Change button function dynamically

Programming Questions

blom_b

Change button function dynamically

in Programming Questions • 1 year ago

Hi there.

I'm having a row with a couple of buttons. It simulates physical buttons below a display. Above the buttons on the display there is a text saying what the buttons actions are.

Is there a nice way to change the button functions dynamically?

An example of what it could look like if the programming would allow it.

function currentFunc = rotateMap();
if (button1.klicked()){
callFunction(currentFunc);
}

Replies(6)

thomas.di..

Re: Change button function dynamically

1 year ago

if you are looking for something like function-pointers, you could use an interface.

void setup(){
MyMath functions[] = {
new Addition(),
new Subtraction(),
new Division(),
new Multiplication()
};
println( functions[0].run(4, 5)); // 4 + 5
println( functions[1].run(4, 5)); // 4 - 5
println( functions[2].run(4, 5)); // 4 / 5
println( functions[3].run(4, 5)); // 4 * 5
}
class Addition implements MyMath{
float run(float a, float b){
return a+b;
}
}
class Subtraction implements MyMath{
float run(float a, float b){
return a-b;
}
}
class Division implements MyMath{
float run(float a, float b){
return a/b;
}
}
class Multiplication implements MyMath{
float run(float a, float b){
return a*b;
}
}
interface MyMath{
float run(float a, float b);
}

hellochar

Re: Change button function dynamically

1 year ago

You're thinking in terms of "functional programming", which, unfortunately, processing (nor java) has. thomas' answer works great, but it's a bit verbose. If you're looking for a way to greatly expand your understanding of programming, dip your feet into FP.

PhiLho

Re: Change button function dynamically

1 year ago

Actually, that's the Java way to do a kind of "functional programming": we need, alas, to wrap all functions in a class.
In Java GUI, in general, we use anonymous classes and listeners, for this kind of programming.
Reusing the interface above, one can write:

button1.onClick(new MyMath() {
public float run(float a, float b) { return a * b; }
});

with onClick on the Button class defined as:

void onClick(MyMath function) {
mathFunction = function; // Set a field
}

and supposing Button has a mouseClicked method:

void mouseClicked () {
if (mathFunction != null) {
mathFunction.run(someA, someB);
}
}

quarks

Re: Change button function dynamically

1 year ago

You might like to try the GUI interface library G4P and its asscciated form designer - G4P GUI biuilder tool

In G4P each button can have its own user named function to handle events. For instance if you used the library to create a button called button1 then you can assign the event handler with

button1.addEventHandler(this, "rotate");

The function to be executed would be (The GButton parameter is required)

void rotate(GButton button) {
// code to execute
}

Then using
button1.addEventHandler(this, "translate");

and

void translate(GButton button) {
// code to execute
}

would reassign the function to be executed.

blom_b

Re: Change button function dynamically

1 year ago

quarks - That was just what I'm looking for.

The other solutions might work but that looked really simple.

But currently I'm using "guicomponents" for all buttons. That function might just make me switch.

Thank you guys for the answers!

quarks

Re: Change button function dynamically

1 year ago

But currently I'm using "guicomponents" for all buttons

guicomponents is the pakage name used by G4P so you probably already using this library.

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