我应该使用GUI创建一个简单的乘法表,并且在大多数情况下,它正在做它应该做的事情。但我只是无法弄清楚它的底部,如果你点击一个特定的按钮,一个文本会说两个数字正在成倍增加和答案。
无论我点击什么按钮,它都只会告诉我输入的数字并将它们相乘。这是我的代码:
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JOptionPane;
public class MultiplicationTable {
int clickedCount;
int rowCount;
int colCount;
JFrame frame;
JPanel buttonPanel, countPanel;
JLabel countLabel;
private void createAndShowGui(){
rowCount = Integer.parseInt(JOptionPane
.showInputDialog("How many rows do you want your multiplication table to be? "));
colCount = Integer
.parseInt(JOptionPane
.showInputDialog("How many columns do you want your multiplication table to be? "));
frame = new JFrame ("Simple Multiplication Table");
frame.setLayout(new BorderLayout());
buttonPanel = new JPanel();
buttonPanel.setLayout(new GridLayout(rowCount, colCount));
countPanel = new JPanel();
countLabel = new JLabel("? x ? = ?");
for(int rowCounter = 1; rowCounter <= rowCount; rowCounter++)
for(int colCounter = 1; colCounter <= colCount; colCounter++){
final JButton j = new JButton(Integer.toString(rowCounter * colCounter));
j.addActionListener(new ActionListener(){
@Override
public void actionPerformed(ActionEvent event) {
for(int rc = 1; rc <= rowCount; rc++)
for(int cc = 1; cc <= colCount; cc++){
countLabel.setText(rc + " x " + cc + " = " + String.valueOf(rc * cc));
}
}
});
buttonPanel.add(j);
}
frame.add(buttonPanel, BorderLayout.NORTH);
countPanel.add(countLabel);
frame.add(countPanel, BorderLayout.SOUTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args){
MultiplicationTable c = new MultiplicationTable();
c.createAndShowGui();
}
}
答案 0 :(得分:2)
您当前的ActionListener
没有上下文,它不知道使用了哪两个值来生成您给出按钮的值。
你可以做的是创建一个ActionListener
,它取用于产生按钮文本的值,然后就可以相应地更新标签了。例如......
public class MultiplerActionListener implements ActionListener {
private int[] values;
private JLabel label;
public MultiplerActionListener(JLabel label, int... valuesToMultiple) {
values = valuesToMultiple;
this.label = label;
}
@Override
public void actionPerformed(ActionEvent event) {
int answer = 1;
StringBuilder sb = new StringBuilder(64);
for (int value : values) {
if (sb.length() > 0) {
sb.append(" x ");
}
sb.append(value);
answer *= value;
}
sb.append(" = ");
sb.append(answer);
label.setText(sb.toString());
}
}
然后,您只需在创建按钮
时应用它for(int rowCounter = 1; rowCounter <= rowCount; rowCounter++) {
for(int colCounter = 1; colCounter <= colCount; colCounter++){
final JButton j = new JButton(Integer.toString(rowCounter * colCounter));
j.addActionListener(new MultiplerActionListener(countLabel, rowCounter, colCounter));
buttonPanel.add(j);
}
}