我编写了这个简单的程序，它显示按键，绘制短语“Hello World”，其中一个光标移动（单击时带有轨迹模式），并且还循环选择“Hello World”的颜色，当鼠标滚轮滚动。但是这样做有一个问题：当鼠标滚轮滚动时，整个窗口变为空白（显示从您第一次使组件可见时的默认灰色），然后将随着颜色的变化而重新绘制（仅对“Hello World”似乎不需要重绘整个框架。
出现空白的时间似乎与滚动鼠标滚轮的力相关，如果我轻轻滚动，只有很小的一瞬间没有显示所有内容，但是非常用力滚动会使窗口变为空白2-3 秒。
我试过双缓冲——认为这可能是某种屏幕闪烁——但它没有改变，我不知道是什么导致了这种奇怪的效果。就好像在 Wheel 运动事件发生时正在加载帧图像。（有没有办法立即退出轮子事件以减少加载时间？（这只是我对可能解决方案的猜测））。
代码如下。任何想法将不胜感激。
package keymouse;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferStrategy;
import java.util.LinkedList;
import javax.swing.JFrame;
public class KeyMouse implements KeyListener,
MouseMotionListener, MouseListener, MouseWheelListener, Runnable {
boolean trailMode = false;
boolean exists = false;
display window;
LinkedList wordList;
LinkedList trailList;
LinkedList colorList;
Point mousePoint;
int TRAIL_SIZE = 10;
boolean init = true;
int FONT_SIZE = 32;
int mouseY;
int mouseX;
int y;
int colorCount = 0;
public static void main(String[] args) {
KeyMouse k = new KeyMouse();
k.run();
}
public KeyMouse() {
window = new display();
window.addKeyListener(this);
window.addMouseMotionListener(this);
window.addMouseListener(this);
window.addMouseWheelListener(this);
window.setBackground(Color.WHITE);
window.setForeground(Color.BLACK);
wordList = new LinkedList();
trailList = new LinkedList();
colorList = new LinkedList();
colorList.add(Color.BLACK);
colorList.add(Color.BLUE);
colorList.add(Color.YELLOW);
colorList.add(Color.GREEN);
colorList.add(Color.PINK);
}
@Override
public void keyTyped(KeyEvent e) {
// do nothing
}
@Override
public void keyPressed(KeyEvent e) {
int keyCode;
if (e.getKeyCode() == KeyEvent.VK_ESCAPE) {
stop();
}
keyCode = e.getKeyCode();
addMessage("Pressed:" + e.getKeyText(keyCode));
}
@Override
public void keyReleased(KeyEvent e) {
//do nothing
}
@Override
public void mouseDragged(MouseEvent e) {
Point p = new Point(e.getX(), e.getY());
addLocation(p);
}
@Override
public void mouseMoved(MouseEvent e) {
Point p = new Point(e.getX(), e.getY());
addLocation(p);
}
@Override
public void mouseClicked(MouseEvent e) {
}
@Override
public void mousePressed(MouseEvent e) {
trailMode = true;
}
@Override
public void mouseReleased(MouseEvent e) {
trailMode = false;
}
@Override
public void mouseEntered(MouseEvent e) {
//do nothing
}
@Override
public void mouseExited(MouseEvent e) {
//do nothing
}
@Override
public void mouseWheelMoved(MouseWheelEvent e) {
System.out.println(e.getWheelRotation());
colorCount++;
if (colorCount > 4) {
colorCount = 0;
}
window.setForeground((Color) colorList.get(colorCount));
}
@Override
public void run() {
window.createBufferStrategy(2);
BufferStrategy strategy = window.getBufferStrategy();
while (true) {
draw(strategy.getDrawGraphics());
strategy.show();
try {
Thread.sleep(20);
} catch (Exception ex) {
}
}
}
public void draw(Graphics g) {
//draw background
g.setColor(window.getBackground());
g.fillRect(0, 0, window.getWidth(), window.getHeight());
//draw Text
g.setColor(window.getForeground());
g.setFont(new Font("sansserif", Font.BOLD, 32));
int count = trailList.size();
if (trailList.size() > 1 && trailMode == false) {
count = 1;
}
if (exists == true) {
for (int i = 0; i < count; i++) {
Point p = (Point) trailList.get(i);
g.drawString("Hello World", p.x, p.y);
}
}
g.setColor(Color.BLACK);
y = 56;
for (int i = 0; i < wordList.size(); i++) {
String word = (String) wordList.get(i);
g.drawString((String) wordList.get(i), 100, y);
y += 32;
}
}
public void addMessage(String message) {
if (y >= window.getHeight()) {
wordList.remove(0);
}
wordList.add(message);
}
public void addLocation(Point h) {
exists = true;
trailList.addFirst(h);
if (trailList.size() > TRAIL_SIZE) {
trailList.removeLast();
}
}
public void printMessages() {
for (int i = 0; i < wordList.size(); i++) {
System.out.println(wordList.get(i));
}
}
private void stop() {
System.exit(0);
}
