Question

我使用重写的toString方法设置一个简单的随机生成的字符串，以显示从文本文件中检索的一些项目。我可以让它在控制台中显示得很好，但我还在学习GUI，目前正在使用内置GUI工具的NetBeans。我还有主要的类Automobile.java和一个单独的GUI.java类。我在GUI中有一个jTextArea，当我点击一个按钮时，我想要填充我打印到控制台的内容，但是我在开始使用它时遇到了麻烦。任何帮助，将不胜感激！谢谢！

注意：我已经在这里看了7或8个关于类似问题的其他讨论，但我仍然无法弄清楚。

import java.util.Scanner;
import java.util.ArrayList;
import java.util.Arrays;

class Automobile implements Comparable<Automobile> {

static java.util.Random randomGen = new java.util.Random();
static ArrayList<String> carMakes = new ArrayList<>();
static ArrayList<String> carModels = new ArrayList<>();
static SORTBY sortBy = SORTBY.MAKE;
static int nextUID = 1;
String make, model;
double engineSize = 0;
int doors = 0;
int invID = 0;

static {
    try {
        java.util.Scanner scFirst = new java.util.Scanner
            (new java.io.File("carMakes.txt"));
        java.util.Scanner scLast = new java.util.Scanner
            (new java.io.File("carModels.txt"));
        while (scFirst.hasNext()) {
            carMakes.add(scFirst.next());
        }
        while (scLast.hasNext()) {
            carModels.add(scLast.next());
        }
    } catch (java.io.FileNotFoundException e) {
        System.out.println(e);
    } // end try catch    
} // end static intializer        

enum SORTBY {
    MAKE, MODEL, DOORS, ENGINESIZE
}

public Automobile(String st) {
    this(new Scanner(st));
}

public Automobile(Scanner sc) {
    invID = nextUID++;
    make = sc.next();
    model = sc.next();
    doors = sc.nextInt();
    engineSize = sc.nextDouble();
} // end Scanner constructor        

public Automobile() {
    invID = nextUID++;
} // no parameter constructor        

public int compareTo(Automobile x) {
    switch (sortBy) {
        case MAKE:
            return make.compareTo(x.make);
        case MODEL:
            return model.compareTo(x.model);
        case DOORS:
            return doors - x.doors;
        case ENGINESIZE:
            return (engineSize > x.engineSize) ? 1 : -1;
    } // end switch      

    return 0;
} // end compareTo for Comparable interface        

public String toString() {
    return String.format
        ("%5d %15s %15s %5d %10.1fL", invID, make, model, doors, engineSize);
}// end method toString

public static Automobile[] makeRandom(int m) {
    Automobile[] auto = new Automobile[m];
    for (int i = 0; i < auto.length; i++) {
        auto[i] = new Automobile();
        auto[i].make = carMakes.get(randomGen.nextInt(carMakes.size()));
        auto[i].model = carModels.get(randomGen.nextInt(carModels.size()));
        auto[i].doors = randomGen.nextInt(6);
            if(auto[i].doors == 0 || auto[i].doors == 1)
                auto[i].doors = 2;
        auto[i].engineSize = randomGen.nextDouble() * 6.0;
            if(auto[i].engineSize <= 1.49)
                auto[i].engineSize = 1.5;
    } // end for each student to instantiate       
    return auto;
} // end method makeRandom

public static void main(String args[]) {
    System.out.println(new Automobile("X X 0 0.0"));
    Automobile[] x = makeRandom(5);
    for (Automobile m : x) {
        System.out.println(m);
    }
    Arrays.sort(x);
    System.out.println("---- Sorted By Make -----");
    for (Automobile m : x) {
        System.out.println(m);
    }
    System.out.println("---- Sorted By Model -----");
    Automobile.sortBy = SORTBY.MODEL;
    Arrays.sort(x);
    for (Automobile m : x) {
        System.out.println(m);
    }
    System.out.println("---- Sorted By Doors -----");
    Automobile.sortBy = SORTBY.DOORS;
    Arrays.sort(x);
    for (Automobile m : x) {
        System.out.println(m);
    }
    System.out.println("---- Sorted By Engine Size -----");
    Automobile.sortBy = SORTBY.ENGINESIZE;
    Arrays.sort(x);
    for (Automobile m : x) {
        System.out.println(m);
    }
} // end main

}

GUI类

Answer 1

如果我理解正确，您可以在GUI类中创建对JTextArea的静态引用。在创建一个按钮之后，你应该为它设置动作监听器并覆盖这样的actionPerformed方法（取消匿名内部类）：

JButton button = new JButton("Button");
    button.addActionListener(new ActionListener(){
        @Override
        public void actionPerformed(java.awt.event.ActionEvent e) {
            //adds text to the end of the document of the textArea
            MyClass.myTextArea.append(automobile.toString());
            //or
            //overrides the document of the textArea with your new string
            MyClass.myTextArea.setText(automobile.toString());
        }
});

Java GUI jTextArea在另一个类中填充toString方法

1 个答案: