[英]Why nothing happens after JButton is pressed
我有以下代碼-生成了除定義按下按鈕時應采取的操作的方法以外的所有Netbeans。 當我按下按鈕時,首先它不會恢復,並且在Netbeans IDE的標准輸出窗口中什么也沒有顯示。 怎么了?
import javax.swing.JFrame;
public class CodeCenter extends JFrame {
/**
* Creates new form CodeCenter
*/
public CodeCenter() {
initComponents();
}
/**
* 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() {
jScrollPane1 = new javax.swing.JScrollPane();
jTextArea1 = new javax.swing.JTextArea();
jButton1 = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jTextArea1.setColumns(20);
jTextArea1.setRows(5);
jScrollPane1.setViewportView(jTextArea1);
jButton1.setText("Run");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 711, Short.MAX_VALUE)
.addContainerGap())
.addGroup(layout.createSequentialGroup()
.addGap(288, 288, 288)
.addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 94, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addGap(17, 17, 17)
.addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 30, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 548, Short.MAX_VALUE)
.addContainerGap())
);
pack();
}// </editor-fold>
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
//writes each line of user code to seperate array place
//userCodeArray can then be passed into an enhanced for loop to act on each line individually
// May need to be moved into different class
String[] userCodeArray = getTextasArray();
System.out.println("Printing");
if(userCodeArray[0].equals("TEST")) {
System.out.println("Text read");
} else {
System.out.print("Text not read");
}
}
//Sets up Intrigued machine and the codecenter
public static void main(String args[]) {
//Not relevant to question
IntriguedMachine machine = new IntriguedMachine();
/* 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(CodeCenter.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(CodeCenter.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(CodeCenter.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(CodeCenter.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 CodeCenter().setVisible(true);
}
});
}
//Takes the user code, splits it into a single String for each line, puts each String into userCodeArray, and returns userCodeArray
//Not automatically-generated
public String[] getTextasArray() {
int lineCount = jTextArea1.getLineCount();
String[] userCodeArray = new String[lineCount];
for(int i = 0; i<lineCount; lineCount++){
String [] throwawayArray = jTextArea1.getText().split("//n");
userCodeArray = throwawayArray;
}
return userCodeArray;
} //End of getTextasArray;
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTextArea jTextArea1;
// End of variables declaration
}
好的,沒有冒犯,但您的getTextasArray
函數完全被劫持了。 毫無疑問,按下JButton
時什么也不發生的原因是因為輸入錯誤, for
循環是無限的。 讓我們看一下循環聲明,好嗎?
for(int i = 0; i<lineCount; lineCount++){
你看到什么問題了嗎? 看一下增量器部分。 不用增加i
,而是增加lineCount
,我認為這不是您想要的。 這意味着i
將永遠不會大於或等於lineCount
。 正如您親眼所見,您必須小心這些內容。 :)
但是,讓我們擺脫這個循環並以正確的方式進行操作。 我有點想知道您要通過使用for
循環來完成什么,但是有一種更簡單的方法。 像這樣編寫您的函數:
public String[] getTextasArray() {
return jTextArea1.getText().split("\n");
}
這將占用文本區域並用換行符將其分割。 注意,我使用字符串\\n
代替//n
。 使用//n
會將其拆分為文字“斜杠//n
”。 希望這會給您您想要的!
問題是這條線
String[] userCodeArray = getTextasArray();
特別
for(int i = 0; i < lineCount; lineCount++) {
String [] throwawayArray = jTextArea1.getText().split("//n");
userCodeArray = throwawayArray;
}
您不是在這里遞增i,而是lineCount。 這導致處理程序永不終止的無限循環。
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