Flutter onPressed - Difference between using a function or make a direct call

Question

I am playing with Tapjoy's offerwall, I just don't know why this works:

ElevatedButton(
            child: Text("request content for Placement 001"),
            onPressed: myPlacement.requestContent,
          ),

And then this doesn't:

ElevatedButton(
            child: Text("request content for Placement 001"),
            onPressed: testFunction,
),

testFunction(){
    myPlacement.requestContent;
}

As you can see it's the same code but instead of calling directly I use a function...

requestContent returns a Future. This function internally makes a http request that I can see log in the console for the first option. The second one nothing happens..

Any ideas?

score 0 · Answer 1 · answered Jan 07 '22 at 20:00

0

ElevatedButton(
            child: Text("request content for Placement 001"),
            onPressed: testFunction(),
),

testFunction(){
    myPlacement.requestContent;
}

use bracket for the testFunction

answered Jan 07 '22 at 20:00

Yunus Kocatas

286
2
9

Yes! I was reading and found that is not the same to call a function with or without brackets. Without brackets you are not calling the funcion, you are referencing it. Am I right? – dxx Jan 07 '22 at 20:08
Actually, the trick was putting brackets inside de function: myPlacement.requestContent(); – dxx Jan 07 '22 at 20:11
did it worked for you – Yunus Kocatas Jan 07 '22 at 20:11

score 0 · Accepted Answer · answered Jan 08 '22 at 07:54

This block of code will work

ElevatedButton(
            child: Text("request content for Placement 001"),
            onPressed: testFunction, ),

testFunction(){
    myPlacement.requestContent(); 
}

Use the bracket after myPlacement.requestContent inside the testFunction().

Flutter onPressed - Difference between using a function or make a direct call

2 Answers2