英文:
How i can get the end event in javafx TextField
问题
我有一个文本字段，通过扫描仪读取的条形码会传递一个数字，但我不知道条形码有多少位数字，所以我想知道事件何时完成，以获取完整的扫描数字。
以下是代码：
txSerialId.textProperty().addListener((obs, oldText, newText) -> {
System.out.println("addListener..........obs : " + obs);
System.out.println("addListener..........oldText: " + oldText);
System.out.println("addListener..........newText: " + newText);
});
我正在使用JavaFx 8。
英文:
I have a text field that receives a number read from barcode by scanner, but i don't know how many digits the barcode has, so, I would like to know when the event was finished, for get the complete number scanned.
Here is the code
txSerialId.textProperty().addListener((obs, oldText, newText) -> {
System.out.println("addListener..........obs : " + obs);
System.out.println("addListener..........oldText: " + oldText);
System.out.println("addListener..........newText: " + newText);
});
I am using JavaFx 8.
答案1
得分: 1
以下是翻译好的内容：
目前我所知，没有特别好的方法来处理这个，因为在将其读入文本字段时，没有任何指示“扫描结束”的内容（除非您提前知道条形码文本的长度）。
我能提出的最佳建议是等待一段时间内没有输入更改。这应该有效，因为文本将被扫描仪快速读取；但这会导致在响应扫描时有轻微延迟。
您可以使用`PauseTransition`来实现这一点，并在暂停完成时更新`StringProperty`：
final PauseTransition scannerDelay = new PauseTransition(Duration.seconds(0.25));
final StringProperty barcode = new SimpleStringProperty();
// 当延迟完成时，使用文本字段中的文本更新条形码：
scannerDelay.setOnFinished(event -> barcode.set(txSerialId.getText()));
// 当文本字段中的文本更改时，启动（或重新启动）延迟：
txSerialId.textProperty().addListener((obs, oldText, newText) ->
scannerDelay.playFromStart());
// 响应条形码更改：
barcode.addListener((obs, oldBarcode, newBarcode) ->
System.out.printf("条形码从%s更改为%s %n", oldBarcode, newBarcode));
英文:
There's no particularly nice way to do this, as far as I know, because there's nothing that indicates the "end of scan" when reading this into a text field (unless you know ahead of time the length of the barcode text).
The best I can suggest is to wait until no changes have been input for some short period of time. This should work, because the text will be read by the scanner rapidly; it comes at the cost of a slight delay in reacting to the scan.
You can do this using a PauseTransition, and update a StringProperty when the pause completes:
final PauseTransition scannerDelay = new PauseTransition(Duration.seconds(0.25));
final StringProperty barcode = new SimpleStringProperty();
// when delay finishes, update barcode with text in text field:
scannerDelay.setOnFinished(event -> barcode.set(txSerialId.getText());
// when text in text field changes, start (or restart) the pause:
txSerialId.textProperty().addListener((obs, oldText, newText) ->
scannerDelay.playFromStart());
// react to changes in barcode:
barcode.addListener((obs, oldBarcode, newBarcode) ->
System.out.printf("Barcode changed from %s to %s %n", oldBarcode, newBarcode));
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