调用非静态类java

Question

我试图注意到，当我的java应用程序中发生特别的事情时，我试图让窗口闪烁（在mac和windows上）。然而，我是Java新手，对静态/非静态方法感到失望

不管我有多沮丧，我该如何称呼我的toggleVisible课程

我已经删除了不必要的代码：

public static void main(String args[]) {

Timer timer = new Timer();
        timer.scheduleAtFixedRate(new TimerTask() {
        @Override
        public void run() {
            checkAlerts();
        }
        }, 30000, 30000);
    }

public static Boolean checkAlerts(){

          if(count ==  0){
               JOptionPane.showMessageDialog(null, "No results");
           } else {
                toggleVisible();
                JOptionPane.showMessageDialog(null, "Some results back");
           }
    }

public void toggleVisible() {
      setVisible(!isVisible());
      if (isVisible()) {
        toFront();
        requestFocus();
        setAlwaysOnTop(true);
        try {
          //remember the last location of mouse
          final Point oldMouseLocation = MouseInfo.getPointerInfo().getLocation();

          //simulate a mouse click on title bar of window
          Robot robot = new Robot();
          robot.mouseMove(mainFrame.getX() + 100, mainFrame.getY() + 5);
          robot.mousePress(InputEvent.BUTTON1_DOWN_MASK);
          robot.mouseRelease(InputEvent.BUTTON1_DOWN_MASK);

          //move mouse to old location
          robot.mouseMove((int) oldMouseLocation.getX(), (int) oldMouseLocation.getY());
        } catch (Exception ex) {
          //just ignore exception, or you can handle it as you want
        } finally {
          setAlwaysOnTop(false);
        }
      }
    }

toggleVisible给了我一个错误：不能从静态上下文引用非静态方法toggleVisible（）

Answer 1

停止不必要地使用static关键字。相反，只需在main方法内创建类的一个对象，并调用一个方法，就可以利用这个方法来推进应用程序的流程

简单地说，考虑这个例子：

public class Example {

    private void performTask () {
        /*
         * Now start wriitng code from here.
         * Stop using main, for performing 
         * the tasks, which belongs to the 
         * application.
         */
    }

    public static void main ( String[] args ) {
        new Example ().performTask ();
    }
}

此外，你似乎正在处理Swing。出于这个原因，考虑javax.swing.Timer，^ ^ {CD4}}，因为前者假设将GUI相关的任务自动放在^ {< CD5> }，尽管后者的责任纯粹是与程序员有关。p>

下面是一个使用Swing的Timer类的小例子：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class LabelColourExample {

    private Timer timer;
    private JLabel label;
    private Color [] colours = { 
        Color.red,
        Color.blue,
        Color.green,
        Color.cyan,
        Color.yellow,
        Color.magenta,
        Color.black,
        Color.white
    };
    private int counter;

    private static final int GAP = 5;   

    private ActionListener timerActions = new ActionListener () {
        @Override
        public void actionPerformed ( ActionEvent ae ) {
            label.setForeground ( colours [ counter++ ] );
            counter %= colours.length;
        }
    };

    public LabelColourExample () {
        counter = 0;
    }

    private void displayGUI () {        
        JFrame frame = new JFrame ( "Label Colour Example" );
        frame.setDefaultCloseOperation ( JFrame.DISPOSE_ON_CLOSE );

        JPanel contentPane = new JPanel ();
        contentPane.setLayout ( new BorderLayout ( GAP, GAP ) );

        label = new JLabel ( "MyName", JLabel.CENTER );
        label.setOpaque ( true );
        contentPane.add ( label, BorderLayout.CENTER );

        JButton button = new JButton ( "Stop" );
        button.addActionListener ( new ActionListener () {
            @Override
            public void actionPerformed ( ActionEvent ae ) {
                JButton button = ( JButton ) ae.getSource ();
                if ( timer.isRunning () ) {
                    timer.stop ();
                    button.setText ( "Start" );
                } else {
                    timer.start ();
                    button.setText ( "Stop" );
                }
            }
        } );
        contentPane.add ( button, BorderLayout.PAGE_END );

        frame.setContentPane ( contentPane );
        frame.pack ();
        frame.setLocationByPlatform ( true );
        frame.setVisible ( true );

        timer = new Timer ( 1000, timerActions );
        timer.start ();
    }

    public static void main ( String[] args ) {
        Runnable runnable = new Runnable () {
            @Override
            public void run () {
                new LabelColourExample ().displayGUI ();
            }
        };
        EventQueue.invokeLater ( runnable );
    }
}