Change Button scale on click - libgdx

Question

I want for all the Buttons in my game to scale down when user touch down the button and goes back to normal scale as soon as on touch up.What should be be the best possible way.Just like functionality of button in COCOS-2d.
I don't want to use extra small image for button down,if there is other alternative without using extra image.?
Second one is to produce some sound on click,I don't want to this in input listener of every button since sound is same for all buttons.How should i implement this in best possible way.
Thanks in advance.
// i just implement my custom class ,is there is other good way to implement.
public class ImprovedButton extends Button {
boolean isTouchDown=false;// is touch begin
float originalWidth,originalHeight; //actual size
#Override
public void draw(Batch batch, float parentAlpha) {
super.draw(batch, parentAlpha);
if( isPressed()) {
if (!isTouchDown) {
//play sound if any
isTouchDown=true;
originalHeight=getHeight();
originalWidth=getWidth();
setWidth(originalWidth*.95f);
setHeight(originalHeight*.95f);
}
}
else { //pressing is stopper if any
if (isTouchDown) {
isTouchDown=false;
setWidth(originalWidth);
setHeight(originalHeight);
}
}
}
}
one problem with this code is,pivot of scaling bottom left corner.How to set it as center.

Answer 1

I do the same thing on my games.
Make like your custom class for the button.
If you want you can increase the scale in the update method, so the button will scale smooth.
Look here, I wrote for you a example
public class CoolButton {
private Sprite sprite; // the sprite that we are going to use to draw our button
private float scale; // the scale of the button, 1 = full scale, 0.5 half, 2 = twice bigger, etc
public CoolButton(Texture texture, float x, float y, float width, float height) {
sprite = new Sprite(texture);
sprite.setPosition(x, y);
sprite.setSize(width, height);
sprite.setOriginCenter();
scale = 1;
}
public void draw(SpriteBatch batch) {
sprite.setScale(scale); // setting the scale and drawing the button
sprite.draw(batch);
}
// this method should be called when the user touches the screen (don't forget to unproject the coords)
public boolean touchDown(float x, float y) {
if (sprite.getBoundingRectangle().contains(x, y)) { // if the button is touched
scale = 0.7f;
return true;
}
return false;
}
// when you release the touch from the screen make the button back to its normal size
public void touchUp() {
scale = 1f;
}
}
If you have any question please comment here.

Answer 2

Here is a custom class ImprovedButton extends from Button class has additional functionality of Change in SCALE of button and plays SOUND on click .
There is also a class of ImprovedButtonStyle has paramter of scale and sound.
import com.badlogic.gdx.audio.Sound;
import com.badlogic.gdx.graphics.g2d.Batch;
import com.badlogic.gdx.scenes.scene2d.Actor;
import com.badlogic.gdx.scenes.scene2d.ui.Button;
import com.badlogic.gdx.scenes.scene2d.ui.Skin;
import com.badlogic.gdx.scenes.scene2d.utils.Drawable;
public class ImprovedButton extends Button {
boolean isPressedOnce=false;//is press started or touchDown
float originalWidth,originalHeight;
private ImprovedButtonStyle istyle;
public ImprovedButton() {
super();
this.istyle=new ImprovedButtonStyle();
}
public ImprovedButton(Actor child, ImprovedButtonStyle style) {
super(child, style);
this.istyle=style;
}
public ImprovedButton(Actor child, Skin skin, String styleName) {
this(child,skin.get(styleName, ImprovedButtonStyle.class));
}
public ImprovedButton(Actor child, Skin skin) {
this(child,skin.get(ImprovedButtonStyle.class));
}
public ImprovedButton(ImprovedButtonStyle style) {
super(style);
this.istyle=style;
}
public ImprovedButton(Drawable up, Drawable down, Drawable checked) {
super(up, down, checked);
istyle=new ImprovedButtonStyle();
}
public ImprovedButton(Drawable up, Drawable down) {
this(up, down,null);
}
public ImprovedButton(Drawable up) {
this(up,null,null);
}
public ImprovedButton(Skin skin, String styleName) {
super(skin, styleName);
this.istyle=skin.get(ImprovedButtonStyle.class);
}
public ImprovedButton(Skin skin) {
super(skin);
setStyle(skin.get(ButtonStyle.class));
}
#Override
public void draw(Batch batch, float parentAlpha) {
super.draw(batch, parentAlpha);
if( isPressed()) {
if (!isPressedOnce) {
if (istyle.sound!=null) {
istyle.sound.play();
}
isPressedOnce=true;
originalHeight=getHeight();
originalWidth=getWidth();
setWidth(originalWidth-istyle.changeInWidth);
setHeight(originalHeight-istyle.changeInHeight);
}
}
else {
if (isPressedOnce) {
isPressedOnce=false;
setWidth(originalWidth);
setHeight(originalHeight);
}
}
}
#Override
protected void drawBackground(Batch batch, float parentAlpha, float x,float y) {
int offsetX=0;
int offsetY=0;
if(isPressed()){
offsetX=istyle.changeInWidth/2;
offsetY=istyle.changeInHeight/2;
}
super.drawBackground(batch, parentAlpha, x+offsetX, y+offsetY);
}
public static class ImprovedButtonStyle extends ButtonStyle{
public int changeInWidth=2,changeInHeight=2;
public Sound sound=null;
public ImprovedButtonStyle() {
super();
}
public ImprovedButtonStyle(ButtonStyle style,int changeInWidth,int changeInHeight,Sound sound) {
super(style);
this.changeInHeight=changeInHeight;
this.changeInWidth=changeInWidth;
this.sound=sound;
}
public ImprovedButtonStyle(Drawable up, Drawable down, Drawable checked) {
super(up, down, checked);
}
public ImprovedButtonStyle(ImprovedButtonStyle style) {
super(style);
this.changeInHeight=style.changeInHeight;
this.changeInWidth=style.changeInWidth;
this.sound=style.sound;
}
}
}