Question

我正在制作一个Simon说的程序，我需要按钮在生成随机模式时闪烁，以便用户知道要输入的内容。我的问题是我不能让我的按钮（JButtons是图像）闪烁，我的逻辑是两个按钮在彼此的顶部，一个可见，而不是然后切换按钮可见性，等待一秒然后再改回来。我试过使用Thread.sleep（），wait（），甚至繁忙的循环等待，但没有一个工作。我被告知摇摆计时器是我最好的选择，这就是我想要使用的。此外，我希望按钮在单击开始按钮后开始闪烁。

let file = event.target.files[0];
let data = new FormData();
data.append("file", file, file.name);
let _file = data.get("file");

这是第一个保持简单的按钮的代码。

Answer 1

您似乎试图在自己的侦听器中重新启动Timer，这是您不应该做的事情。了解该侦听器中的actionPerformed方法将在您的代码中每500毫秒重复调用一次，并且无需尝试重新启动＆＃34;计时器，因为它已经运行。而是在actionPerformed方法内部，你应该有代码来决定哪个按钮应该改变图标/状态，以及放入哪个图标。

例如，请考虑以下代码。它假设有两个图标，一个名为greenIcon，一个名为darkGreenIcon，我想每200毫秒交换这些图标。在我的计时器动作中，我会通过调用按钮上的getIcon()来检查按钮中当前显示的图标。如果它是greenIcon，我会通过setIcon(...)在按钮中放置一个darkGreenIcon，反之亦然，如果它是一个darkGreenIcon，我会放入一个greenIcon。代码看起来像：

    @Override
    public void actionPerformed(ActionEvent e) {
        // get icon from button
        Icon icon = greenButton.getIcon();

        // check if it's the green icon
        if (icon == greenIcon) {
            icon = darkGreenIcon;  // if so, make it the dark green icon
        } else {
            icon = greenIcon;  // if not, make it the green icon
        }
        greenButton.setIcon(icon);  // stuff it back into the button
    }

例如，一个可运行的程序：

import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import javax.swing.*;

@SuppressWarnings("serial")
public class FlashingButton extends JPanel {
    private static final String START = "Start";
    private static final String STOP = "Stop";
    private static final int TIMER_DELAY = 200; // millisecond delay
    private static final int BI_WIDTH = 400;
    private Icon greenIcon;
    private Icon darkGreenIcon;
    private JButton greenButton = new JButton();
    private JButton startButton = new JButton(new StartAction(START));
    private Timer timer = new Timer(TIMER_DELAY, new TimerListener());

    public FlashingButton() {
        greenIcon = createMyIcon(Color.GREEN);
        darkGreenIcon = createMyIcon(Color.GREEN.darker());
        greenButton.setIcon(greenIcon);
        setBorder(BorderFactory.createEmptyBorder(40, 40, 40, 40));
        setLayout(new BorderLayout(20, 20));

        add(greenButton, BorderLayout.CENTER);
        add(startButton, BorderLayout.PAGE_END);
    }

    // Ignore this code. It simply is present to create image icons 
    // without having to use an actual image. This way you can run this code without an image
    private Icon createMyIcon(Color color) {
        BufferedImage img = new BufferedImage(BI_WIDTH, BI_WIDTH, BufferedImage.TYPE_INT_ARGB);
        Graphics2D g2 = img.createGraphics();
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        g2.setColor(color);
        g2.fillOval(5, 5, BI_WIDTH - 10, BI_WIDTH - 10);
        g2.setStroke(new BasicStroke(10f));
        g2.setColor(Color.LIGHT_GRAY);
        g2.drawOval(5, 5, BI_WIDTH - 10, BI_WIDTH - 10);
        g2.dispose();
        return new ImageIcon(img);
    }

    private class TimerListener implements ActionListener {

        @Override
        public void actionPerformed(ActionEvent e) {
            // get icon from button
            Icon icon = greenButton.getIcon();

            // check if it's the green icon
            if (icon == greenIcon) {
                icon = darkGreenIcon;  // if so, make it the dark green icon
            } else {
                icon = greenIcon;  // if not, make it the green icon
            }
            greenButton.setIcon(icon);  // stuff it back into the button
        }
    }

    // this is my startButton's Action.
    // an Action is like an "ActionListener on steroids"
    private class StartAction extends AbstractAction {
        public StartAction(String name) {
            super(name);  // the text that appears in the button
            putValue(MNEMONIC_KEY, (int) name.charAt(0));  // the alt-key mnemonic
        }

        @Override
        public void actionPerformed(ActionEvent e) {
            if (timer.isRunning()) {  // if the timer is currently running
                timer.stop();    // stop the Timer
                greenButton.setIcon(greenIcon);  // set the icon back to the defaut green icon
                putValue(NAME, START);  // change the button's text to "Start"
            } else {  // otherwise the Timer's not running
                timer.start();  // Start it
                putValue(NAME, STOP);  // change this button's text to "Stop"
            }
        }
    }

    private static void createAndShowGui() {
        JFrame frame = new JFrame("Flashing Button");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(new FlashingButton());
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> createAndShowGui());
    }
}

西蒙的闪烁按钮说

1 个答案: