12.04 অ্যাসিংক্রোনাস প্রোগ্রামিং উদাহরন

Future fetchUserData() async {
print("1. Start fetching user data...");

String userData = await simulateNetworkRequest();
print("2. User data fetched: $userData");

print("3. Fetching additional user details...");
simulateAdditionalRequest().then((value) {
  print("4. Additional user details fetched: $value");
});

print("5. End fetching user data.");
}

Future simulateNetworkRequest() async {
print("6. Simulating network request...");
await Future.delayed(Duration(seconds: 2)); // Simulate a network delay
return "User data";
}

Future simulateAdditionalRequest() async {
print("7. Simulating additional request...");
await Future.delayed(Duration(seconds: 1)); // Simulate a delay
return "Additional details";
}

void main() {
print("Main function starts.");

fetchUserData().then((_) {
  print("8. Async operation completed.");
});

print("Main function continues executing...");

// Let's add a delay to ensure the program doesn't exit immediately
Future.delayed(Duration(seconds: 4), () {
  print("9. Main function ends.");
});
}
 

Main function starts.

1. Start fetching user data...
6. Simulating network request...
Main function continues executing...
2. User data fetched: User data
3. Fetching additional user details...
7. Simulating additional request...
5. End fetching user data.
8. Async operation completed.
4. Additional user details fetched: Additional details
9. Main function ends.