Why is drawString not updating values?

Question

I am drawing this (in the paint method):

g.drawString("NumPipes: " + numPipes + "   " + "DeletedPipes: " + deletedPipes + "    moved: " + numMoved, 0 , 10);

To output the values defined in these following methods:

public void addPipe() {
    for (int i = 0; i < pipe.length; i++) {
        if (pipe[i] == null) {
            pipe[i] = new Pipe(this.width, (int) Math.random() * (this.height - 200));
            System.out.println("Pipe Added.");
            numPipes += 1;
        }
    }
}

public void deletePipe() {
    for (int i = 0; i < pipe.length; i++) {
        if (pipe[i] != null && pipe[i].returnX() <= 0) {
            pipe[i] = null;
            System.out.println("Pipe Deleted.");
            deletedPipes += 1;
        }
    }
}

public void movePipe(int speed) {
    for (int i = 0; i < pipe.length; i++) {
        if (pipe[i] != null) {
            pipe[i].move(speed);
            numMoved = numMoved + 1;
            System.out.println(numMoved);
        }
    }
}

Now when I check the console for the outputted value of numMoved, the values are increasing/updating but they stay the same in the JFrame (See below image, the console displays the value of numMoved and the JFrame shows the drawString values). What is happening/Why is it doing this?

Answer 1

You don't seem to be calling repaint, so that component doesn't know that it should update the values...

For example...

public void addPipe() {
    for (int i = 0; i < pipe.length; i++) {
        if (pipe[i] == null) {
            pipe[i] = new Pipe(this.width, (int) Math.random() * (this.height - 200));
            System.out.println("Pipe Added.");
            numPipes += 1;
        }
    }
    repaint();
}

Now, you could place repaint after numPipes += 1, but because of the way repaint works, it probably won't make a difference...

This assumes that the class that addPipe belongs to is some kind of component, but you've not supplied enough information to make proper diagnoses...