Waiting for a user input.

Programming Questions

quid.pro...

in Programming Questions • 3 years ago

How can I go about waiting for a user input...I would like to stop execution of the program until an acceptable condition occurs (if the acceptable condition does not occur repeat the function until it is acceptable).

Basically, I would like a do-while loop and pause until the key 'y' is pressed (to accept the value) or 'n' is pressed, to repeat the do-while loop.

Replies(3)

PhiLho

Re: Waiting for a user input.

3 years ago

Use noLoop().

quid.pro...

Re: Waiting for a user input.

3 years ago

Thanks for the suggestion. I don't think that is quite what I'm looking for, but perhaps there is a way to implement it that I haven't tried.

Here's an example to illustrate the problem:

void setup() {
size(200,200);
}
void draw() {
println("The number you chose was: " + numberPicker()); //number chosen takes place in numberPicker
}
int numberPicker() {
int tempNumber; //the number to be replaced if unacceptable
boolean retry = true; //variable that controls if a new number is to be displayed
do {
tempNumber = int(random(0,10));
println("Would you like to keep " + tempNumber + "? y/n");
while(keyPressed == false); //Do nothing until a key is pressed
if(key == 'y')
{
retry = false;
}
}
while(retry == true);
return tempNumber;
}

What I think is happening is println() will not display which number is randomly selected until it goes through draw(). I cannot call redraw() because " it only sets a flag that indicates an update is needed" Therefore it will not display the random number for selection because I have stuck it in a while loop.

Another issue is using the while loop itself, " It will lock out all other code from running (mouse events will not be updated, etc.)" So by doing it this way it will not register a 'y' key being pressed.

Suggestions on a work-around would be greatly appreciated. :)

blindfish

Re: Waiting for a user input.

3 years ago

I don't particularly like recommending noLoop() as it generally tends to cause problems further down the line, but it's certainly a valid solution in this case:

int tempNumber;
boolean picked = false;
void setup() {
}
void draw() {
if(!picked) {
tempNumber = int(random(0,10));
println("Would you like to keep " + tempNumber + "? y/n");
noLoop();
}
else {
println("you picked " + tempNumber);
noLoop();
}
}
void keyPressed() {
if(key == 'n'){
loop();
}
else if(key == 'y') {
picked = true;
loop();
}
}

However if you want things to continue in the background you'll do better to use a variable to determine the state of the system...

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