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I am trying to make a GUI of a calculator which solves Parallel and Perpendicular Equations. It works when the GUI is not implemented but when I implement the GUI there are errors coming out such as nullpointerexception and numberformatexception. please do help me in resolving this.
我正在尝试制作一个解决平行和垂直方程的计算器的GUI。它在未实现GUI时工作,但是当我实现GUI时,会出现诸如nullpointerexception和numberformatexception之类的错误。请帮我解决这个问题。
import java.awt.*;
public class SuntayProjGUI {
公共课SuntayProjGUI {
JFrame frame;
private JTextField Ax;
private JTextField By;
private JTextField C;
private JTextField slopeLine;
private JTextField yintLine;
BigDecimal xCoefficient, yCoefficient, b, slope1, slope2, yIntercept1, yIntercept2, xCoord, yCoord; // declaration. Obvious naman na 'to
/**
* Launch the application.
* @param args
* @wbp.parser.entryPoint
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
SuntayProjGUI window = new SuntayProjGUI();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* @wbp.parser.entryPoint
*/
public SuntayProjGUI(){
initialize();
}
public void initialize(){
frame = new JFrame();
frame.getContentPane().setBackground(Color.PINK);
frame.getContentPane().setLayout(null);
Ax = new JTextField();
Ax.setBounds(46, 142, 116, 22);
frame.getContentPane().add(Ax);
Ax.setColumns(10);
By = new JTextField();
By.setBounds(46, 191, 116, 22);
frame.getContentPane().add(By);
By.setColumns(10);
C = new JTextField();
C.setBounds(46, 191, 116, 22);
frame.getContentPane().add(C);
C.setColumns(10);
JLabel lblPleaseChooseWhat = new JLabel("Please choose what inputs this calculator will receive");
lblPleaseChooseWhat.setBounds(12, 44, 302, 16);
frame.getContentPane().add(lblPleaseChooseWhat);
JComboBox comboBox = new JComboBox();
comboBox.setBounds(22, 76, 147, 22);
comboBox.addItem("Line with Y-intercept");
comboBox.addItem("Line with Point");
frame.getContentPane().add(comboBox);
//Computations
xCoefficient = new BigDecimal(Ax.getText());
yCoefficient = new BigDecimal(By.getText());
b = new BigDecimal(C.getText());
slope1 = getSlope(xCoefficient, yCoefficient);
yIntercept1 = getYIntercept(yCoefficient, b);
JLabel lblA = new JLabel("A :");
lblA.setBounds(12, 148, 36, 16);
frame.getContentPane().add(lblA);
JLabel lblB = new JLabel("B:");
lblB.setBounds(12, 194, 56, 16);
frame.getContentPane().add(lblB);
JLabel lblC = new JLabel("C:");
lblC.setBounds(12, 240, 56, 16);
frame.getContentPane().add(lblC);
C = new JTextField();
C.setBounds(46, 237, 116, 22);
frame.getContentPane().add(C);
C.setColumns(10);
JLabel lblLineAx = new JLabel("Line: Ax + By = C");
lblLineAx.setBounds(12, 111, 137, 16);
frame.getContentPane().add(lblLineAx);
JButton btnEnter = new JButton("Enter");
btnEnter.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
frame.setVisible(false);
if(comboBox.equals("Line with Y-intercept")){
Line_with_yint lwy = new Line_with_yint();
lwy.frame.setVisible(true);
}
else if(comboBox.equals("Line with Point")){
Line_with_point lwp = new Line_with_point();
lwp.frame.setVisible(true);
}
}
});
btnEnter.setBounds(217, 383, 97, 25);
frame.getContentPane().add(btnEnter);
JLabel lblSlopeOfThe = new JLabel("Slope of the Line: ");
lblSlopeOfThe.setBounds(12, 291, 114, 16);
frame.getContentPane().add(lblSlopeOfThe);
slopeLine = new JTextField();
slopeLine.setEnabled(false);
slopeLine.setEditable(false);
slopeLine.setBounds(151, 288, 116, 22);
frame.getContentPane().add(slopeLine);
slopeLine.setColumns(10);
slopeLine.setText(slope1.toString());
JLabel lblYinterceptOfThe = new JLabel("Y-Intercept of the Line:");
lblYinterceptOfThe.setBounds(12, 332, 137, 16);
frame.getContentPane().add(lblYinterceptOfThe);
yintLine = new JTextField();
yintLine.setEnabled(false);
yintLine.setEditable(false);
yintLine.setBounds(151, 329, 116, 22);
frame.getContentPane().add(yintLine);
yintLine.setColumns(10);
yintLine.setText(yIntercept1.toString());
JButton btnCalculate = new JButton("Calculate");
btnCalculate.setBounds(217, 236, 97, 25);
frame.getContentPane().add(btnCalculate);
}
public static BigDecimal getSlope(BigDecimal x, BigDecimal y)
{
y = y.multiply(new BigDecimal(-1)); // yung pagmultiply sa -1 yung pagtranspose ng Ax + By = C -> By = -Ax + C
y = x.divide(y, 4, RoundingMode.CEILING); // eto yung pagdivide nung coefficient ni y sa both sides ng equation -> y = -Ax/B + C/B
return y;
}
public static BigDecimal getReciprocalSlope(BigDecimal x, BigDecimal y)
{
y = y.divide(x, 4, RoundingMode.CEILING).multiply(new BigDecimal(-1)); // eto yung reciprocal. obviously. balaiktarin lang. kung kanina
return y;
}
public static BigDecimal getYIntercept(BigDecimal y, BigDecimal b)
{
b = b.divide(y, 4, RoundingMode.CEILING); // yung pagkuha ng y-intercept similar dun sa getSlope pero ang difference since walang transposition, divide lang.
return b;
}
public static void getGEandSE(BigDecimal slope, BigDecimal xCoord, BigDecimal yCoord, BigDecimal yIntercept, BigDecimal x, BigDecimal y)
{
BigDecimal parallelA, parallelB, parallelC, perpendicularA, perpendicularB, perpendicularC;
if (x.compareTo(BigDecimal.ZERO) < 0) // itong part na 'to, kapag yung divisor (kasi diba either si y or x yung divisor, kapag slope na normal, si y, kapag nirereciprocate for perpendicular, si x diba.) negative, gagawing positive since lagi namang positive kapag nagdidivide both sides diba
x = x.multiply(new BigDecimal(-1));
if (y.compareTo(BigDecimal.ZERO) < 0)
y = y.multiply(new BigDecimal(-1));
if (yIntercept == null)
{
yCoord = yCoord.multiply(new BigDecimal(-1));
xCoord = xCoord.multiply(new BigDecimal(-1));
parallelA = slope.multiply(y).multiply(new BigDecimal(-1)); // eto yung diba kapag points ang given, y - y1 = m(x - x1). Yung coefficient ni x kasi si parallelA tapos transpose kaya may -1 tapos para mawala yung fraction, mumultiply by y. Gets naman kung bakit diba? Dito nagaganap yung -mx + y - y1 = mx1
parallelC = (xCoord.multiply(slope).multiply(new BigDecimal(-1))).add(yCoord).multiply(y); // kapag si C naman, diba y - y1 = m(x - x1) dito nagaganap yung didistribute si M tsaka ttranspose sa kabila. From y -y1 = m(x - x1) -> y - y1 + mx1 = mx
perpendicularA = getReciprocalSlope(x, y).multiply(x).multiply(new BigDecimal(-1)); // same principle lang, difference lang neto yung imbis na slope yung mumultiply, yung reciprocal nya (yung function dun na reciprocalSlope)
perpendicularC = (xCoord.multiply(getReciprocalSlope(x, y).multiply(new BigDecimal(-1))).add(yCoord)).multiply(x);
if (parallelC.compareTo(BigDecimal.ZERO) > 0)
System.out.println("Parallel Line GE: " + parallelA + "x + " + y + "y + " + parallelC + " = 0");
else
System.out.println("Parallel Line GE: " + parallelA + "x + " + y + "y - " + parallelC.multiply(new BigDecimal(-1)) + " = 0");
System.out.println("Parallel Line SE: " + parallelA + "x + " + y + "y = " + parallelC);
if (perpendicularC.compareTo(BigDecimal.ZERO) > 0)
System.out.println("Perpendicular Line GE: " + perpendicularA + "x + " + x + "y + " + perpendicularC + " = 0");
else
System.out.println("Perpendicular Line GE: " + perpendicularA + "x + " + x + "y - " + perpendicularC.multiply(new BigDecimal(-1)) + " = 0");
System.out.println("Perpendicular Line SE: " + perpendicularA + "x + " + x + "y = " + perpendicularC.multiply(new BigDecimal(-1)));
}
else
{
parallelA = slope.multiply(new BigDecimal(-1)).multiply(y); // gets mo na siguro 'to. Kung ano nasa notes mo at yung pagkakahawig nya sa nasa taas ganun din
parallelC = yIntercept.multiply(new BigDecimal(-1)).multiply(y);
perpendicularA = getReciprocalSlope(x, y).multiply(new BigDecimal(-1)).multiply(x);
perpendicularC = yIntercept.multiply(new BigDecimal(-1)).multiply(x);
if (parallelC.compareTo(BigDecimal.ZERO) > 0)
System.out.println("Parallel Line GE: " + parallelA + "x + " + y + "y + " + parallelC + " = 0");
else
System.out.println("Parallel Line GE: " + parallelA + "x + " + y + "y - " + parallelC.multiply(new BigDecimal(-1)) + " = 0");
System.out.println("Parallel Line SE: " + parallelA + "x + " + y + "y = " + parallelC.multiply(new BigDecimal(-1)));
if (perpendicularC.compareTo(BigDecimal.ZERO) > 0)
System.out.println("Perpendicular Line GE: " + perpendicularA + "x + " + x + "y + " + perpendicularC + " = 0");
else
System.out.println("Perpendicular Line GE: " + perpendicularA + "x + " + x + "y - " + perpendicularC.multiply(new BigDecimal(-1)) + " = 0");
System.out.println("Perpendicular Line SE: " + perpendicularA + "x + " + x + "y = " + perpendicularC);
}
}
}
and when I try to run this, there are errors:
当我尝试运行它时,有错误:
java.lang.NumberFormatException
at java.math.BigDecimal.<init>(BigDecimal.java:596)
at java.math.BigDecimal.<init>(BigDecimal.java:383)
at java.math.BigDecimal.<init>(BigDecimal.java:806)
at SuntayProjGUI.initialize(SuntayProjGUI.java:83)
at SuntayProjGUI.<init>(SuntayProjGUI.java:47)
at SuntayProjGUI$1.run(SuntayProjGUI.java:34)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
thank you for answering
谢谢你的回答
2 个解决方案
#1
1
You'r trying to get a text from a text box which should be empty after initializing. Therefore you'r calling new BigDecimal("") which will throw an NumberFormatException. The NullpointerException will probably get thrown because new BigDecimal failed to create an Object. You need to do the computations after the fields got filled.
您试图从文本框中获取文本,该文本框在初始化后应为空。因此,您调用新的BigDecimal(“”)将抛出NumberFormatException。 NullpointerException可能会被抛出,因为新的BigDecimal无法创建Object。在填写字段后,您需要进行计算。
EDIT: Also it looks like C hasn't been initialized at this point of code.
编辑:此外看起来C尚未在此代码点初始化。
xCoefficient = new BigDecimal(Ax.getText());
yCoefficient = new BigDecimal(By.getText());
b = new BigDecimal(C.getText());
EDIT2: You could move everything which should only be done after entering values into a method and call this method via a button.
编辑2:您可以移动所有应该只在将值输入方法后完成并通过按钮调用此方法。
#2
0
@Nordiii already explained the reason behind your problem. So, i am not repeating it.
@Nordiii已经解释了你的问题背后的原因。所以,我不是在重复它。
The computation part of your code should be in actionPerformed method of your Calculate Button.
代码的计算部分应该是Calculate Button的actionPerformed方法。
EDIT:
btnCalculate.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent arg0)
{
xCoefficient = new BigDecimal(Ax.getText());
yCoefficient = new BigDecimal(By.getText());
b = new BigDecimal(C.getText());
slope1 = getSlope(xCoefficient, yCoefficient);
yIntercept1 = getYIntercept(yCoefficient, b);
slopeLine.setText(slope1.toString());
yintLine.setText(yIntercept1.toString());
}
});
Also set default frame size
还设置默认帧大小
frame.setBounds(100, 100, 468, 369);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
#1
1
You'r trying to get a text from a text box which should be empty after initializing. Therefore you'r calling new BigDecimal("") which will throw an NumberFormatException. The NullpointerException will probably get thrown because new BigDecimal failed to create an Object. You need to do the computations after the fields got filled.
您试图从文本框中获取文本,该文本框在初始化后应为空。因此,您调用新的BigDecimal(“”)将抛出NumberFormatException。 NullpointerException可能会被抛出,因为新的BigDecimal无法创建Object。在填写字段后,您需要进行计算。
EDIT: Also it looks like C hasn't been initialized at this point of code.
编辑:此外看起来C尚未在此代码点初始化。
xCoefficient = new BigDecimal(Ax.getText());
yCoefficient = new BigDecimal(By.getText());
b = new BigDecimal(C.getText());
EDIT2: You could move everything which should only be done after entering values into a method and call this method via a button.
编辑2:您可以移动所有应该只在将值输入方法后完成并通过按钮调用此方法。
#2
0
@Nordiii already explained the reason behind your problem. So, i am not repeating it.
@Nordiii已经解释了你的问题背后的原因。所以,我不是在重复它。
The computation part of your code should be in actionPerformed method of your Calculate Button.
代码的计算部分应该是Calculate Button的actionPerformed方法。
EDIT:
btnCalculate.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent arg0)
{
xCoefficient = new BigDecimal(Ax.getText());
yCoefficient = new BigDecimal(By.getText());
b = new BigDecimal(C.getText());
slope1 = getSlope(xCoefficient, yCoefficient);
yIntercept1 = getYIntercept(yCoefficient, b);
slopeLine.setText(slope1.toString());
yintLine.setText(yIntercept1.toString());
}
});
Also set default frame size
还设置默认帧大小
frame.setBounds(100, 100, 468, 369);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);