我正在使用JavaFX和Scene Builder，我有一个带有文本字段的表单。其中三个文本字段从字符串解析为双精度浮点数。
我希望它们是学校成绩，因此只允许它们在1.0和6.0之间。用户不应该被允许写入像“2.34.4”这样的内容，但“5.5”或“2.9”之类的内容是可以的。
对解析字段进行验证：
public void validate(KeyEvent event) {
String content = event.getCharacter();
if ("123456.".contains(content)) {
// No numbers smaller than 1.0 or bigger than 6.0 - How?
} else {
event.consume();
}
}
如何测试用户输入的正确值？
我已经在Stackoverflow和Google上搜索过，但是没有找到一个令人满意的解决方案。
textField.focusedProperty().addListener((arg0, oldValue, newValue) -> {
if (!newValue) { //when focus lost
if(!textField.getText().matches("[1-5]\\.[0-9]|6\\.0")){
//when it not matches the pattern (1.0 - 6.0)
//set the textField empty
textField.setText("");
}
}
});
你也可以将模式更改为[1-5](\.[0-9]){0,1}|6(.0){0,1}，这样1,2,3,4,5,6都可以通过验证（不仅限于1.0,2.0,...）。
更新：下面是一个小的测试应用程序，允许值在1(.00)到6(.00)之间：
public class JavaFxSample extends Application {
@Override
public void start(Stage primaryStage) {
primaryStage.setTitle("Enter number and hit the button");
GridPane grid = new GridPane();
grid.setAlignment(Pos.CENTER);
Label label1To6 = new Label("1.0-6.0:");
grid.add(label1To6, 0, 1);
TextField textField1To6 = new TextField();
textField1To6.focusedProperty().addListener((arg0, oldValue, newValue) -> {
if (!newValue) { // when focus lost
if (!textField1To6.getText().matches("[1-5](\\.[0-9]{1,2}){0,1}|6(\\.0{1,2}){0,1}")) {
// when it not matches the pattern (1.0 - 6.0)
// set the textField empty
textField1To6.setText("");
}
}
});
grid.add(textField1To6, 1, 1);
grid.add(new Button("Hit me!"), 2, 1);
Scene scene = new Scene(grid, 300, 275);
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
我不建议你使用KeyEvent来实现这个功能。
你应该采用更传统的方式，比如在用户完成填写文本框或点击保存按钮时验证用户输入。
/**
* Called this when the user clicks on the save button or finish to fill the text field.
*/
private void handleSave() {
// If the inputs are valid we save the data
if(isInputValid()){
note=(DOUBLE.parseDouble(textField.getText()));
}else // do something such as notify the user and empty the field
}
/**
* Validates the user input in the text fields.
*
* @return true if the input is valid
*/
private boolean isInputValid() {
Boolean b= false;
if (!(textField.getText() == null || textFiled.getText().length() == 0)) {
try {
// Do all the validation you need here such as
Double d = Double.parseInt(textFiled.getText());
if ( 1.0<d<6.0){
b=true;
}
} catch (NumberFormatException e) {
}
return b;
}
final Pattern pattern = Pattern.compile("(6\\.0)|([1-5]\\.[0-9])");
textField.setTextFormatter(new TextFormatter<>(new DoubleStringConverter(), 0.0, change -> {
final Matcher matcher = pattern.matcher(change.getControlNewText());
return (matcher.matches() || matcher.hitEnd()) ? change : null;
}));
如果您可以使用第三方库：
类似的问题已经在这里得到了解答：表单验证器消息。
对于您的情况，您可以选择一个RegexValidator来检查文本字段输入，并传递您从之前的答案中得出的正则表达式：
JFXTextField validationField = new JFXTextField();
validationField.setPromptText("decimal between 1.0 and 6.0");
RegexValidator validator = new RegexValidator();
validator.setRegexPattern("[1-5](\\.[0-9]{1,2}){0,1}|6(\\.0{1,2}){0,1}");
validator.setMessage("Please enter proper value");
validationField.getValidators().add(validator);
validationField.focusedProperty().addListener((observable, oldValue, newValue) -> {
if(!newValue)
validationField.validate();
});
如果需要，您可以创建一个自定义的TextField来进行输入验证。
import java.awt.Toolkit;
import javafx.event.EventHandler;
import javafx.scene.control.TextField;
import javafx.scene.control.TextInputControl;
import javafx.scene.input.KeyEvent;
/**
* A text field that limits the user to certain number of characters and
* prevents the user from typing certain characters
*
*
*/
public class CustomTextField extends TextField
{
/**
* The maximum number of characters this text field will allow
* */
private int maxNumOfCharacters;
/**
* A regular expression of characters that this text field does not allow
* */
private String unallowedCharactersRegEx;
/*
* If no max number of characters is specified the default value is set
* */
private static final int DEFAULT_MAX_NUM_OF_CHARACTERS = 1000;
public CustomTextField()
{
maxNumOfCharacters = DEFAULT_MAX_NUM_OF_CHARACTERS;
this.setOnKeyTyped(new EventHandler<KeyEvent>() {
public void handle(KeyEvent event)
{
// get the typed character
String characterString = event.getCharacter();
char c = characterString.charAt(0);
// if it is a control character or it is undefined, ignore it
if (Character.isISOControl(c) || characterString.contentEquals(KeyEvent.CHAR_UNDEFINED))
return;
// get the text field/area that triggered this key event and its text
TextInputControl source = (TextInputControl) event.getSource();
String text = source.getText();
// If the text exceeds its max length or if a character that matches
// notAllowedCharactersRegEx is typed
if (text.length() > maxNumOfCharacters
|| (unallowedCharactersRegEx != null && characterString.matches(unallowedCharactersRegEx)))
{
// remove the last character
source.deletePreviousChar();
// make a beep sound effect
Toolkit.getDefaultToolkit().beep();
}
}
});
}
public int getMaxNumOfCharacters()
{
return maxNumOfCharacters;
}
public void setMaxNumOfCharacters(int maxNumOfCharacters)
{
this.maxNumOfCharacters = maxNumOfCharacters;
}
public String getUnallowedCharactersRegEx()
{
return unallowedCharactersRegEx;
}
public void setUnallowedCharactersRegEx(String notAllowedRegEx)
{
this.unallowedCharactersRegEx = notAllowedRegEx;
}
}
[1-5](\.[0-9]{1,2}){0,1}|6(.0{1,2}){0,1}。 - griFlo