flutter - 如何在 Dart 2 中限制 TextEditingController 侦听器事件 - Flutter
问题描述
我想知道是否有一些我可能错过的内置功能。我试图找到类似的东西,但是Dart 2 不再支持我找到的唯一包 ( throttle )
这是我想要节流的代码部分
final TextEditingController _filter = new TextEditingController();
String _searchText = "";
_filter.addListener(() {
if (_filter.text.isEmpty) {
setState(() {
_searchText = "";
});
} else {
setState(() {
_searchText = _filter.text;
});
}
//This action is being fired TOO many times :(
widget.onUpdateSearchTerm(_searchText);
});
有什么想法吗?
解决方案
我会使用throttle
或debounce
来自rxdart
在 rxdart 0.22.x 上使用Observable
final TextEditingController _filter = new TextEditingController();
String _searchText = "";
final _textUpdates = StreamController<String>();
_filter.addListener(() => _textUpdates.add(_filter.text));
Observable(_textUpdates.stream)
.throttle(const Duration(milliseconds: 700))
.forEach((s) {
if (s.isEmpty) {
setState(() {
_searchText = "";
});
} else {
setState(() {
_searchText = s;
});
}
//This action is being fired TOO many times :(
widget.onUpdateSearchTerm(_searchText);
});
在 rxdart 0.23.x 及更高版本上
final TextEditingController _filter = new TextEditingController();
String _searchText = "";
final _textUpdates = StreamController<String>();
_filter.addListener(() => _textUpdates.add(_filter.text));
_textUpdates.stream
.throttle(const Duration(milliseconds: 700))
.forEach((s) {
if (s.isEmpty) {
setState(() {
_searchText = "";
});
} else {
setState(() {
_searchText = s;
});
}
//This action is being fired TOO many times :(
widget.onUpdateSearchTerm(_searchText);
});
也可以看看