Flutter 14 - Async programming

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[cutechamps]

You way to explain code and giving example for every different scenario is very good. It help us understand the concepts in deep. Big thanx to you. Loved It.

[stuff]

Great video! One thing to point out, Dart is single threaded (if not running on multiple isolates) meaning no code is ever parallel. Async or futures run in a eventloop, and async tasks can be queued very efficiently. This means more preformance (ie more work per sec) when theres is waiting that needs to be done (database, http, etc) by the CPU. But async wont help if you are blocking ie. calculating something expensive like large primes.

[mertmertoglu]

I couldn't figure out why the following code didn't work correctly. >> 5:27 <<

I dont get it, Its the same code.
I also tried it on DartPad. The result is the same.

my result and DartPad's result:
starting
Async 0
Async 1
Async 2
Async 3
Async 4
done

According to video, it has to be:
starting
done
Async 0
Async 1
Async 2
Async 3
Async 4

The Code:

import 'dart:async';

Future<bool> longWait(String prefix) async {
for (int i = 0; i < 5; i++) {
print('$prefix $i');
}
return true;
}

Future testAsync() async {
print('starting');
longWait('Async');
print('done');
}

main() {
testAsync();
}

[rogeriolimas]

Spectacular, my friend!
Quoting Elvis: "Thank you very much!" 😜

[shadowmn]

FYI, your testChain() code appears to have been broken in the transition from Dart 1 to Dart 2. The fix is to add an explicit type parameter to the function assignment on line 30. It should now read:
Future<bool> f = longWait('Chains');

I found the explanation & fix on the following page:

[pebre]

This was very helpful. thanks for posting!

[yeeppers]

Neat, extremely similar to ES async/await

[devopssimon]

Very much the same as Javascript promises except dart calls them futures.

[akhilsoman]

For me the output was same as it would be if it wasn't asynchronous. Without using "await" => Starting - Async - Done.. Even tried a higher number in the for loop condition. Why the difference..? Is anything changed since then..?

[JoaoCSpeixoto]

the examples won't work anymore in current dart/flutter version.

[KingHerring]

this is cool but I don't like Dart!! we want more QML vids!! >:)