How do I get perform a single button press to call a method? - unity3d

Question

I would like a Unity progress slider to fill up when I press the spacebar. Currently, I have to mash the spacebar 100 times to fill up the progress bar.
It fills the progress slider automatically when moved to update().
It fills the progress slider when I hold the spacebar if I change Input.GetKeyDown to Input.GetKey.
But I don't want to hold the spacebar down. I want to press it once to start have the slider value gradually fill up the progress bar.
void Start()
{
sliderValue = 1.0f;
}
void Update()
{
pressSpacebar();
}
void pressSpacebar()
{
if (Input.GetKeyDown("space"))
{
filluptheslider();
}
}
void filluptheslider()
{
ProgressSlider.value += sliderValue * Time.deltaTime;
}

Answer 1

There are a few ways to handle this:
Method 1
Boolean value in the class to track the pressed state:
bool pressed = false;
void pressSpacebar()
{
if (Input.GetKeyDown("space"))
{
filluptheslider();
}
if(pressed)
{
filluptheslider();
}
}
Method 2
Coroutine that starts after space is pressed.
void pressSpacebar()
{
if (Input.GetKeyDown("space"))
{
StartCoroutine(FillUpTheSlider);
}
}
IEnumerator FillUpTheSlider()
{
while(ProgressSlider.value < ProgressSlider.maxValue)
{
ProgressSlider.value += sliderValue * Time.deltaTime;
yield return null;
}
}
If you press the space bar multiple times, multiple coroutines will spawn and it will fill faster. You can optionally add the following before you start the coroutine to prevent this behaviour:
StopCoroutine(FillUpTheSlider)
You could alternatively combine method 1 and 2 to remove this behaviour.

Answer 2

bool isFull = false;
bool isPressed = false;
void Update
{
If (Input.GetKeyDown(KeyCode.Space)
&&
!isFull)
{
isPressed = true;
}
if(isPressed)
{
//if you want fill to increase every 0.05 seconds.
StartCoroutine(FillGradually(0.05f));
isPressed = false;
}
}
Ienumerator FillGradually(float fillOffset)
{
//If 100 is your max value
while(ProgressSlider.value < 100)
{
ProgressSlider.value += 1 * Time.deltaTime;
yield return new WaitForSeconds(fillOffset);
}
isFull = true;
}

Answer 3

You can just use a bool condition and when space is pressed, you can just make it true once and when it is true, it will automatically start filling.
bool isSpacePressed; //bydefault, bool class variable is set to false //when initialized
update()
{
if(isSpacePressed==true) //no need to mention ==true just added to make it //readable
{
image.fillAmount=fillvalue+0.1f;
}
}
if(input.GetKey(keyCode.Space)==true)
{
isSpacePressed=true;
}