Leaf Petersen
745f112ef6
Opt an initial batch of files under samples, samples-dev, utils, and runtime/tools/dartfuzz out of null safety in preparation for switching the flag on by default. Change-Id: Icdfd52a5a969e678a7205903332f73fe3841c223 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/166960 Reviewed-by: Daco Harkes <dacoharkes@google.com> Commit-Queue: Leaf Petersen <leafp@google.com>
48 lines
1.4 KiB
Dart
48 lines
1.4 KiB
Dart
// Copyright (c) 2011, the Dart project authors. Please see the AUTHORS file
|
|
// for details. All rights reserved. Use of this source code is governed by a
|
|
// BSD-style license that can be found in the LICENSE file.
|
|
|
|
// @dart = 2.9
|
|
|
|
|
|
part of touch;
|
|
|
|
/**
|
|
* Common events related helpers.
|
|
*/
|
|
class EventUtil {
|
|
/**
|
|
* Add an event listener to an element.
|
|
* The event callback is specified by [handler].
|
|
* If [capture] is true, the listener gets events on the capture phase.
|
|
* If [removeHandlerOnFocus] is true the handler is removed when there is any
|
|
* focus event, and added back on blur events.
|
|
*/
|
|
static void observe(
|
|
/*Element or Document*/ element, Stream stream, Function handler,
|
|
[bool removeHandlerOnFocus = false]) {
|
|
var subscription = stream.listen(handler);
|
|
// TODO(jacobr): this remove on focus behavior seems really ugly.
|
|
if (removeHandlerOnFocus) {
|
|
element.onFocus.listen((e) {
|
|
subscription.cancel();
|
|
});
|
|
element.onBlur.listen((e) {
|
|
subscription.cancel();
|
|
});
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Clear the keyboard focus of the currently focused element (if there is
|
|
* one). If there is no currently focused element then this function will do
|
|
* nothing. For most browsers this will cause the keyboard to be dismissed.
|
|
*/
|
|
static void blurFocusedElement() {
|
|
Element focusedEl = document.querySelector("*:focus");
|
|
if (focusedEl != null) {
|
|
focusedEl.blur();
|
|
}
|
|
}
|
|
}
|