Question

这可能是一个愚蠢的问题，可以通过更改我正在使用的布局来解决这个问题，但是，在运行我的计算器程序时，我很精明，直到我看到我的文本区域大小不会拉伸在没有我第一次创建它时设置尺寸的情况下自动调整窗格的大小，以及如何消除BorderLayout.CENTER在我的按钮面板之间占用的这个巨大差距？

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class calculatorProg extends JFrame implements ActionListener
{
    private Container contents;
    private JButton add, subtr, mult, div, pow, pow10, b1, b2, b3, b4, b5, b6, b7, b8, b9, b0;
    private JTextArea win;
    private JPanel numArea, win1, arithArea, numPlusArith;
    private JMenu men;
    private JMenuItem menItem;
    JSplitPane calcPane;

    public calculatorProg()
    {
        super("Calculator");
        contents = getContentPane();
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        contents.setLayout(new BorderLayout());

        //Arithmetic buttons
        add = new JButton("+");
        subtr = new JButton("-");
        mult = new JButton("x");
        div = new JButton("/");
        pow = new JButton("x^");
        pow10 = new JButton("x^10");

        //Buttons
        b1 = new JButton("1");
        b5 = new JButton("5");
        b2 = new JButton("2");
        b6 = new JButton("6");
        b3 = new JButton("3");
        b7 = new JButton("7");
        b4 = new JButton("4");
        b8 = new JButton("8");
        b9 = new JButton("9");
        b0 = new JButton("0");

        //Creating the panels
        win = new JTextArea(2, 25);
        win.setEditable(false);
        win.setVisible(true);
        win1 = new JPanel();
        win1.setLayout(new FlowLayout(FlowLayout.LEFT));
        win1.add(win);
        numArea = new JPanel(new GridLayout(0, 3));
        arithArea = new JPanel(new GridLayout(3, 3));
        arithArea.setSize(new Dimension(8, 8));
        numPlusArith = new JPanel(new BorderLayout());

        //Adding to num area
        numArea.add(b1);
        numArea.add(b2);
        numArea.add(b3);
        numArea.add(b4);
        numArea.add(b5);
        numArea.add(b6);
        numArea.add(b7);
        numArea.add(b8);
        numArea.add(b9);
        numArea.add(b0);
        arithArea.add(add);
        arithArea.add(subtr);
        arithArea.add(div);
        arithArea.add(mult);
        arithArea.add(pow);
        arithArea.add(pow10);
        numPlusArith.add(arithArea, BorderLayout.LINE_START);
        numPlusArith.add(numArea, BorderLayout.LINE_END);

        //Lay out the panes
        calcPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, win1, numPlusArith);
        calcPane.setOneTouchExpandable(true);
        calcPane.setDividerLocation(50);

        Dimension minimumSize = new Dimension(100, 50);
        win1.setMinimumSize(minimumSize);
        numArea.setMinimumSize(minimumSize);

        //add to contents
        contents.add(calcPane, BorderLayout.CENTER);

        setSize(320, 370);
        setVisible(true);
    }

    public static void main(String[] args)
    {
        calculatorProg cp = new calculatorProg();
    }
}

有人可能会提到numArea中的0偏离中心（我在Java文档中读到了GridBagLayout但是我的脚趾还没有进入那些水域的一半。）< / p>

编辑代码：

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

class calculatorProg extends JFrame implements ActionListener {
private Container contents;
private JButton add, subtr, mult, div, pow, pow10, clr, plmi, b1, b2, b3, b4, b5,   b6, b7, b8, b9, b0;
private JTextArea win;
private JPanel numArea, win1, arithArea, numPlusArith;
private JMenu men;
private JMenuItem menItem;
JSplitPane calcPane;

public calculatorProg(){
    super("Calculator");
contents = getContentPane();
setDefaultCloseOperation(EXIT_ON_CLOSE);
contents.setLayout(new BorderLayout());

//Arithmetic buttons
add = new JButton("+");
subtr = new JButton("-");
mult = new JButton("x");
div = new JButton("/");
pow = new JButton("x^");
pow10 = new JButton("x^10");


//Buttons
b1 = new JButton("1"); b5 = new JButton("5");
b2 = new JButton("2"); b6 = new JButton("6");   
b3 = new JButton("3"); b7 = new JButton("7");
b4 = new JButton("4"); b8 = new JButton("8");
b9 = new JButton("9"); b0 = new JButton("0");
clr = new JButton("C"); plmi = new JButton("+/-");


//Creating the panels
win = new JTextArea(2, 25);
win.setLineWrap(true);
win.setWrapStyleWord(true);
win.setEditable(false);
win.setVisible(true);
win1 = new JPanel();
win1.setLayout(new BorderLayout());
win1.add(new JScrollPane(win), BorderLayout.CENTER);
numArea = new JPanel(new GridLayout(0,3));
arithArea = new JPanel(new GridLayout(3, 3));
//arithArea.setSize(new Dimension(8, 8));
numPlusArith = new JPanel(new GridLayout(0, 2, 0, 0));

//Adding to num area
numArea.add(b1); numArea.add(b2);
numArea.add(b3); numArea.add(b4);
numArea.add(b5); numArea.add(b6);
numArea.add(b7); numArea.add(b8);
numArea.add(b9); numArea.add(b0); 
numArea.add(clr); numArea.add(plmi);
arithArea.add(add);
arithArea.add(subtr);
arithArea.add(div);
arithArea.add(mult);
arithArea.add(pow);
arithArea.add(pow10);
numPlusArith.add(arithArea);
numPlusArith.add(numArea);

//Lay out the panes
calcPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, win1, numPlusArith);
calcPane.setOneTouchExpandable(true);
calcPane.setDividerLocation(50);

Dimension minimumSize = new Dimension(100, 50);
win1.setMinimumSize(minimumSize);
numArea.setMinimumSize(minimumSize);

//add to contents
contents.add(calcPane, BorderLayout.CENTER);

pack();
setVisible(true);

}
public static void main(String[] args) {
    calculatorProg cp = new calculatorProg();

}

private double addition(double a, double b){
    a=0.0; b=0.0;
    double finAnswer = a + b;

    return finAnswer;
}
private double subtraction(double a, double b){
    a=0.0; b=0.0;
    double finAnswer = a + b;

    return finAnswer;
}
private double division(double a, double b){
    a=0.0; b=0.0;
    double finAnswer = a / b;

    return finAnswer;
}
private double multiplication(double a, double b){
    a=0.0; b=0.0;
    double finAnswer = a * b;
    return finAnswer;
}
private double pow(double a, double b){
    a=0.0; b=0.0;
    double finAnswer = Math.pow(a, b);
    return finAnswer;
}
private double pow10(double a){
    a = 0.0;
    double finAnswer = Math.pow(a, 10);

    return finAnswer;
}
@Override
public void actionPerformed(ActionEvent arg0) {
    // TODO Auto-generated method stub

}

}

如你所见，我做了急需的改变。它看起来更清洁。数字区域周围仍然存在微小差距，但仍然更清洁。 pack()肯定会有所作为。感谢所有帮助人员！

Answer 1

感谢SSCCE，+1。所有缺少的是actionPerformed方法（在最近的编辑之前，您也错过了最后一个}。

在任何情况下，您的问题都在于FlowLayout用于包含JTextArea的面板。改变这些行：

win1.setLayout(new FlowLayout(FlowLayout.LEFT));
win1.add(win);

到此：

win1.setLayout(new BorderLayout());
win1.add(new JScrollPane(win), BorderLayout.CENTER);

您可能还注意到我将文本区域包装在滚动窗格中。这将使任何文本溢出都可滚动。您还应添加以下行以打开换行：

win = new JTextArea(2, 25);
win.setLineWrap(true);
win.setWrapStyleWord(true);

如何消除BorderLayout.CENTER占用的差距？

1 个答案: