带有 TextFormatter 和/或 UnaryOperator 的 JavaFX 8 中整数的数字文本字段

Numeric TextField for Integers in JavaFX 8 with TextFormatter and/or UnaryOperator

提问by ShadowEagle

I am trying to create a numeric TextField for Integers by using the TextFormatter of JavaFX 8.

我正在尝试使用 JavaFX 8 的 TextFormatter 为整数创建数字 TextField。

Solution with UnaryOperator:

使用 UnaryOperator 的解决方案：

UnaryOperator<Change> integerFilter = change -> {
    String input = change.getText();
    if (input.matches("[0-9]*")) { 
        return change;
    }
    return null;
};

myNumericField.setTextFormatter(new TextFormatter<String>(integerFilter));

Solution with IntegerStringConverter:

IntegerStringConverter 的解决方案：

myNumericField.setTextFormatter(new TextFormatter<>(new IntegerStringConverter()));  

Both solutions have their own problems. With the UnaryOperator, I can only enter digits from 0 to 9 like intended, but I also need to enter negative values like "-512", where the sign is only allowed at the first position. Also I don't want numbers like "00016" which is still possible.

这两种解决方案都有自己的问题。使用 UnaryOperator，我只能像预期的那样输入 0 到 9 的数字，但我还需要输入负值，例如“-512”，其中符号只允许在第一个位置。另外我不想要像“00016”这样的数字，这仍然是可能的。

The IntegerStringConverter method works way better: Every invalid number like "-16-123" is not accepted and numbers like "0123" get converted to "123". But the conversion only happens when the text is commited (via pressing enter) or when the TextField loses its focus.

IntegerStringConverter 方法的效果更好：不接受像“-16-123”这样的每个无效数字，并且像“0123”这样的数字被转换为“123”。但转换仅在提交文本（通过按 Enter 键）或 TextField 失去焦点时发生。

Is there a way to enforce the conversion of the second method with the IntegerStringConverter every time the value of the TextField is updated?

有没有办法在每次更新 TextField 的值时使用 IntegerStringConverter 强制执行第二种方法的转换？

采纳答案by James_D

The converter is different to the filter: the converter specifies how to convert the text to a value, and the filter filters changes the user may make. It sounds like here you want both, but you want the filter to more accurately filter the changes that are allowed.

转换器与过滤器不同：转换器指定如何将文本转换为值，而过滤器过滤器可能会更改用户。听起来在这里你想要两者，但你希望过滤器更准确地过滤允许的更改。

I usually find it easiest to check the new value of the text if the change were accepted. You want to optionally have a -, followed by 1-9with any number of digits after it. It's important to allow an empty string, else the user won't be able to delete everything.

如果更改被接受，我通常发现检查文本的新值最容易。您希望有一个-, 后跟1-9任意数量的数字。允许空字符串很重要，否则用户将无法删除所有内容。

So you probably need something like

所以你可能需要类似的东西

UnaryOperator<Change> integerFilter = change -> {
    String newText = change.getControlNewText();
    if (newText.matches("-?([1-9][0-9]*)?")) { 
        return change;
    }
    return null;
};

myNumericField.setTextFormatter(
    new TextFormatter<Integer>(new IntegerStringConverter(), 0, integerFilter));

You can even add more functionality to the filter to let it process -in a smarter way, e.g.

您甚至可以向过滤器添加更多功能，让它-以更智能的方式处理，例如

UnaryOperator<Change> integerFilter = change -> {
    String newText = change.getControlNewText();
    // if proposed change results in a valid value, return change as-is:
    if (newText.matches("-?([1-9][0-9]*)?")) { 
        return change;
    } else if ("-".equals(change.getText()) ) {

        // if user types or pastes a "-" in middle of current text,
        // toggle sign of value:

        if (change.getControlText().startsWith("-")) {
            // if we currently start with a "-", remove first character:
            change.setText("");
            change.setRange(0, 1);
            // since we're deleting a character instead of adding one,
            // the caret position needs to move back one, instead of 
            // moving forward one, so we modify the proposed change to
            // move the caret two places earlier than the proposed change:
            change.setCaretPosition(change.getCaretPosition()-2);
            change.setAnchor(change.getAnchor()-2);
        } else {
            // otherwise just insert at the beginning of the text:
            change.setRange(0, 0);
        }
        return change ;
    }
    // invalid change, veto it by returning null:
    return null;
};

This will let the user press -at any point and it will toggle the sign of the integer.

这将让用户-在任何点按下，它会切换整数的符号。

SSCCE:

SSCCE：

import java.util.function.UnaryOperator;

import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TextField;
import javafx.scene.control.TextFormatter;
import javafx.scene.control.TextFormatter.Change;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import javafx.util.StringConverter;
import javafx.util.converter.IntegerStringConverter;

public class IntegerFieldExample extends Application {

    @Override
    public void start(Stage primaryStage) {
        TextField integerField = new TextField();
        UnaryOperator<Change> integerFilter = change -> {
            String newText = change.getControlNewText();
            if (newText.matches("-?([1-9][0-9]*)?")) { 
                return change;
            } else if ("-".equals(change.getText()) ) {
                if (change.getControlText().startsWith("-")) {
                    change.setText("");
                    change.setRange(0, 1);
                    change.setCaretPosition(change.getCaretPosition()-2);
                    change.setAnchor(change.getAnchor()-2);
                    return change ;
                } else {
                    change.setRange(0, 0);
                    return change ;
                }
            }
            return null;
        };

        // modified version of standard converter that evaluates an empty string 
        // as zero instead of null:
        StringConverter<Integer> converter = new IntegerStringConverter() {
            @Override
            public Integer fromString(String s) {
                if (s.isEmpty()) return 0 ;
                return super.fromString(s);
            }
        };

        TextFormatter<Integer> textFormatter = 
                new TextFormatter<Integer>(converter, 0, integerFilter);
        integerField.setTextFormatter(textFormatter);

        // demo listener:
        textFormatter.valueProperty().addListener((obs, oldValue, newValue) -> System.out.println(newValue));

        VBox root = new VBox(5, integerField, new Button("Click Me"));
        root.setAlignment(Pos.CENTER);
        Scene scene = new Scene(root, 300, 120);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}

回答by user8498734

 TextField txtpoint = new TextField();
    txtpoint.textProperty().addListener(new ChangeListener<String>() {
        @Override
        public void changed(ObservableValue<? extends String> observable, String oldValue, String newValue) {
            if (!newValue.isEmpty()) {
                try {
                    long pointI = Integer.parseInt(newValue);
                    txtpoint.setText(String.valueOf(pointI));
                } catch (Exception e) {
                    txtpoint.clear();
                    txtpoint.setText(getNumber(oldValue));
                }
            }
        }
    });


private String getNumber(String value) {
    String n = "";
    try {
        return String.valueOf(Integer.parseInt(value));
    } catch (Exception e) {
        String[] array = value.split("");
        for (String tab : array) {
            try {
                System.out.println(tab);
                n = n.concat(String.valueOf(Integer.parseInt(String.valueOf(tab))));
            } catch (Exception ex) {
                System.out.println("not nomber");
            }
        }
        return n;
    }
}