Hot reload

Learn what hot reload does and why it is essential.

Hot reload

Hot reload updates the app within seconds when you edit and save code, without restarting it. State is preserved; form data, scroll position and counters do not disappear. It is the most used feature during development.

# while flutter run is active, press 'r'
$ flutter run
# For hot reload: r
# For hot restart: R

Hot restart and DevTools

Hot restart (with R), unlike hot reload, resets all state and restarts the app from scratch; the widget tree is re-instantiated. Flutter DevTools offers advanced debugging tools such as performance profiling, widget tree inspection and network request monitoring.

# flutter run interactive keys:
# r = hot reload (state preserved)
# R = hot restart (state reset)
# q = quit

# Open DevTools in the browser:
$ flutter pub global run devtools

Exercise Print reload info

In main, print two lines with print: reload state korur and restart state sifirlar.

Show example solution

void main() {
  print('reload state korur');
  print('restart state sifirlar');
}

Test yourself

What state does hot reload preserve?
- Buffer memory
- App state
- Build output
- Network packets
Show answer

App state — Hot reload preserves app state while applying changes; restart resets it.

Hot reload key

# hot reload: ____
# hot restart: R

Show answer

# hot reload: r
# hot restart: R

Hot reload and restart

Hot reload

Applies changes while preserving state
Hot restart

Resets state and restarts
r tuşu

Triggers hot reload
DevTools

Profiling and debugging tools

Next lesson: Summary - First app

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