How to save rects from a for loop

Question

I've divide my screen up into rects, but I'm using a a for loop so I'm not storing the rects there getting remade each time. How would I store them in like an array?

     public void drawGrid() {
    //android.os.Debug.waitForDebugger();
    int height,width;
    int column,row;
    int maxColumn,maxRow;
    maxColumn = 4;
    maxRow = 4;
    column = 0;
    row = 0;
    height = c.getHeight()/maxRow;
    width = c.getWidth()/maxColumn;
    Paint pg = new Paint();
    Rect[] test[];


    for(int i = 0;i < 5; i++) {
        int srcX = column * width;
        int srcY = row * height;
        Rect src =new Rect(srcX,srcY,srcX + width, srcY +height);
        pg.setColor(Color.WHITE);
        pg.setStyle(Paint.Style.STROKE);
        pg.setStrokeWidth(5);
        c.drawRect(src, pg);
        if (column == maxColumn && row == maxRow){
            i = 5;
        } else {i=0;}
        if (column == maxColumn){
            row = row + 1;
            column = 0;
        } else {column = column + 1;}

    }



}

Answer 1

Allocate them in advance, so that you're not instantiating objects during a drawing operation. So whenever you determine the number of rects that you'll need (i.e. if it's always the same, initialize them in the constructor). Something like this:

Rect[] rects = new Rect[rectCount];
for(int i = 0; i < rectCount; i++) rects[i] = new Rect();

Then, in your drawing loop, use:

rects[i].set(srcX, srcY, srcX + width, srcY + height);

You should avoid allocating objects during a draw operation whenever possible.

EDIT: For a 2D array:

Rect[][] rects = new Rect[rowCount][colCount];
for(int i = 0; i < rowCount; i++) {
    for(int j = 0; j < colCount; j++) {
        rects[i][j] = new Rect();
    }
}

Then in the loop, it's the same thing:

rects[row][col].set(srcX, srcY, srcX + width, srcY + height);