[英]Marquee effect in Java Swing
如何在Java Swing中實現字幕效果
這是使用javax.swing.Timer
的示例。
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Timer;
/** @see http://stackoverflow.com/questions/3617326 */
public class MarqueeTest {
private void display() {
JFrame f = new JFrame("MarqueeTest");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
String s = "Tomorrow, and tomorrow, and tomorrow, "
+ "creeps in this petty pace from day to day, "
+ "to the last syllable of recorded time; ... "
+ "It is a tale told by an idiot, full of "
+ "sound and fury signifying nothing.";
MarqueePanel mp = new MarqueePanel(s, 32);
f.add(mp);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
mp.start();
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
new MarqueeTest().display();
}
});
}
}
/** Side-scroll n characters of s. */
class MarqueePanel extends JPanel implements ActionListener {
private static final int RATE = 12;
private final Timer timer = new Timer(1000 / RATE, this);
private final JLabel label = new JLabel();
private final String s;
private final int n;
private int index;
public MarqueePanel(String s, int n) {
if (s == null || n < 1) {
throw new IllegalArgumentException("Null string or n < 1");
}
StringBuilder sb = new StringBuilder(n);
for (int i = 0; i < n; i++) {
sb.append(' ');
}
this.s = sb + s + sb;
this.n = n;
label.setFont(new Font("Serif", Font.ITALIC, 36));
label.setText(sb.toString());
this.add(label);
}
public void start() {
timer.start();
}
public void stop() {
timer.stop();
}
@Override
public void actionPerformed(ActionEvent e) {
index++;
if (index > s.length() - n) {
index = 0;
}
label.setText(s.substring(index, index + n));
}
}
我知道這是一個較晚的答案,但我剛剛看到另一個有關選取框已關閉的問題,因為它被認為是該答案的重復。
因此,我想我要添加我的建議,該建議所采用的方法與此處建議的其他答案不同。
MarqueePanel滾動面板上的組件而不僅僅是文本。 因此,這使您可以充分利用任何Swing組件。 通過添加帶有文本的JLabel可以使用簡單的字幕。 選框可能會使用帶有HTML的JLabel,因此您可以為文本使用不同的字體和顏色。 您甚至可以在圖像中添加第二個組件。
我剛剛在Google上搜索了它,並找到了此鏈接 。 我運行了代碼,它似乎可以滿足您的要求。
基本的答案是將文本/圖形繪制到位圖中,然后實現一個將位圖偏移量繪制為一定數量的組件。 通常,字幕/行情指示器向左滾動,因此偏移量增加,這意味着位圖在-offset處繪制。 您的組件運行一個計時器,該計時器定期觸發,增加偏移量並使自身無效,以便重新繪制。
諸如包裝之類的東西要處理起來稍微復雜一些,但相當簡單。 如果偏移量超過位圖寬度,則將其重置為0。如果偏移量+組件寬度>位圖寬度,則從位圖的開頭開始繪制其余分量。
不錯的行情收錄器的關鍵是使滾動盡可能平滑和無閃爍。 因此,可能有必要考慮對結果進行雙重緩沖,首先將滾動位繪制為位圖,然后一次性渲染而不是直接繪制到屏幕中。
這是我拼湊的一些代碼,可以幫助您入門。 我通常會使用ActionListener代碼,並將其放在某種MarqueeController
類中,以使該邏輯與面板分離,但這是組織MVC架構的另一個問題,在這樣簡單的類中,它可能並不那么重要。
還有各種動畫庫可以幫助您完成此任務,但是我通常不希望將庫包含在項目中只是為了解決這樣的問題。
public class MarqueePanel extends JPanel { private JLabel textLabel; private int panelLocation; private ActionListener taskPerformer; private boolean isRunning = false; public static final int FRAMES_PER_SECOND = 24; public static final int MOVEMENT_PER_FRAME = 5; /** * Class constructor creates a marquee panel. */ public MarqueePanel() { this.setLayout(null); this.textLabel = new JLabel("Scrolling Text Here"); this.panelLocation = 0; this.taskPerformer = new ActionListener() { public void actionPerformed(ActionEvent evt) { MarqueePanel.this.tickAnimation(); } } } /** * Starts the animation. */ public void start() { this.isRunning = true; this.tickAnimation(); } /** * Stops the animation. */ public void stop() { this.isRunning = false; } /** * Moves the label one frame to the left. If it's out of display range, move it back * to the right, out of display range. */ private void tickAnimation() { this.panelLocation -= MarqueePanel.MOVEMENT_PER_FRAME; if (this.panelLocation < this.textLabel.getWidth()) this.panelLocaton = this.getWidth(); this.textLabel.setLocation(this.panelLocation, 0); this.repaint(); if (this.isRunning) { Timer t = new Timer(1000 / MarqueePanel.FRAMES_PER_SECOND, this.taskPerformer); t.setRepeats(false); t.start(); } } }
將JLabel添加到框架或面板。
ScrollText s= new ScrollText("ello Everyone.");
jLabel3.add(s);
public class ScrollText extends JComponent {
private BufferedImage image;
private Dimension imageSize;
private volatile int currOffset;
private Thread internalThread;
private volatile boolean noStopRequested;
public ScrollText(String text) {
currOffset = 0;
buildImage(text);
setMinimumSize(imageSize);
setPreferredSize(imageSize);
setMaximumSize(imageSize);
setSize(imageSize);
noStopRequested = true;
Runnable r = new Runnable() {
public void run() {
try {
runWork();
} catch (Exception x) {
x.printStackTrace();
}
}
};
internalThread = new Thread(r, "ScrollText");
internalThread.start();
}
private void buildImage(String text) {
RenderingHints renderHints = new RenderingHints(
RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
renderHints.put(RenderingHints.KEY_RENDERING,
RenderingHints.VALUE_RENDER_QUALITY);
BufferedImage scratchImage = new BufferedImage(1, 1,
BufferedImage.TYPE_INT_RGB);
Graphics2D scratchG2 = scratchImage.createGraphics();
scratchG2.setRenderingHints(renderHints);
Font font = new Font("Serif", Font.BOLD | Font.ITALIC, 24);
FontRenderContext frc = scratchG2.getFontRenderContext();
TextLayout tl = new TextLayout(text, font, frc);
Rectangle2D textBounds = tl.getBounds();
int textWidth = (int) Math.ceil(textBounds.getWidth());
int textHeight = (int) Math.ceil(textBounds.getHeight());
int horizontalPad = 600;
int verticalPad = 10;
imageSize = new Dimension(textWidth + horizontalPad, textHeight
+ verticalPad);
image = new BufferedImage(imageSize.width, imageSize.height,
BufferedImage.TYPE_INT_RGB);
Graphics2D g2 = image.createGraphics();
g2.setRenderingHints(renderHints);
int baselineOffset = (verticalPad / 2) - ((int) textBounds.getY());
g2.setColor(Color.BLACK);
g2.fillRect(0, 0, imageSize.width, imageSize.height);
g2.setColor(Color.GREEN);
tl.draw(g2, 0, baselineOffset);
// Free-up resources right away, but keep "image" for
// animation.
scratchG2.dispose();
scratchImage.flush();
g2.dispose();
}
public void paint(Graphics g) {
// Make sure to clip the edges, regardless of curr size
g.setClip(0, 0, imageSize.width, imageSize.height);
int localOffset = currOffset; // in case it changes
g.drawImage(image, -localOffset, 0, this);
g.drawImage(image, imageSize.width - localOffset, 0, this);
// draw outline
g.setColor(Color.black);
g.drawRect(0, 0, imageSize.width - 1, imageSize.height - 1);
}
private void runWork() {
while (noStopRequested) {
try {
Thread.sleep(10); // 10 frames per second
// adjust the scroll position
currOffset = (currOffset + 1) % imageSize.width;
// signal the event thread to call paint()
repaint();
} catch (InterruptedException x) {
Thread.currentThread().interrupt();
}
}
}
public void stopRequest() {
noStopRequested = false;
internalThread.interrupt();
}
public boolean isAlive() {
return internalThread.isAlive();
}
}
這應該是@camickr MarqueePanel的改進。 請參閱上面。
將鼠標事件映射到添加到MarqueePanel的特定組件
重寫MarqueePanel的add(Component comp)
以指示組件的所有鼠標事件
這里的問題是如何處理從單個組件觸發的MouseEvent。 我的方法是從添加的組件中刪除鼠標偵聽器,然后讓MarqueePanel將事件重定向到正確的組件。
就我而言,這些組件應該是鏈接。
@Override
public Component add(Component comp) {
comp = super.add(comp);
if(comp instanceof MouseListener)
comp.removeMouseListener((MouseListener)comp);
comp.addMouseListener(this);
return comp;
}
然后將組件x映射到MarqueePanel x,最后映射到正確的組件
@Override
public void mouseClicked(MouseEvent e)
{
Component source = (Component)e.getSource();
int x = source.getX() + e.getX();
int y = source.getY();
MarqueePanel2 marqueePanel = (MarqueePanel2) ((JComponent)e.getSource()).getParent();
double x2 = marqueePanel.getWidth();
double x1 = Math.abs(marqueePanel.scrollOffset);
if(x >= x1 && x <= x2)
{
System.out.println("Bang " + x1);
Component componentAt = getComponentAt(x+marqueePanel.scrollOffset, y);
if(comp instanceof MouseListener)
((MouseListener) componentAt).mouseClicked(e);
System.out.println(componentAt.getName());
}
else
{
return;
}
//System.out.println(x);
}
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