How to Achieve Staggered Object Movement in Java: Utilizing Timers and Delays for a Fruit Ninja Effect?

Moving Objects and Timers

In this context, you want objects to randomly appear from the bottom of the screen, ascend to a certain height, and then descend back down in a manner similar to the game Fruit Ninja. However, you encounter an issue where all the objects begin at the same time due to the lack of staggered delays.

Solution:

To overcome this problem, you can introduce delays specific to each object. Below is an explanation of a possible approach using a Shape class with an ActionListener performing the movement based on a decreasing delay counter.

1. Shape Class with Delay and Movement Logic:

<code class="java">class Shape {

    private int randomDelayedStart;
    private boolean draw = false;
    private boolean down = false;
    private int y = D_HEIGHT; // Initial position at the bottom of the screen

    public void decreaseDelay() {
        if (randomDelayedStart <= 0) {
            draw = true;
        } else {
            randomDelayedStart -= 1;
        }
    }

    public void move() {
        if (draw) {
            if (y <= 50) {
                down = true;
            }

            if (down) {
                y += INCREMENT;
            } else {
                y -= INCREMENT;
            }
        }
    }
}</code>

2. Random Initialization for Each Shape:

When creating each Shape object, you can randomly assign a delay value:

<code class="java">for (int i = 0; i < 20; i++) {
    int randXLoc = random.nextInt(D_WIDTH);
    int randomDelayedStart = random.nextInt(100);
    Shape shape = new Shape(randXLoc, randomDelayedStart);
    list.add(shape);
}</code>

3. ActionListener to Trigger Shape Movement:

In a single Timer, an ActionListener can iterate through all shapes, decrement their delay counters, and invoke their movement methods:

<code class="java">ActionListener taskPerformer = new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        for (Shape s : shapes) {
            s.decreaseDelay();
            s.move();
            repaint();
        }
    }
};</code>

4. Starting the Timer:

After initializing all shapes, start the timer to initiate the continuous movement:

<code class="java">timer.start();</code>

This approach allows for independent delays and movement for each shape, ensuring that they appear and move in a staggered manner, resembling the desired behavior in Fruit Ninja.

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