Java, two dimensional array sort

Question

I'm quite new to Java, but getting into it. However, I can't wrap my head around why this example, which I found here, does not work:

At start of class:

String[][] spritesPaint = new String[20][20];

In method:

for (int funct1 = 0; funct1 <= 2; funct1++) {
    if (funct1 == 0) {
        for (int funct2 = 0; funct2 < rEnemyNumber; funct2++) {
            spritesPaint[0][funct2] = new Integer(rEnemyY[funct2])
                    .toString();
            spritesPaint[1][funct2] = rEnemyGraphic[funct2];
        }
    } else if (funct1 == 1) {
        Arrays.sort(Integer.valueOf(spritesPaint[0].toString()),
                new Comparator<Integer[]>() {
                    @Override
                    public int compare(final Integer[] entry1,
                            final Integer[] entry2) {
                        final Integer time1 = entry1[0];
                        final Integer time2 = entry2[0];
                        return time1.compareTo(time2);
                    }
                });

    } else if (funct1 == 2) {
        for (int funct3 = 0; funct3 < rEnemyNumber; funct3++) {
            if (rEnemyCheck[funct3] == true) {
                nextPaint = getImage(base, rEnemyGraphic[funct3]);
                System.out.println("Next: " + nextPaint);

                g.drawImage(nextPaint, rEnemyX[funct3] + worldCenterX,
                        rEnemyY[funct3] + worldCenterY, this);
            }
        }
    }
}

Basically, what I want to do is have a two dimensional array where I store Y position of object on the screen and an image path also related to that object, then sort it by the Y position integer. This should allow me to paint elements to the screen in the correct order for an isometric perspective.

However, I keep getting this error:

The method sort(T[], Comparator<? super T>) in the type Arrays 
is not applicable for the arguments (Integer, new Comparator<Integer[]>(){})

Please help me, I've been twisting my brain for hours trying to understand why I get this error now.

The first paramater of Arrays.sort() must be an array. You are passing an Integer. — jlordo
– jlordo, Commented Jan 16, 2013 at 20:18
@BevynQ: No, Arrays.sort() only takes an array as it's first parameter. — jlordo
– jlordo, Commented Jan 16, 2013 at 20:19

Alex DiCarlo · Accepted Answer · 2013-01-16 20:25:42Z

4

Integer.valueOf(spritesPaint[0].toString()) is a single integer, however from your description it seems that you want to sort the strings in the 1-dimensional array spritesPaint[0] as if they were integers. Here is a modification that will do just that:

Arrays.sort(spritesPaint[0], new Comparator<String>() {
    @Override public int compare(final String entry1, final String entry2) {
        final Integer time1 = Integer.valueOf(entry1);
        final Integer time2 = Integer.valueOf(entry2);
        return time1.compareTo(time2);
    }
});

Alternatively, if you are trying to sort the first dimension of the array by the first element of the second dimension of the array, modify as follows:

Arrays.sort(spritesPaint, new Comparator<String[]>() {
    @Override public int compare(final String[] entry1, final String[] entry2) {
        final Integer time1 = Integer.valueOf(entry1[0]);
        final Integer time2 = Integer.valueOf(entry2[0]);
        return time1.compareTo(time2);
    }
});

edited Jan 16, 2013 at 20:25

answered Jan 16, 2013 at 20:20

Alex DiCarlo

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2 Comments

Magnus Over a year ago

This made me go, "ahhh!" as to why it didn't run. And now it does run, except it does not really sort the Y values as I am hoping for. Currently there are four values, and they now output like this: Y: 450 Y: 600 Y: 550 Y: 500 ... could there be something else that I'm doing wrong?

Magnus Over a year ago

Ah, no, think I figured it out. My bad! :)

sdasdadas · Accepted Answer · 2013-01-16 20:20:03Z

3

The error message means that, instead of passing an Array of type T (generic), you are passing an Integer. So, where you have:

Arrays.sort(Integer.valueOf(spritesPaint[0].toString()), ...

you want to pass in

Arrays.sort(arrayToBeSorted, ...

(Also, your variables could do with better names because I really don't understand what this example is doing...)

answered Jan 16, 2013 at 20:20

sdasdadas

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