如何爲在循環中創建的100個文本字段創建changeListener？

Question

我創建了100個文本字段並將它們放入gridPane。用戶可以更改任何文本字段中的值。我需要能夠註冊該更改的值，以便我的按鈕能夠找到最大尺寸的子平方將正常工作。由於文本字段是在循環中創建的，因此我堅持如何在任何單獨的文本字段中偵聽更改。

import javafx.application.Application; 
import javafx.geometry.Insets; 
import javafx.geometry.Pos; 
import javafx.scene.Scene; 
import javafx.scene.control.Button; 
import javafx.scene.control.TextField; 
import javafx.scene.layout.GridPane; 
import javafx.scene.layout.StackPane; 
import javafx.scene.paint.Paint; 
import javafx.stage.Stage; 

import static java.lang.Math.rint; 


public class Exercise22_19 extends Application { 
    //declare a gridpane here so that methods have easy access 
    GridPane gp1; 
    int[][] valList; 
    @Override 
    public void start(Stage primaryStage) { 

     //stack pane to hold the gridpane; makes it easy to keep the grid 
     //centered in the stage 
     StackPane root = new StackPane(); 

     ///gridpane to hold the 10x10 matrix of textfields 
     gp1 = new GridPane(); 
     gp1.setPadding(new Insets(5, 5, 5, 5)); 
     //center the gridpane in the stackpane 
     gp1.setAlignment(Pos.CENTER); 
     root.getChildren().add(gp1); 
     setNumbers(); 

     //refresh button: refills matrix with new values 
     Button refreshBt = new Button("Refresh"); 
     //call the function to reset the values in the matrix when the refresh 
     //button is clicked 
     refreshBt.setOnAction(e -> setNumbers()); 

     //findLargestBlock button finds the largest square block of 1's in the 
     //matrix 
     Button lrgBlkBt = new Button("Find Largest Button"); 
     //call the function to find the largest square block of 1's when the 
     //find button is clicked 
     lrgBlkBt.setOnAction(e -> findBigBlock()); 

     //makes a space between the last row of numbers and the buttons. Even 
     //though it is onle set on one button, it affects the entire row 
     GridPane.setMargin(refreshBt, new Insets(5, 5, 5, 5)); 

     //add buttons to gridpane 
     //refresh spans 3 columns 
     gp1.add(refreshBt, 1, 10, 3, 1); 
     //find spans 6 columns 
     gp1.add(lrgBlkBt, 4, 10, 6, 1); 

     Scene scene = new Scene(root); 
     primaryStage.setTitle("Exercise 22_19 (Dynamic)"); 
     primaryStage.setScene(scene); 
     primaryStage.show(); 
    } 

    //set all textfield values in the matrix to 0 or 1 
    public void setNumbers() { 
     //gridpane does not have a method to access the value of a node in the 
     //gridpane, so I will store the values in an array. 
     valList = new int[10][10]; 
     for (int i = 0; i < 10; i++) { 
      for (int k = 0; k < 10; k++) { 
       TextField tf = new TextField(); 
       tf.setPrefWidth(25); 
       //set the value of the text field to 0 or 1 
       //create a random 0 or 1 integer 
       int val = (int)(rint(Math.random())); 
       //fill the array with the values 
       valList[i][k] = val; 
       String valStr = String.valueOf(val); 
       tf.setText(valStr); 
       //add text fields to gridpane 
       GridPane.setConstraints(tf, k, i); 
       gp1.getChildren().add(tf); 
      } 

     } 
    } 

    //find the largest square block of 1's in the matrix 
    public void findBigBlock() { 
     //size of square matrix 
     int n = 10; 
     //max tells the size of the largest square sub-maxtrix, e.g. if max==3, 
     //the largest sub-matrix is a 3x3 matrix 
     int max = 0; 
     int maxRow = 0; 
     int maxCol = 0; 
     //color for the textbox; red 
     Paint tfColor = Paint.valueOf("FF0000"); 

     int[][] arr = new int[10][10]; 
     //copy first row to new array 
     System.arraycopy(valList[0], 0, arr[0], 0, 10); 
     //copy first col to new array 
     for (int i = 0; i < n; i++) { 
      arr[i][0] = valList[i][0]; 
     } 

     //determines the size and location of the maximum sub-square 
     for (int row = 1; row < n; row++) { 
      for (int col = 1; col < n; col++) { 
       if (valList[row][col] == 1) { 
        arr[row][col] =((Math.min(valList[row][col-1], 
          (Math.min(valList[row-1][col], valList[row-1][col-1])))) + 1); 
        if (arr[row][col] >= max) { 
         max = arr[row][col]; 
         maxRow = row; 
         maxCol = col; 
        } 
       } 
       else 
        arr[row][col] = 0; 
      } 
     } 

     //replaces the normal textfields with red textfields for the maximum 
     //sub-square 
     for (int i = max; i > 0; i--) { 
      for (int j = maxRow; j > maxRow - max; j--) { 
       for (int k = maxCol; k > maxCol - max; k--) { 
        //create a nex textfield 
        TextField tf = new TextField(); 
        tf.setPrefWidth(25); 
        //set color to red 
        tf.setStyle("-fx-control-inner-background: #"+tfColor.toString().substring(2)); 
        tf.setText(String.valueOf(valList[j][k])); 
        //put the red textfield into the gridpane 
        GridPane.setConstraints(tf, k, j); 
        gp1.getChildren().add(tf); 
       } 
      } 
     } 
    } 

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

Answer 1

像這樣的工作你的情況：

public void setNumbers() { 
    //gridpane does not have a method to access the value of a node in the 
    //gridpane, so I will store the values in an array. 
    valList = new int[10][10]; 
    for (int i = 0; i < 10; i++) { 
     for (int k = 0; k < 10; k++) { 
      TextField tf = new TextField(); 
      tf.setPrefWidth(25); 
      //set the value of the text field to 0 or 1 
      //create a random 0 or 1 integer 
      int val = (int)(rint(Math.random())); 
      //fill the array with the values 
      valList[i][k] = val; 
      String valStr = String.valueOf(val); 
      tf.setText(valStr); 
      //add text fields to gridpane 
      GridPane.setConstraints(tf, k, i); 
      gp1.getChildren().add(tf); 

      tf.textProperty().addListener((observable, oldValue, newValue) -> { 
       valList[GridPane.getRowIndex(tf)][GridPane.getColumnIndex(tf)] = Integer.parseInt(newValue); 
      }); 
     } 

    } 
} 

注意，你應該添加類型檢查領域，如so