如何在 Javafx 和 Scene Builder 中使用一个事件处理程序方法管理多个按钮

Question

我有 14 对按钮与两组文本字段相关联，它们将相关联的文本字段递增和递减 2。每个文本字段显示有多少对特定重量的盘子要加载到杠铃上。它们存储在两个二维数组中，一个用于磅，另一个用于千克。 [递增或递减][按钮]

final Button[][] poundIncrementDecrementButton = new Button[2][7];
final Button[][] kilogramIncrementDecrementButton = new Button[2][7];

我正在使用 Scene Builder 和 JavaFX，我正在努力避免编写 28 个 @FXML 事件处理程序。到目前为止，这是我想出的遍历每个数组的方法，但我不确定如何替换 lambda 表达式来完成这项工作。

// assigns event handlers to increment and decrement buttons.
private void incrementDrecimentButtonEventHandlers() {

    // p=1 increment buttons, p=2 decrement buttons
    for (int p = 0; p < poundIncrementDecrementButton.length; p++) {
        // loops through buttons
        for (int j = 0; j < poundIncrementDecrementButton[p].length; j++) {
            Button incrementButton = poundIncrementDecrementButton[p][j];
            final int incrementDecriment = p;
            final int textField = j;
            incrementButton.setOnAction((ActionEvent event) -> {
                incrementDecrementPlate("pounds", incrementDecriment, textField);
            });
        }

        // k=1 increment buttons, k=2 decrement buttons
        for (int k = 0; k < kilogramIncrementDecrementButton.length; k++) {
            // loops through buttons
            for (int j = 0; j < kilogramIncrementDecrementButton[k].length; j++) {
                Button incrementButton = kilogramIncrementDecrementButton[k][j];
                final int incrementDecriment = k;
                final int textField = j;
                incrementButton.setOnAction((ActionEvent event) -> {
                    incrementDecrementPlate("kilograms", incrementDecriment, textField);
                });
            }

        }
    }
}

然后我让事件处理程序使用相关索引调用此方法。

// increments or decrements the plates
private void incrementDecrementPlate(String unit, int incrementDecrement, int textField) {

    Double oldValue = Double.parseDouble(poundTextFieldList.get(textField).getText());
    String incremented;
    String decremented;

    if (oldValue % 2 != 0) {
        incremented = Double.toString(oldValue + 1);
    } else {
        incremented = Double.toString(oldValue + 2);
    }

    if (oldValue % 2 != 0) {
        decremented = Double.toString(oldValue - 1);
    } else if (oldValue != 0) {
        decremented = Double.toString(oldValue - 2);
    } else {
        decremented = Double.toString(oldValue);
    }

    switch (unit) {
        case "pounds":
            if (incrementDecrement == 0) {
                poundTextFieldList.get(textField).setText(incremented);
            } else {
                poundTextFieldList.get(textField).setText(decremented);
            }
            break;
        case "kilograms":
            if (incrementDecrement == 0) {
                kilogramTextFieldList.get(textField).setText(incremented);
            } else {
                kilogramTextFieldList.get(textField).setText(decremented);
            }
            break;
    }
}

Answer 1

以下代码演示了如何让一组 (2) 个按钮递增文本字段的值：

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TextField;
import javafx.scene.layout.GridPane;
import javafx.stage.Stage;

public class FxMain extends Application {

    private Button[] increment, decrement;
    private TextField[] txt;
    private static final int numberOfGroups = 3;

    @Override
    public void start(Stage stage) {

        initComponents(numberOfGroups);
        GridPane root = new GridPane();
        for(int row =0; row < numberOfGroups; row++){ //add all components 
            root.addRow(row, decrement[row], txt[row],increment[row]);
        }
        Scene scene = new Scene(root);
        stage.setScene(scene);
        stage.show();
    }

    //create and initialize components 
    private void initComponents(int size) {
        increment = new Button[size]; decrement = new Button[size];
        txt = new TextField[size];

        for(int group = 0; group < size; group++) {
            final int i = group;
            txt[i] = new TextField(String.valueOf(0));
            increment[i] = new Button("+");
            increment[i].setOnAction(a-> updateTxtField(txt[i], 1));//assign handle 
            decrement[i] = new Button("-");
            decrement[i].setOnAction(a-> updateTxtField(txt[i],-1));
        }
    }
    //increment text filed value
    private void updateTxtField(TextField textField, int i) {

        int newValue = Integer.valueOf(textField.getText()) + i;
        textField.setText(String.valueOf(newValue));
    }

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

如有需要，请随时提出要求。如需更多帮助，post MCVE

Answer 2

经过一些实验，我想出了一个解决方案。请记住，这是我使用 Scene Builder、FXML 和 JavaFX 坚持使用 MVC 架构的尝试。

有 14 种不同的盘子，7 种以磅为单位，7 种以公斤为单位。每个板都有一个文本字段，用于显示对于给定的重量，每个板需要加载到杠铃上的数量。这些 textFields 存储在 ObservableLists 中，并在控制器的其他地方被赋予监听器。

// textFields associated with 45, 35, 25, 15, 10, 5, 2.5lb plates
ObservableList<TextField> poundTextFieldList = FXCollections.observableArrayList();
// textFields associated with 25, 20, 15, 10, 5, 2.5, 1.25kg plates
ObservableList<TextField> kilogramTextFieldList = FXCollections.observableArrayList();

这些数组存储盘子的数量。

int[] poundPlatesToLoad = calculator.getPoundPlatesToLoad();
int[] kilogramPlatesToLoad = calculator.getKilogramPlatesToLoad();

这些ArrayLists存储增量按钮

private final ArrayList<Button> poundIncrementButtons = new ArrayList();
private final ArrayList<Button> poundDecrementButtons = new ArrayList();
private final ArrayList<Button> kilogramIncrementButtons = new ArrayList();
private final ArrayList<Button> kilogramDecrementButtons = new ArrayList();

由于我使用了Scene Builder来设计GUI，所以每个按钮都需要@FXML标签来标识它们。我认为没有办法解决这个问题，所以控制器中有 28 个。

@FXML
private Button poundIncrement45Button;
@FXML
private Button poundDecrement45Button;

然后，为了避免编写 28 个处理程序，我编写了 4 个与每个 ArrayList 关联的处理程序。

public void poundIncrementButtonPressed(ActionEvent event) {
    System.out.println("pound increment button pressed");
    Button button = (Button) event.getSource();
    // identifies which plate is to be incremented
    int plate = poundIncrementButtons.indexOf(button);
    incrementDecrementPlate(0, 0, plate);
}

还有一种增加或减少正确文本字段的方法。

private void incrementDecrementPlate(int unit, int incrementDecrement, int textField) {

    int oldValue;
    if(unit == 0){
        oldValue = (int) poundPlatesToLoad[textField];
    } else {
        oldValue = (int) kilogramPlatesToLoad[textField];
    }

    String incremented;
    String decremented;

    if (oldValue % 2 != 0) {
        incremented = Integer.toString(oldValue + 1);
    } else {
        incremented = Integer.toString(oldValue + 2);
    }

    if (oldValue % 2 != 0) {
        decremented = Integer.toString(oldValue - 1);
    } else if (oldValue != 0) {
        decremented = Integer.toString(oldValue - 2);
    } else {
        decremented = Integer.toString(oldValue);
    }

    switch (unit) {
        case 0:
            if (incrementDecrement == 0) {
                poundTextFieldList.get(textField).setText(incremented);
            } else {
                poundTextFieldList.get(textField).setText(decremented);
            }
            break;
        case 1:
            if (incrementDecrement == 0) {
                kilogramTextFieldList.get(textField).setText(incremented);
            } else {
                kilogramTextFieldList.get(textField).setText(decremented);
            }
            break;
    }
}

这是到目前为止的程序图像。每个文本字段动态响应更改。右边的杠铃显示千克板以响应文本字段的变化。

如何在 Javafx 和 Scene Builder 中使用一个事件处理程序方法管理多个按钮

How to manage multiple buttons with one event handler method in Javafx and Scene Builder

java

javafx

fxml

scenebuilder

actionevent