读取一串字符串
我使用NetBeans IDE在java中创建了一个应用程序，但我遇到了问题。它不读取数组元素。这是代码：
private void buton1ActionPerformed(java.awt.event.ActionEvent evt) {
String[] toppings = new String[20];
toppings[0] = "";
toppings[1] = "";
toppings[2] = "";
toppings[3] = "";
int size = toppings.length;
for (int i=0; i<size; i++){
toppings[i]=textbox.getText();
label1.setText(toppings[0]);
label2.setText(toppings[1]);
label3.setText(toppings[2]);
label4.setText(toppings[3]);
}
}
每次按下按钮并为向量中的新元素添加新值时，我想将数组的每个元素放在标签（label1，label2，label3，label4）上。
此时，当我输入第一个元素的值时，它会将值设置为所有标签。
有人有想法吗？
2 个答案:
答案 0 :(得分：3)
你应该创建一个JLabel数组，然后在for循环中填写它们的文本：
private javax.swing.JLabel label[];
//write these lines within constructor or wherever you are creating your GUI
label = new javax.swing.JLabel[4];//
for (int i = 0 ; i < label.length ;i++)
label[i] = new javax.swing.jLabel();
然后更改buton1ActionPerformed
private void buton1ActionPerformed(java.awt.event.ActionEvent evt) {
String[] toppings = new String[20];
toppings[0] = "";
toppings[1] = "";
toppings[2] = "";
toppings[3] = "";
int size = toppings.length;
for (int i=0; i<size; i++){
toppings[i]=textbox.getText();
if (i < 4)
label[i].setText(toppings[i]);
}
}
编辑
在这里，我已经提供了代码的更新版本。只需运行它并告诉我它是否满足您的要求：
public class fereastra extends javax.swing.JFrame {
/**
* Creates new form fereastra
*/
public fereastra() {
initComponents();
buttonGroup1.add(singleplayer);
buttonGroup1.add(twoplayers);
buttonGroup1.add(threeplayers);
buttonGroup1.add(fourplayers);
casutatext.setVisible(true);
panel.setVisible(true);
text.setText("Wellcome! Please choose the number of players!");
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
label = new javax.swing.JLabel[4];//
for (int i = 0 ; i < label.length ;i++)
{label[i] = new javax.swing.JLabel();}
buttonGroup1 = new javax.swing.ButtonGroup();
casutatext = new javax.swing.JTextField();
text = new javax.swing.JLabel();
buton1 = new javax.swing.JButton();
jButton3 = new javax.swing.JButton();
panel = new javax.swing.JPanel();
fourplayers = new javax.swing.JRadioButton();
twoplayers = new javax.swing.JRadioButton();
threeplayers = new javax.swing.JRadioButton();
singleplayer = new javax.swing.JRadioButton();
test = new javax.swing.JLabel();
test2 = new javax.swing.JLabel();
test3 = new javax.swing.JLabel();
test4 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
casutatext.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
casutatextActionPerformed(evt);
}
});
text.setText("Text");
buton1.setText("OK");
buton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
buton1ActionPerformed(evt);
}
});
jButton3.setText("Cancel");
fourplayers.setText("4 players");
fourplayers.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
fourplayersActionPerformed(evt);
}
});
twoplayers.setText("2 players");
twoplayers.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
twoplayersActionPerformed(evt);
}
});
threeplayers.setText("3 players");
threeplayers.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
threeplayersActionPerformed(evt);
}
});
singleplayer.setText("Single player");
singleplayer.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
singleplayerActionPerformed(evt);
}
});
javax.swing.GroupLayout panelLayout = new javax.swing.GroupLayout(panel);
panel.setLayout(panelLayout);
panelLayout.setHorizontalGroup(
panelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(panelLayout.createSequentialGroup()
.addContainerGap()
.addComponent(singleplayer)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(twoplayers)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(threeplayers)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(fourplayers)
.addContainerGap())
);
panelLayout.setVerticalGroup(
panelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(panelLayout.createSequentialGroup()
.addContainerGap()
.addGroup(panelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(singleplayer)
.addComponent(twoplayers)
.addComponent(threeplayers)
.addComponent(fourplayers))
.addContainerGap())
);
test.setText("test");
test2.setText("jLabel1");
test3.setText("jLabel2");
test4.setText("jLabel3");
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(127, 127, 127)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(panel, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(casutatext, javax.swing.GroupLayout.PREFERRED_SIZE, 318, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(text, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)))
.addGroup(layout.createSequentialGroup()
.addGap(158, 158, 158)
.addComponent(label[0])
.addGap(36, 36, 36)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(buton1)
.addGap(35, 35, 35)
.addComponent(jButton3))
.addGroup(layout.createSequentialGroup()
.addComponent(label[1])
.addGap(32, 32, 32)
.addComponent(label[2])
.addGap(31, 31, 31)
.addComponent(label[3])))))
.addGap(93, 93, 93))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(61, 61, 61)
.addComponent(text)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(casutatext, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(panel, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(12, 12, 12)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(buton1)
.addComponent(jButton3))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 50, Short.MAX_VALUE)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(label[0])
.addComponent(label[1])
.addComponent(label[2])
.addComponent(label[3]))
.addGap(51, 51, 51))
);
pack();
}// </editor-fold>
private void casutatextActionPerformed(java.awt.event.ActionEvent evt) {
}
private void buton1ActionPerformed(java.awt.event.ActionEvent evt) {
String[] toppings = new String[20];
toppings[0] = "";
toppings[1] = "";
toppings[2] = "";
toppings[3] = "";
int size = toppings.length;
for (int i=0; i<size; i++){
toppings[i]=casutatext.getText();
if (i < 4)
{label[i].setText(toppings[i]);
}
}
}
private void singleplayerActionPerformed(java.awt.event.ActionEvent evt) {
numarjucatori=1;
}
private void twoplayersActionPerformed(java.awt.event.ActionEvent evt) {
numarjucatori=2;
}
private void threeplayersActionPerformed(java.awt.event.ActionEvent evt) {
numarjucatori=3;
}
private void fourplayersActionPerformed(java.awt.event.ActionEvent evt) {
numarjucatori=4;
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(fereastra.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(fereastra.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(fereastra.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(fereastra.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new fereastra().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton buton1;
private javax.swing.ButtonGroup buttonGroup1;
private javax.swing.JTextField casutatext;
private javax.swing.JRadioButton fourplayers;
private javax.swing.JButton jButton3;
private javax.swing.JPanel panel;
private javax.swing.JRadioButton singleplayer;
private javax.swing.JLabel test;
private javax.swing.JLabel test2;
private javax.swing.JLabel test3;
private javax.swing.JLabel test4;
private javax.swing.JLabel text;
private javax.swing.JRadioButton threeplayers;
private javax.swing.JRadioButton twoplayers;
// End of variables declaration
public int numarjucatori;
public String p1="", p2="", p3="", p4="";
private javax.swing.JLabel label[];
}
答案 1 :(得分：1)
我看到的第一个问题是你试图在for循环中设置标签文本，你应该在外面做它：
for(int i = 0; i < toppings.length; i++){
toppings[i] = textbox.getText();
}
label1.setText(toppings[0]);
// etc.
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