[英]Jlabel will not update with setText from ActionListener?
我每次單擊“加載” Jbutton時都試圖更新一個空的Jlabel。 我已經在Jbutton中添加了一個動作偵聽器,但是由於某種原因,標簽只是不會更新,或者不會使用setText(String)方法顯示任何文本。
JLabel stupidLabel = new JLabel();
stupidLabel.setForeground(SystemColor.infoText);
stupidLabel.setFont(new Font("Arial", Font.PLAIN, 11));
stupidLabel.setBounds(71, 46, 167, 14);
panel.add(stupidLabel);'
JButton load = new JButton("Load");
load.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
stupidLabel.setText("Update please");
}
});
load.setFont(new Font("Arial", Font.PLAIN, 11));
load.setBounds(189, 92, 89, 22);
contentPane.add(load);
似乎不起作用。
似乎是什么問題? 有沒有辦法使標簽每秒鍾左右自動更新,從而完全消除對按鈕的需要?
對我來說很好...
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.SystemColor;
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.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
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 TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
JLabel stupidLabel = new JLabel(" ");
stupidLabel.setForeground(SystemColor.infoText);
stupidLabel.setFont(new Font("Arial", Font.PLAIN, 11));
add(stupidLabel, gbc);
JButton load = new JButton("Load");
load.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
stupidLabel.setText("Update please");
}
});
load.setFont(new Font("Arial", Font.PLAIN, 11));
add(load, gbc);
}
}
}
考慮提供一個可運行的示例來演示您的問題。 這不是代碼轉儲,而是您正在執行的操作的一個示例,突出顯示了您所遇到的問題。 這將減少混亂並改善響應
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