267,268,269,270,271,272,273,274,275,276,277,278,279,280,281,282,283,284,285,286,287,288,289,290,291,292,293,294,295,296,297,298,299,300,301,302,303,304,305,306,307,308,309,310,311,312,313,314,315,316,317,318,319,320,321,322,323,324,325,326,327,328,329,330,331,332,333,334,335,336,337,338,339,340,341,342,343,344,345,346,347,348,349,350,351,352,353,354,355,356},

{next line},
.
.
.
{last line};

And using it as

getBinary(tempBitmap, X[j][i],Y[j][i]);

This should work if the X and Y matrices were smaller. But since they are gigantic, I cant do it. Please suggest a way to go about doing this.

Answer 1

The computation doesn't look like it should take a long time - is it because you are you doing a large number of these calculations?

If a typical run of your application only uses a relatively small number of points, but does the conversion on them many times, then it would probably be best to do the calculation the first time that it's needed, and cache the result (in memory, if there isn't going to be a huge number of them).

If that's not going to work, then the next logical thing to do would indeed be to put the values into the database. This is a very common thing to do in an Android application, and there are a large number of tutorials available on the internet, in books, etc.