What am I doing wrong?

Question about the task

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@Override
public void onKeyPress(Key key) {
    switch (key) {
        case LEFT:
            this.isRightPressed = false;
            this.isLeftPressed = true;
        case RIGHT:
            this.isLeftPressed = false;
            this.isRightPressed = true;
        case UP:
            this.isUpPressed = true;
    }
}

At this stage, we’ll implement the onKeyPress and onKeyReleased methods. As you can tell from the name, the onKeyPress method is called when any key is pressed, and the onKeyReleased method is called when a key is released. Let’s get started on the implementation of the onKeyPress method. It must process key presses for up, left, and right, and set the correct values for the corresponding flags (fields). Keep in mind that when the Left key is pressed, the isRightPressed flag must be set to false. An analogous condition holds true when the Right key is pressed. Also, when keys are released don’t forget to reset the corresponding flags in the onKeyReleased method.

Requirements:

The MoonLanderGame class must override the Game parent class's onKeyPress(Key) method.
The onKeyPress(Key) method must set the isUpPressed field to true if the method's parameter is equal to Key.UP.
If the onKeyPress(Key) method's parameter is Key.LEFT, the method must set the isLeftPressed field to true and the isRightPressed field to false.
If the onKeyPress(Key) method's parameter is Key.RIGHT, the method must set the isRightPressed field to true and the isLeftPressed field to false.
The MoonLanderGame class must override the Game parent class's onKeyReleased(Key) method.
The onKeyReleased(Key) method must set the isUpPressed field to false if the method's parameter is equal to Key.UP.
The onKeyReleased(Key) method must set the isLeftPressed field to false if the method's parameter is equal to Key.LEFT.
The onKeyReleased(Key) method must set the isRightPressed field to false if the method's parameter is equal to Key.RIGHT.

package com.codegym.games.moonlander; public class Rocket extends GameObject { private double speedY, boost; public Rocket(double x, double y) { super(x, y, ShapeMatrix.ROCKET); setSpeedY(0); setBoost(0.05); } public void move() { this.speedY += this.boost; this.y += this.speedY; } public double getSpeedY() { return this.speedY; } public void setSpeedY(double speedY) { this.speedY = speedY; } public double getBoost() { return this.boost; } public void setBoost(double boost) { this.boost = boost; } }

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Dyrits

Level 22

6 August 2020, 10:31

solution

I simplified it this way:

@Override
public void onKeyPress(Key key) {
    this.isRightPressed = key == Key.RIGHT;
    this.isLeftPressed = key == Key.LEFT;
    this.isUpPressed = key == Key.UP;
}

But the previous one should have been correct, I guess...

Samuel Schmid

Level 4 , Rothrist, Switzerland

6 August 2020, 10:50

solution

You were missing the break; statements in the switch cases. If you don't put a break; statement at the end of the case block, the code will just continue to execute the commands in the next case statement. For example:

public class Example {
    public static void main(String[] args) {
        int x = 4;

        switch (x) {
            case 3:
                System.out.println("it's 3");
            case 4:
                System.out.println("it's 4");
            case 5:
                System.out.println("it's 5");
        }
    }
}

This code will print out: it's 4 it's 5 because case 3 will not be entered (because x is 4), and then case 4 gets executed, but because of no break; it will also execute all the following cases. If you add breaks like so:

public class Example {
    public static void main(String[] args) {
        int x = 4;

        switch (x) {
            case 3:
                System.out.println("it's 3");
                break;
            case 4:
                System.out.println("it's 4");
                break;
            case 5:
                System.out.println("it's 5");
                break;
        }
    }
}

Then it will only print it's 4

Samuel Schmid

Level 4 , Rothrist, Switzerland

6 August 2020, 11:06

sorry, took me a while to figure out how to put code in comments, somehow the buttons were not showing up at the top ¯\_(ツ)_/¯

Dyrits

Level 22

6 August 2020, 18:15

Thank you. You're right. Stupid mistake.