I'd like to execute a function after a certain delay after my Widget is built. What's the idiomatic way of doing this in Flutter?
What I'm trying to achieve:
I'd like to start with a default FlutterLogo
Widget and then change its style
property after some duration.
This question is related to
flutter
import 'dart:async';
Timer timer;
void autoPress(){
timer = new Timer(const Duration(seconds:2),(){
print("This line will print after two seconds");
});
}
autoPress();
Just adding more description over the above answers
The Timer functionality works with below duration time also:
const Duration(
{int days = 0,
int hours = 0,
int minutes = 0,
int seconds = 0,
int milliseconds = 0,
int microseconds = 0})
Example:
Timer(Duration(seconds: 3), () {
print("print after every 3 seconds");
});
You can do it in two ways 1 is Future.delayed
and 2 is Timer
Using Timer
Timer
is a class that represents a count-down timer that is configured to trigger an action once end of time is reached, and it can fire once or repeatedly.
Make sure to import dart:async
package to start of program to use Timer
Timer(Duration(seconds: 5), () {
print(" This line is execute after 5 seconds");
});
Using Future.delayed
Future.delayed
is creates a future that runs its computation after a delay.
Make sure to import "dart:async";
package to start of program to use Future.delayed
Future.delayed(Duration(seconds: 5), () {
print(" This line is execute after 5 seconds");
});
Just leaving here the snippet everyone is looking for:
Future.delayed(Duration(milliseconds: 100), () {
// Do something
});
Future.delayed(Duration(seconds: 3) , your_function)
(Adding response on old q as this is the top result on google)
I tried yielding a new state in the callback within a bloc, and it didn't work. Tried with Timer and Future.delayed.
However, what did work was...
await Future.delayed(const Duration(milliseconds: 500));
yield newState;
Awaiting an empty future then running the function afterwards.
You can use Future.delayed
to run your code after some time. e.g.:
Future.delayed(const Duration(milliseconds: 500), () {
// Here you can write your code
setState(() {
// Here you can write your code for open new view
});
});
In setState function, you can write a code which is related to app UI e.g. refresh screen data, change label text, etc.
await Future.delayed(Duration(milliseconds: 1000));
Trigger actions after countdown
Timer(Duration(seconds: 3), () {
print("Yeah, this line is printed after 3 seconds");
});
Repeat actions
Timer.periodic(Duration(seconds: 5), (timer) {
print(DateTime.now());
});
Trigger timer immediately
Timer(Duration(seconds: 0), () {
print("Yeah, this line is printed immediately");
});
Source: Stackoverflow.com