Using keyboard events
Handling keyboard events in normal web applications is not so common. However, if you are writing a web game, you'll almost certainly want to catch arrow key input, and the like. This recipe shows us how we can handle those events.
How to do it...
Look at the keyboard project. The web page is a copy of the page used in the Preventing an onSubmit event recipe, but now submit stays enabled. Suppose we also want to ensure that pressing the Enter key provokes submit, just like clicking on the submit button.
To that end, we add the following event listener to
main():document.onKeyPress.listen(_onKeyPress);
The
_onKeyPressmethod is as follows:_onKeyPress(KeyboardEvent e){ if (e.keyCode == KeyCode.ENTER) submit(e); }
Now, pressing Enter will cause the form to be submitted.
How it works...
The document object from dart:html has three events to work with key input: onKeyPress, onKeyDown, and onKeyUp. They all generate a stream of KeyboardEvent objects that capture user interaction...