问题描述
所以，现在我正在尝试用 Java 构建一个计算器，我已经构建了 GUI，但是我找不到从窗格中获取文本并对其进行必要数学运算的方法。 例子 文本窗格说
1 + 2
1 + 2 = 3
我试过获取文本并使用 parseInt、parseFloat 和 parseDouble。每次我尝试将文本转换为 Int、Double 或 Float 时，都会出现错误。错误说
“线程“AWT-EventQueue-0”中的异常java.lang.NumberFormatException：对于输入字符串：“1 + 1””
关于我可以做什么的任何想法
代码：
import java.awt.Color;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextPane;
//General information: SOL is a
//Sorry for what I'm sure is sloppy code I'm new to programming
public class MathDoer_Main {
//initializing all of the frames,the text pane,key listeners,the ScrollPane,and all of the buttons
public static JFrame mathDoerFrame = new JFrame("mathDoer");
public static JTextPane mathDoerText = new JTextPane();
public static JScrollPane mathDoerTextScoll = new JScrollPane();
public static JTextPane mathDoerConsole = new JTextPane();
public static JScrollPane mathDoerConsoleScroll = new JScrollPane();
public static JButton mathDoer0Button;
public static JButton mathDoerClearButton = new JButton("Clear");
public static JButton mathDoerDecimalButton;
public static JButton mathDoer1Button;
public static JButton mathDoer2Button;
public static JButton mathDoer3Button;
public static JButton mathDoer4Button;
public static JButton mathDoer5Button;
public static JButton mathDoer6Button;
public static JButton mathDoer7Button;
public static JButton mathDoer8Button;
public static JButton mathDoer9Button;
public static JButton mathDoerDivideButton;
public static JButton mathDoerMultiplyButton;
public static JButton mathDoerAdditionButton;
public static JButton mathDoerSubtractionButton;
public static JButton mathDoerNegitiveButton;
public static JButton mathDoerFormulaButton;
public static JButton mathDoerAlphaButton;
public static JButton mathDoerBetaButton;
public static JButton mathDoerGammaButton;
public static JButton mathDoerDeltaButton;
public static JButton mathDoerThirdButton;
public static JButton mathDoerEqualButton;
public static JButton mathDoerStartParentheses;
public static JButton mathDoerEndParentheses;
public static JButton mathDoerCaretKey;
public static JButton mathDoerMainScreen;
public static MathDoerKeyListener sea_MathDoerKeyListener;
public static void main(String[] args) {
//These integers are used to set the size of the frame,and the textPane
int mathDoerWidth = 397;
int mathDoerHeight = 527;
int mathDoerTextWidth = mathDoerHeight - 1 - 71;
//This keyListener just adds keyBoard Controls for each button (I.E. 1,2,3,4,5,6,7,8,9,/,*,-,+,Clear,Enter)
sea_MathDoerKeyListener = new MathDoerKeyListener();
//Defining everything to do with the frame,textPane,and scrollPane
mathDoerFrame.setSize(mathDoerWidth,mathDoerHeight);
mathDoerFrame.setLocationRelativeto(null);
mathDoerFrame.setLayout(null);
mathDoerFrame.setDefaultCloSEOperation(2);
mathDoerFrame.setResizable(true);
mathDoerFrame.getContentPane().setBackground(new Color(0,0));
mathDoerFrame.addKeyListener(sea_MathDoerKeyListener);
mathDoerFrame.setResizable(false);
mathDoerFrame.setVisible(true);
//This text is the History
mathDoerFrame.add(mathDoerText);
mathDoerText.setBackground(new Color(15,15,15));
mathDoerText.setForeground(new Color(200,200,200));
mathDoerText.setFont(new Font("Courier New",Font.PLAIN,12));
mathDoerText.setEditable(false);
mathDoerText.addKeyListener(sea_MathDoerKeyListener);
mathDoerTextScoll.setVisible(true);
mathDoerTextScoll = new JScrollPane();
mathDoerTextScoll.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_NEVER);
mathDoerTextScoll.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
mathDoerTextScoll.setBounds(1,1,mathDoerTextWidth,88);
mathDoerTextScoll.getViewport().add(mathDoerText);
mathDoerTextScoll.setBorder(null);
mathDoerFrame.add(mathDoerTextScoll);
//This text is the one the buttons are editing
mathDoerFrame.add(mathDoerConsole);
mathDoerConsole.setBackground(new Color(15,15));
mathDoerConsole.setForeground(new Color(200,200));
mathDoerConsole.setFont(new Font("Courier New",12));
mathDoerConsole.setEditable(true);
mathDoerConsole.addKeyListener(sea_MathDoerKeyListener);
mathDoerConsoleScroll.setVisible(true);
mathDoerConsoleScroll.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_NEVER);
mathDoerConsoleScroll.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
mathDoerConsoleScroll.setBounds(1,89,18);
mathDoerConsoleScroll.getViewport().add(mathDoerConsole);
mathDoerConsoleScroll.setBorder(null);
mathDoerFrame.add(mathDoerConsoleScroll);
//Used to make a grid system for the buttons
int buttonSize = 75;
int column = buttonSize + 1;
int row = buttonSize + 1;
//Defining all of the Necessary Things for the button (for the Method(I think that's the right term) see line 184)
mathDoerDecimalButton = initButton(column*3+1,row*4+108,buttonSize,".",new Color(10,15),new Color(200,200),true);
mathDoerNegitiveButton = initButton(column*1+1,"-/+",true);
mathDoer0Button = initButton(column*2+1,"0",true);
mathDoer1Button = initButton(column*1+1,row*3+108,"1",true);
mathDoer2Button = initButton(column*2+1,"2",true);
mathDoer3Button = initButton(column*3+1,"3",true);
mathDoer4Button = initButton(column*1+1,row*2+108,"4",true);
mathDoer5Button = initButton(column*2+1,"5",true);
mathDoer6Button = initButton(column*3+1,"6",true);
mathDoer7Button = initButton(column*1+1,row*1+108,"7",true);
mathDoer8Button = initButton(column*2+1,"8",true);
mathDoer9Button = initButton(column*3+1,"9",true);
mathDoerDivideButton = initButton(column*4+1,row*0+108," / ",new Color(15,10,true);
mathDoerMultiplyButton = initButton(column*4+1," * ",true);
mathDoerAdditionButton = initButton(column*4+1," + ",true);
mathDoerSubtractionButton = initButton(column*4+1," - ",true);
mathDoerAlphaButton = initButton(column*0+1,"α",10),false);
mathDoerBetaButton = initButton(column*0+1,"β",false);
mathDoerGammaButton = initButton(column*0+1,"γ",false);
mathDoerDeltaButton = initButton(column*0+1,"δ",false);
mathDoerEqualButton = initButton(column*4+1," = ",false);
mathDoerClearButton = initButton(column*0+1,"Clear",false);
mathDoerStartParentheses = initButton(column*1+1," ( ",true);
mathDoerEndParentheses = initButton(column*2+1," ) ",true);
mathDoerCaretKey = initButton(column*3+1," ^ ",true);
//These the specialized buttons when pressed
mathDoerAlphaButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("Formula Screen");
}
});
mathDoerEqualButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
calculate();
}
});
mathDoerClearButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
mathDoerConsole.setText("");
System.out.println("clear");
}
});
}
public static JButton initButton(int x,int y,int width,int height,String text,Color backgroundColor,Color foregroundColor,boolean defaultAction) {
JButton button = new JButton(text);
mathDoerFrame.add(button);
button.setBounds(x,y,width,height);
button.setBackground(backgroundColor);
button.setForeground(foregroundColor);
button.setBorderPainted(false);
button.addKeyListener(sea_MathDoerKeyListener);
if (defaultAction) {
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println(button.getText());
mathDoerConsole.setText(mathDoerConsole.getText() + button.getText());
}
});
}
return button;
}
//The method is the main calculation
public static void calculate() {
System.out.println(mathDoerConsole.getText());
double math = Double.parseDouble(mathDoerConsole.getText());
System.out.println(Double.toString(math));
}
}
如果您需要更多信息，请随时告诉我，或询问
解决方法
如果我理解正确，您是在尝试将字符串“1+1”转换为整数。 “+”不是整数而是整数运算。我建议您将字符串正确解析为“操作中的整数”和“操作”，然后进行相应的计算。