问题
I'm making a simple (and bogus) computer power consumption calculator. I'm using a card layout to put multiple panels in but when I run it, there's just a small window not displaying anything. Here's my long code, I put it all in one class.
package my.Project;
import java.awt.*;
import java.awt.event.*;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.text.DecimalFormat;
import javax.swing.*;
public class MainProject extends JFrame {
CardLayout cl;
int motherboardP, oddP, hddP, ssdP, fanP, cpuP, gpuP, monitorP, hoursint;
int ramNum, hddNum, ssdNum, fanNum, gpuNum;
double ramP, totalP, powerPerYear;
public float tariff = (float) 0.2180;
public float costRM;
JPanel mainPage, secondPage, thirdPage, results;
//JPanel panelCont;
JLabel title, icon, motherboard, ram, numram,
numssd, numhdd, odd, numfan, cpu, gpu,
numgpu, monitor, hours, outage, peryear,
costyear, watt, kwatt, rm;
JButton start, exit1, exit2, nxt1, bck1, nxt2, bck2, done, bck3, tips, calc;
JTextField numRam, numSSD, numHDD, numFan, numGpu, hoursUse,
outagePC, perYear, cost;
JComboBox mboardBox, ramBox, oddBox, cpuBox, gpuBox,
monitorBox;
public MainProject() {
initComponents();
}
public void initComponents() {
setTitle("Power Consumption Calculator");
setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(500, 400);
Container contentPane = getContentPane();
contentPane.setLayout(cl);
/*
panelCont = new JPanel();
cl = new CardLayout();
*/
//contentPane.add(panelCont);
/*
panelCont.setLayout(cl);
panelCont.add(mainPage,"1");
panelCont.add(secondPage,"2");
panelCont.add(thirdPage,"3");
panelCont.add(results,"4");
cl.show(panelCont,"1");
*/
mainPage = new JPanel();
secondPage = new JPanel();
thirdPage = new JPanel();
results = new JPanel();
cl.show(contentPane,"1");
contentPane.add("1", mainPage);
contentPane.add("2", secondPage);
contentPane.add("3", thirdPage);
contentPane.add("4", results);
title.setFont(new Font("Tahoma", Font.BOLD, 18));
title.setText("Computer Power Consumption Calculator");
motherboard.setText("Motherboard:");
ram.setText("RAM:");
numram.setText("No. of RAM Sticks:");
numssd.setText("Num. of SSD:");
numhdd.setText("Num. of HDD:");
odd.setText("Optical Disk Drive:");
numfan.setText("Num. of Fans:");
cpu.setText("CPU:");
gpu.setText("GPU:");
numgpu.setText("Num. of GPU:");
monitor.setText("Monitor:");
hours.setText("Hours of usage/day:");
outage.setText("PC Power Outage:");
peryear.setText("Per year:");
costyear.setText("Cost/year");
watt.setText("Watts (W)");
kwatt.setText("kiloWatts(kW)");
rm.setText("RM");
icon.setIcon(new javax.swing.ImageIcon(getClass().getResource("/my/Project/pclogo.png")));
BorderLayout mainL = new BorderLayout();
mainPage.setLayout(mainL);
mainPage.add(title, BorderLayout.PAGE_START);
mainPage.add(icon, BorderLayout.CENTER);
mainPage.add(start, BorderLayout.SOUTH);
mainPage.add(exit1,BorderLayout.SOUTH);
GridLayout secondL = new GridLayout(0,2);
secondPage.setLayout(secondL);
secondPage.add(motherboard);
secondPage.add(mboardBox);
secondPage.add(ram);
secondPage.add(ramBox);
secondPage.add(numram);
secondPage.add(numRam);
secondPage.add(numssd);
secondPage.add(numSSD);
secondPage.add(numhdd);
secondPage.add(numHDD);
secondPage.add(odd);
secondPage.add(oddBox);
secondPage.add(numfan);
secondPage.add(numFan);
secondPage.add(nxt1);
secondPage.add(bck1);
GridLayout thirdL = new GridLayout(0,2);
thirdPage.setLayout(thirdL);
thirdPage.add(cpu);
thirdPage.add(cpuBox);
thirdPage.add(gpu);
thirdPage.add(gpuBox);
thirdPage.add(numGpu);
thirdPage.add(monitor);
thirdPage.add(monitorBox);
thirdPage.add(hours);
thirdPage.add(hoursUse);
thirdPage.add(nxt2);
thirdPage.add(bck2);
GridLayout resultL = new GridLayout(0,3);
results.setLayout(resultL);
results.add(outage);
results.add(outagePC);
results.add(watt);
results.add(peryear);
results.add(perYear);
results.add(kwatt);
results.add(costyear);
results.add(cost);
results.add(rm);
results.add(calc);
results.add(bck3);
results.add(exit2);
results.add(tips);
start.setText("Start");
start.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
//startActionPerformed(evt);
cl.show(contentPane,"2");
}
});
exit1.setText("Exit");
exit1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
// exit1ActionPerformed(evt);
System.exit(0);
}
});
exit2.setText("Exit");
exit2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
// exit2ActionPerformed(evt);
System.exit(0);
}
});
nxt1.setText("Next >>");
nxt1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
// nxt1ActionPerformed(evt);
cl.show(contentPane,"3");
ramNum = Integer.parseInt(numRam.getText());
ssdNum = Integer.parseInt(numSSD.getText());
hddNum = Integer.parseInt(numHDD.getText());
fanNum = Integer.parseInt(numFan.getText());
JComboBox cb1 = (JComboBox)evt.getSource();
String mboard = (String)cb1.getSelectedItem();
if("Average".equals(mboard)) {
motherboardP = 32;
}
if("High End".equals(mboard)) {
motherboardP = 60;
}
JComboBox cb2 = (JComboBox)evt.getSource();
String ramType = (String)cb2.getSelectedItem();
if("DDDR1".equals(ramType)) {
ramP = 5;
}
if("DDR2".equals(ramType)) {
ramP = 4;
}
if("DDR3".equals(ramType)) {
ramP = 2.5;
}
JComboBox cb3 = (JComboBox)evt.getSource();
String typeODD = (String)cb3.getSelectedItem();
if("DVD".equals(typeODD)) {
oddP = 22;
}
if("BluRay".equals(typeODD)) {
oddP = 27;
}
}
});
nxt2.setText("Next >>");
nxt2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
// nxt2ActionPerformed(evt);
cl.show(contentPane,"4");
gpuNum = Integer.parseInt(numGpu.getText());
hoursint = Integer.parseInt(hoursUse.getText());
JComboBox cb4 = (JComboBox)evt.getSource();
int inCPU = (Integer)cb4.getSelectedIndex();
switch(inCPU) {
case 0:
cpuP = 89;
break;
case 1:
cpuP = 119;
break;
case 2:
cpuP = 127;
break;
case 3:
cpuP = 125;
break;
case 4:
cpuP = 33;
break;
case 5:
cpuP = 98;
break;
}
JComboBox cb5 = (JComboBox)evt.getSource();
int nvGPU = (Integer)cb5.getSelectedIndex();
switch(nvGPU) {
case 0:
gpuP = 295;
break;
case 1:
gpuP = 100;
break;
case 2:
gpuP = 250;
break;
case 3:
gpuP = 150;
break;
case 4:
gpuP = 105;
break;
case 5:
gpuP = 275;
break;
}
JComboBox cb6 = (JComboBox)evt.getSource();
int mSize = (Integer)cb6.getSelectedIndex();
if(mSize == 0) {
monitorP = 20;
}
if(mSize == 1) {
monitorP = 28;
}
if(mSize == 2) {
monitorP = 50;
}
}
});
bck1.setText("<< Back");
bck1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
// bck1ActionPerformed(evt);
cl.show(contentPane,"1");
}
});
bck2.setText("<< Back");
bck2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
// bck2ActionPerformed(evt);
cl.show(contentPane,"2");
}
});
bck3.setText("<< Back");
bck3.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
// bck3ActionPerformed(evt);
cl.show(contentPane,"3");
}
});
tips.setText("Tips on saving energy");
tips.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
//tipsActionPerformed(evt);
try {
String url ="http://www.toptenreviews.com/computers/articles/10-computer-energy-saving-tips-go-green/";
Desktop dt = Desktop.getDesktop();
URI uri = new URI(url);
dt.browse(uri.resolve(uri));
}
catch (URISyntaxException | IOException e) {
JOptionPane.showMessageDialog(null, e.getMessage());
}
}
});
calc.setText("Calculate");
calc.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
// calcActionPerformed(evt);
gpuP *= gpuNum;
ramP *= ramNum;
hddP = hddNum * 5;
ssdP = ssdNum * 3;
fanP = fanNum * 4;
totalP = motherboardP + cpuP + gpuP + ramP +
hddP + ssdP + monitorP + fanP;
powerPerYear = totalP * hoursint * 365;
costRM = (float) ((powerPerYear / 1000) * tariff);
DecimalFormat df = new DecimalFormat("#.##");
df.format(costRM);
String outage = Double.toString(totalP);
String ppy = Double.toString(powerPerYear);
String price = Float.toString(costRM);
outagePC.setText(outage);
perYear.setText(ppy);
cost.setText(price);
}
});
mboardBox.setModel(new DefaultComboBoxModel(new String[] { "Average", "High End" }));
mboardBox.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
// mboardBoxActionPerformed(evt);
JComboBox cb = (JComboBox)evt.getSource();
String mboard = (String)cb.getSelectedItem();
if("Average".equals(mboard)) {
motherboardP = 32;
}
if("High End".equals(mboard)) {
motherboardP = 60;
}
}
});
ramBox.setModel(new DefaultComboBoxModel(new String[] { "DDR1", "DDR2", "DDR3" }));
ramBox.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
//ramBoxActionPerformed(evt);
JComboBox cb = (JComboBox)evt.getSource();
String ramType = (String)cb.getSelectedItem();
if("DDDR1".equals(ramType)) {
ramP = 5;
}
if("DDR2".equals(ramType)) {
ramP = 4;
}
if("DDR3".equals(ramType)) {
ramP = 2.5;
}
}
});
oddBox.setModel(new DefaultComboBoxModel(new String[] { "DVD", "BluRay" }));
oddBox.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
//oddBoxActionPerformed(evt);
JComboBox cb = (JComboBox)evt.getSource();
String typeODD = (String)cb.getSelectedItem();
if("DVD".equals(typeODD)) {
oddP = 22;
}
if("BluRay".equals(typeODD)) {
oddP = 27;
}
}
});
cpuBox.setModel(new DefaultComboBoxModel(new String[] { "intel Core i3", "intel Core i5", "intel Core i7", "AMD FX 4350", "AMD Sempron 64 3500", "AMD Athlon 64 FX-62" }));
cpuBox.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
//cpuBoxActionPerformed(evt);
JComboBox cb = (JComboBox)evt.getSource();
int inCPU = (Integer)cb.getSelectedIndex();
switch(inCPU) {
case 0:
cpuP = 89;
break;
case 1:
cpuP = 119;
break;
case 2:
cpuP = 127;
break;
case 3:
cpuP = 125;
break;
case 4:
cpuP = 33;
break;
case 5:
cpuP = 98;
break;
}
}
});
gpuBox.setModel(new DefaultComboBoxModel(new String[] { "NVidia GTX 500", "NVidia GTX 700", "NVidia GTX Titan", "AMD Radeon HD 2900", "AMD Radeon HD 3870", "AMD Radeon R9 Fury X" }));
gpuBox.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
//gpuBoxActionPerformed(evt);
JComboBox cb = (JComboBox)evt.getSource();
int nvGPU = (Integer)cb.getSelectedIndex();
switch(nvGPU) {
case 0:
gpuP = 295;
break;
case 1:
gpuP = 100;
break;
case 2:
gpuP = 250;
break;
case 3:
gpuP = 150;
break;
case 4:
gpuP = 105;
break;
case 5:
gpuP = 275;
break;
}
}
});
monitorBox.setModel(new DefaultComboBoxModel(new String[] { "17\"-19\"", "20\"-22\"", "24\"-30\"" }));
monitorBox.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
//monitorBoxActionPerformed(evt);
JComboBox cb = (JComboBox)evt.getSource();
int mSize = (Integer)cb.getSelectedIndex();
if(mSize == 0) {
monitorP = 20;
}
if(mSize == 1) {
monitorP = 28;
}
if(mSize == 2) {
monitorP = 50;
}
}
});
}
public static void go() {
JFrame frame = new JFrame();
frame.setVisible(true);
}
public static void main(String[] args) {
MainProject.go();
}
}
Where do I fix the code and how many bad Java programming practices have I implemented in my code?
回答1:
First...
You need to create an instance of CardLayout
BEFORE you apply it to the container and before add any components...
cl = new CardLayout();
contentPane.setLayout(cl);
Second...
You should be using the add(Component, Object) method
contentPane.add(mainPage, "1");
Third
public static void go() {
JFrame frame = new JFrame();
frame.setVisible(true);
}
Does nothing but creates an empty frame with nothing in it. It might be helpful to actually use MainProject
, since it extends from JFrame
Fourth...
Don't extend directly from JFrame
, you're not adding any new functionality to the class, it locks you into single use cases and it cause problems like the one you're having.
Instead, consider starting with a JPanel
instead...
public class MainProject extends JPanel {
(ps- This change may cause other compiler errors, which I'm not going to try and fix here)
Then simple create a new instance of a JFrame
and add your component to it...
public static void go() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new MainProject());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
Fifth
You might want to take a closer look at...
- Creating a GUI With JFC/Swing
- How to Use CardLayout
And...
- Why is my JLabel not showing up
- Listener Placement Adhering to the Traditional (non-mediator) MVC Pattern
for some more ideas and how you might better manage the CardLayout
You might also like to have a look at How to Use Tabbed Panes for an alternative
来源:https://stackoverflow.com/questions/36782236/using-cardlayout-for-multiple-jpanels-and-nothing-displays