JTextFields在JPanel上的活动绘图之上,线程化问题
Mat*_*ijs 10 java swing multithreading rendering buffering
有没有人曾尝试使用Swing构建一个合适的多缓冲渲染环境,在此环境中可以添加Swing用户界面元素？
在这种情况下,我有一个动画红色矩形绘制在背景上.背景不需要每帧更新,因此我将其渲染到BufferedImage上,并仅重绘清除矩形的先前位置所需的部分.请参见下面的完整代码,这扩展了以前的线程通过@trashgod给出的例子,在这里.
到现在为止还挺好; 流畅的动画,低CPU使用率,无闪烁.
然后我将JTextField添加到Jpanel(通过单击屏幕上的任何位置),并通过在文本框内单击来关注它.现在,清除矩形的先前位置会在每个光标闪烁时失败,请参见下图.
我很好奇是否有人知道为什么会发生这种情况(Swing不是线程安全的？图像是异步绘制的？)以及寻找可能解决方案的方向.
这是在Mac OS 10.5,Java 1.6上
JPanel重绘失败了http://www.arttech.nl/javaredrawerror.png
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.Insets;
import java.awt.Rectangle;
import java.awt.Transparency;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ComponentEvent;
import java.awt.event.ComponentListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.image.BufferedImage;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.Timer;
public class NewTest extends JPanel implements
MouseListener,
ActionListener,
ComponentListener,
Runnable
{
JFrame f;
Insets insets;
private Timer t = new Timer(20, this);
BufferedImage buffer1;
boolean repaintBuffer1 = true;
int initWidth = 640;
int initHeight = 480;
Rectangle rect;
public static void main(String[] args) {
EventQueue.invokeLater(new NewTest());
}
@Override
public void run() {
f = new JFrame("NewTest");
f.addComponentListener(this);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(this);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
createBuffers();
insets = f.getInsets();
t.start();
}
public NewTest() {
super(true);
this.setPreferredSize(new Dimension(initWidth, initHeight));
this.setLayout(null);
this.addMouseListener(this);
}
void createBuffers() {
int width = this.getWidth();
int height = this.getHeight();
GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
GraphicsDevice gs = ge.getDefaultScreenDevice();
GraphicsConfiguration gc = gs.getDefaultConfiguration();
buffer1 = gc.createCompatibleImage(width, height, Transparency.OPAQUE);
repaintBuffer1 = true;
}
@Override
protected void paintComponent(Graphics g) {
int width = this.getWidth();
int height = this.getHeight();
if (repaintBuffer1) {
Graphics g1 = buffer1.getGraphics();
g1.clearRect(0, 0, width, height);
g1.setColor(Color.green);
g1.drawRect(0, 0, width - 1, height - 1);
g.drawImage(buffer1, 0, 0, null);
repaintBuffer1 = false;
}
double time = 2* Math.PI * (System.currentTimeMillis() % 5000) / 5000.;
g.setColor(Color.RED);
if (rect != null) {
g.drawImage(buffer1, rect.x, rect.y, rect.x + rect.width, rect.y + rect.height, rect.x, rect.y, rect.x + rect.width, rect.y + rect.height, this);
}
rect = new Rectangle((int)(Math.sin(time) * width/3 + width/2 - 20), (int)(Math.cos(time) * height/3 + height/2) - 20, 40, 40);
g.fillRect(rect.x, rect.y, rect.width, rect.height);
}
@Override
public void actionPerformed(ActionEvent e) {
this.repaint();
}
@Override
public void componentHidden(ComponentEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void componentMoved(ComponentEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void componentResized(ComponentEvent e) {
int width = e.getComponent().getWidth() - (insets.left + insets.right);
int height = e.getComponent().getHeight() - (insets.top + insets.bottom);
this.setSize(width, height);
createBuffers();
}
@Override
public void componentShown(ComponentEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void mouseClicked(MouseEvent e) {
JTextField field = new JTextField("test");
field.setBounds(new Rectangle(e.getX(), e.getY(), 100, 20));
this.add(field);
repaintBuffer1 = true;
}
@Override
public void mouseEntered(MouseEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void mouseExited(MouseEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void mousePressed(MouseEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void mouseReleased(MouseEvent arg0) {
// TODO Auto-generated method stub
}
}
tra*_*god 18
NewTest延伸JPanel; 但是因为你没有在每次调用时绘制每个像素paintComponent(),你需要调用超类的方法并删除旧的绘图:
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
int width = this.getWidth();
int height = this.getHeight();
g.setColor(Color.black);
g.fillRect(0, 0, width, height);
...
}
附录:如您所知,在构造函数中设置背景颜色可以排除填充面板的需要paintComponent(),同时super.paintComponent()允许文本字段正常运行.如您所见,建议的解决方法很脆弱.相反,简化代码并根据需要进行优化.例如,您可能不需要插入内容,额外缓冲区和组件侦听器的复杂性.
附录2:请注意,super.paintComponent()调用UI委托的update()方法,"使用其背景颜色填充指定的组件(如果其opaque属性为true)." 你可以setOpaque(false)用来排除这个.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsEnvironment;
import java.awt.Rectangle;
import java.awt.Transparency;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.Timer;
/** @see http://stackoverflow.com/questions/3256941 */
public class AnimationTest extends JPanel implements ActionListener {
private static final int WIDE = 640;
private static final int HIGH = 480;
private static final int RADIUS = 25;
private static final int FRAMES = 24;
private final Timer timer = new Timer(20, this);
private final Rectangle rect = new Rectangle();
private BufferedImage background;
private int index;
private long totalTime;
private long averageTime;
private int frameCount;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
new AnimationTest().create();
}
});
}
private void create() {
JFrame f = new JFrame("AnimationTest");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(this);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
timer.start();
}
public AnimationTest() {
super(true);
this.setOpaque(false);
this.setPreferredSize(new Dimension(WIDE, HIGH));
this.addMouseListener(new MouseHandler());
this.addComponentListener(new ComponentHandler());
}
@Override
protected void paintComponent(Graphics g) {
long start = System.nanoTime();
super.paintComponent(g);
int w = this.getWidth();
int h = this.getHeight();
g.drawImage(background, 0, 0, this);
double theta = 2 * Math.PI * index++ / 64;
g.setColor(Color.blue);
rect.setRect(
(int) (Math.sin(theta) * w / 3 + w / 2 - RADIUS),
(int) (Math.cos(theta) * h / 3 + h / 2 - RADIUS),
2 * RADIUS, 2 * RADIUS);
g.fillOval(rect.x, rect.y, rect.width, rect.height);
g.setColor(Color.white);
if (frameCount == FRAMES) {
averageTime = totalTime / FRAMES;
totalTime = 0; frameCount = 0;
} else {
totalTime += System.nanoTime() - start;
frameCount++;
}
String s = String.format("%1$5.3f", averageTime / 1000000d);
g.drawString(s, 5, 16);
}
@Override
public void actionPerformed(ActionEvent e) {
this.repaint();
}
private class MouseHandler extends MouseAdapter {
@Override
public void mousePressed(MouseEvent e) {
super.mousePressed(e);
JTextField field = new JTextField("test");
Dimension d = field.getPreferredSize();
field.setBounds(e.getX(), e.getY(), d.width, d.height);
add(field);
}
}
private class ComponentHandler extends ComponentAdapter {
private final GraphicsEnvironment ge =
GraphicsEnvironment.getLocalGraphicsEnvironment();
private final GraphicsConfiguration gc =
ge.getDefaultScreenDevice().getDefaultConfiguration();
private final Random r = new Random();
@Override
public void componentResized(ComponentEvent e) {
super.componentResized(e);
int w = getWidth();
int h = getHeight();
background = gc.createCompatibleImage(w, h, Transparency.OPAQUE);
Graphics2D g = background.createGraphics();
g.clearRect(0, 0, w, h);
g.setColor(Color.green.darker());
for (int i = 0; i < 128; i++) {
g.drawLine(w / 2, h / 2, r.nextInt(w), r.nextInt(h));
}
g.dispose();
System.out.println("Resized to " + w + " x " + h);
}
}
}