Add variables to Arraylist and it replaces all previous elements , while variables are not static

Question

My question is similar to this one Add elements to Arraylist and it replaces all previous elements in Java . Though my variables are not static. Still everytime I add one, the o

Answer 1

tempPIX is reference to an int[] array in memory.

Each time you update the array and add it to the list, you are simply adding the same reference to the same array over and over again.

A better solution would be to create a new array on each loop...

int[] tmpAry = new int[2];
tmpAry[0] = ntempPIX[0] + tempDIR[0];
tmpAry[1] = tempPIX[1] + tempDIR[1];

tempPIX = tmpAry; // Reassign the reference so the rest of the code doesn't need to be updated

UPDATED from comments

Well, all I can say is, I don't know what you're doing...

public class TestArrays {

    public static void main(String[] args) {
        List listOfValues = new ArrayList();
        int[] outter = new int[] {1, 2, 3, 4};

        listOfValues.add(outter);
        dump(outter);
        for (int index = 0; index < 5; index++) {            
            int[] inner = new int[] {
                rand(),
                rand(),
                rand(),
                rand()
            };
            outter = inner;
            dump(outter);
            listOfValues.add(outter);            
        }

        int index = 0;
        for (int[] values : listOfValues) {
            System.out.print("[" + index + "] ");
            dump(values);
            index++;
        }

    }

    public static void dump(int[] values) {
        for (int value : values) {
            System.out.print(value + ", ");
        }
        System.out.println("\b\b"); // Cheeck...;)
    }

    public static int rand() {
        return (int)Math.round(Math.random() * 100);
    }

}

Which outputs something like...

1, 2, 3, 4
44, 35, 76, 9
44, 11, 17, 35
99, 24, 39, 23
20, 31, 9, 66
45, 50, 60, 27
[0] 1, 2, 3, 4
[1] 44, 35, 76, 9
[2] 44, 11, 17, 35
[3] 99, 24, 39, 23
[4] 20, 31, 9, 66
[5] 45, 50, 60, 27