How can I make it so that a specific sequence of button inputs would result in an action? For example, pressing p, then i, then e to make some pie appear.
programmar wrote ...
2012/2/21
Sequence of Button Inputs
You would need an instance String variable that is built as the keys are pressed; and compare it the whatever each possible word (or words) you expect the user to type out.
String builder = "";
public void act()
{
String key = Greenfoot.getKey();
if (key != null && key.length() == 1)
{
builder = builder + key;
if (builder.endsWith("pie"))
{
getWorld().addObject(new Pie(),
Greenfoot.getRandomNumber(getWorld().getWidth()),
Greenfoot.getRandomNumber(getWorld().getHeight()));
builder = ""; // once a string is found, we can clear builder
}
if (builder.endsWith( // etc.
// rest of act
}You might want to change line 8 to to make it case in-sensitive.
builder = builder + key.toLowerCase();
so I have
but it still doesn't work. What should I change?
private int speed = 7;
private int vSpeed = 1;
private int acceleration = 1;
String builder = "";
public void act()
{
checkKeys();
checkFall();
getattacked();
String key = Greenfoot.getKey();
if (key != null && key.length() == 1)
{
builder = builder + key.toLowerCase();
if (builder.endsWith("hot"))
{
setImage("pikachuduckpro.png");
builder = "";
}
}
} In line 18: setImage takes an image as the parameter (not a string); replace line 18 with
setImage(new GreenfootImage("pikachuduckpro.png"));
danpost, there is a setImage method accepting a String argument (as well as one accepting a GreenfootImage).
programmar: what do you mean by "it still doesn't work"? Can you be a bit more specific - are you getting a compiler error, or does it simply not do what you want?
davmac, there's no compiler error but it just doesn't do anything when the button sequence is pressed.
programmar, I am curious, what does checkKeys() look like? (it may not be working because of something there)
public class Pikachu extends Actor
{
/**
* Act - do whatever the Pikachu wants to do. This method is called whenever
* the 'Act' or 'Run' button gets pressed in the environment.
*/
private int speed = 7;
private int vSpeed = 1;
private int acceleration = 1;
String builder = "";
public void act()
{
checkKeys();
checkFall();
getattacked();
String key = Greenfoot.getKey();
if (key != null && key.length() == 1)
{
builder = builder + key.toLowerCase();
if (builder.endsWith("hot"))
{
setImage(new GreenfootImage("pikachuduckpro.png"));
builder = "";
}
}
}
private void checkKeys()
{
if (Greenfoot.isKeyDown("left") )
{
setImage("pikafightleftpro2.png");
moveLeft();
}
if (Greenfoot.isKeyDown("right") )
{
setImage("pikfightrightpro.png");
moveRight();
}
if (Greenfoot.isKeyDown("up") )
{ setImage("pikajumppro.png");
moveUp();
}
if (Greenfoot.isKeyDown("down") )
{
setImage("pikachuduckpro.png");
}
if ("shift".equals(Greenfoot.getKey()))
{
thunderbolt();
}
}
private void thunderbolt()
{
Thunderbolt thunderbolt = new Thunderbolt();
getWorld().addObject(thunderbolt, getX(), getY());
thunderbolt.setRotation(Greenfoot.getRandomNumber(360));
}
private void thunder()
{
Thunder thunder = new Thunder();
getWorld().addObject(thunder, getX(), getY() - 100);
}
public boolean onGround()
{
Actor under = getOneObjectAtOffset(0, 50, Ground.class);
return under != null;
}
public void checkFall()
{
if(onGround() )
vSpeed= 0;
else {
fall();
}
}
public void fall()
{
setLocation ( getX(), getY() + vSpeed);
vSpeed = vSpeed + acceleration;
}
public void moveRight()
{
setLocation ( getX() + speed, getY() );
}
public void moveLeft()
{
setLocation ( getX() - speed, getY() );
}
public void moveUp()
{
setLocation ( getX(), getY() - speed * 2);
}
private void getattacked()
{
Actor Ember;
Ember = getOneObjectAtOffset(0, 0, Ember.class);
if (Ember !=null)
{
bg1 world;
world = (bg1) getWorld();
world.removeObject(Ember);
Greenfoot.playSound("burn.wav");
world.bar.subtract(3);
}
Actor Ember2;
Ember2 = getOneObjectAtOffset(0, 0, Emberl.class);
if (Ember2 !=null)
{
bg1 world;
world = (bg1) getWorld();
world.removeObject(Ember2);
Greenfoot.playSound("burn.wav");
world.bar.subtract(3);
}
}
}yes, i use Greenfoot.getKey() more than once.
This is your problem. It returns the key that was pressed - whatever that is - the first time it's called; the second time it's called it will pretty much always return null.
See the documentation for the method:
Get the most recently pressed key, since the last time this method was called
Seeing as you call it twice, you would have to press a key exactly in between those two times that it is called in order for the second time to return something other than null - extremely unlikely!
In any case, I don't think that Greenfoot.getKey() can detect the shift key (it's an omission in the documentation) so your first call (line 50 in the code above) is useless. Use Greenfoot.isKeyDown() for that instead,An easy fix might be to move lines 18 through 28 and insert them at line 50 and change what was on line 50 to
most programmers will use the space bar to initiate firing an object.
if ("space".equals(key))It works now :) thanks again. By changing the firing method to if ("space".equals(key)) it fired multiple projectiles with one key press. I changed it to the code from http://www.greenfoot.org/topics/802.
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