Java GUI Lesson 12 | Moving Graphics with arrow keys

teaching how to move a circle around with the arrow keys

[trueguide]

A 12 year old tutorial helped me out. Thanks!

[macheads]

If you don't care if the object continues going to the side, you don't need veld = 0. Furthermore, you set vely=-1.5 instead of 1.5 because the y coordinates are "flipped" in java and many other languages.

[MegaToasts]

i think it means it is void (doesn't have/is without) of a type, as opposed to it being a method of type "int" or "String", which would use "return" to display something its respective variable type

[sidelymations]

Just for people who are watching this now and want to make it so that *It only moves when you are holding the keys and stops when ur not*
make methods just like the up, down, left or right, but this time, make all the velX and velY doubles/integers(Depending on what you made it) as 0 and rename them to something like "up2" or "leftReleased" and add all these to the keyReleased method. heres a code of how I did it (you can add this into your class where you have the movement):


//the methods
public void (up2)
{
velX = 0;
velY = 0;
}
public void (down2)
{
velX = 0;
velY = 0;
}
public void (left2)
{
velX = 0;
velY = 0;
}
public void (right2)
{
velX = 0;
velY = 0;
}

//now add it in keyReleased
public void KeyReleased(KeyEvent e)
{
int key = e.getKeyCode();
if(key == ActionEvent.VK_UP)
{
up2();
}
if(key == ActionEvent.VK_DOWN)
{
down2();
}
if(key == ActionEvent.VK_LEFT)
{
left2();
}
if(key == ActionEvent.VK_RIGHT)
{
right2();
}
}

PS - This was so wierd to write this in youtube lol and sorry for my wierd style of code writing

[macheads]

@ComputerKing240 Just have an integer variable that you increment (add one to) every time the key event is fired.

[neocarbunkle]

Thank you! I spent the last hour trying to figure this out!

[jackyzou]

And heres a question, for example, you go up
public void up()
{
vely = -1.5;
velx = 0;
}
how comes the velocity of y equals to -1.5 directly, why not -=1.5?
And what's the reason to set velx = 0?

[macheads]

@scottyy888 If by application you mean class, you do not have to. Your main class could be a subclass of JFrame, but in general this is not good practice. Therefore, it's best to split your code up between multiple classes.

[macheads]

@malakov5 no i go over keeping it from going off screen in the previous tutorial

[فيافيالتأملمهمةإصلاح]

how to make it move in a non straight direction by using two buttons? 🤔

[elStusso]

Eclipse doesn't like the start() method for t. I don't know why, but I personally don't see a start() method it can refer to. It says "The method start() is undefined for the type Timer".

[macheads]

Remember to call .start(); you might not be using Swing timers. Try replacing "Timer" with "javax.swing.Timer".

[TehPiemaygor]

This is good, but I'm trying to make a square instead of a circle so what do I have to change? Oh, and is it possible to change the color of the shape as well?

[grandorottcod]

can you make a tutorial of how to do a 2D GAME LIKE A FROGGER WITH A GRID

[Scott]

I have a question, why did you need to have another application out for the JFrame and main method? you cant combine it all into one application?

[kanekiannx]

i was wondering if u can move it diagonally?

[jackyzou]

how comes mine doesn't move properly? Mine moves and fill the place that the shape moves to. It paints all over the place and all I want is to move the shape, not painting everywhere.

[Hwyadylaw]

Do you mean like a stop key or just make it stop when the arrow key(s) is released?

[LupuAlex]

what if I want to add 2 graphics to the same frame?

[AngelBeatz]

Hi I am facing a minor problem with this code, its like when I am done writing both the classes the class second has an error before it, and it says that some methods have not been implemented what should I do about that?