在 JTabbedPane 上触发 stateChanged 事件

Question

我有带有淡入淡出动画的 JTabbedPane，这是在用户单击选项卡时执行的。为了处理动画，我重写了stateChanged 方法。

public class AnimatedJTabbedPane extends JTabbedPane implements ChangeListener, TimingTarget{

/**
 * 
 */
private static final long serialVersionUID = 1L;
protected BufferedImage previousTabImage;
protected BufferedImage bufferImage;
protected BufferedImage nextTabImage;
protected boolean animationStarted = false;
protected boolean paintPreviousImage = false;
protected boolean leftToRightIndex = false;
protected float fraction = 0.0f;
protected Animator animator;
protected int previousTabIndex = -1;

public AnimatedJTabbedPane(int tabPlacement) {
    super(tabPlacement);

    this.animator = new Animator(300, this);
    this.animator.setAcceleration(0.1f);
    this.animator.setDeceleration(0.8f);
    this.addChangeListener(this);
}

public void stateChanged(ChangeEvent e) {

    if(this.previousTabIndex != this.getSelectedIndex()){
        if(this.previousTabIndex == -1){
            this.previousTabIndex = this.getSelectedIndex();
        }
        else{
            this.paintPreviousImage = true; 
            boolean interrupted = false;
            if(this.animator.isRunning()){
                this.animator.stop();
                interrupted= true;
            }

            Component previousComponent = this.getComponentAt(this.previousTabIndex);

            this.previousTabImage = this.getGraphicsConfiguration().createCompatibleImage(
                    previousComponent.getWidth(), previousComponent.getHeight(), Transparency.TRANSLUCENT);

            previousComponent.paint(this.previousTabImage.getGraphics());

            Component nextComponent = this.getComponentAt(this.getSelectedIndex());
            this.nextTabImage = this.getGraphicsConfiguration().createCompatibleImage(
                    previousComponent.getWidth(), previousComponent.getHeight(), Transparency.TRANSLUCENT);

            nextComponent.paint(this.nextTabImage.getGraphics());

            if(this.previousTabIndex < this.getSelectedIndex()){
                this.leftToRightIndex = true;
            }
            else{
                this.leftToRightIndex = false;
            }

            this.previousTabIndex = this.getSelectedIndex();
            if(interrupted){
                this.animator.setStartFraction(1-this.fraction);
            }
            else{
                this.animator.setStartFraction(0);
            }
            this.animationStarted = true;
            this.animator.start();
        }
    }
}


@Override
public void paintChildren(Graphics g){
    if(this.getComponentCount() != 0){
        Rectangle childrenPosition = this.getComponentAt(0).getBounds();

        if(this.bufferImage == null || 
                this.bufferImage.getWidth() != this.getWidth() ||
                this.bufferImage.getHeight() != this.getHeight()){
            this.bufferImage = new BufferedImage(
                    this.getWidth(), 
                    this.getHeight(), 
                    BufferedImage.TYPE_INT_ARGB);
        }

        if(this.animationStarted){
            if(this.paintPreviousImage){
                g.drawImage(this.bufferImage, 0, 0, null);
                this.paintPreviousImage = false;
            }
            else{
                Graphics2D g2d = (Graphics2D)this.bufferImage.createGraphics(); 
                int x = (int)childrenPosition.getX();
                int y = (int)childrenPosition.getY();

                this.performFadeAnimation(g2d, x, y);

                g.drawImage(this.bufferImage, 0, 0, null);
                g2d.dispose();
            }
            g.dispose();
        }
        else{
            Graphics2D g2d = (Graphics2D)this.bufferImage.createGraphics(); 

            super.paintChildren(g2d);
            g.drawImage(this.bufferImage, 0, 0, null);
            g2d.dispose();
            g.dispose();
        }
    }
    else{
        super.paintChildren(g);
    }
}


protected void performFadeAnimation(Graphics2D g2d, final double x, final double y){
    g2d.drawImage(this.previousTabImage, (int)x, (int)y, null);

    AlphaComposite composite = 
            AlphaComposite.getInstance(AlphaComposite.SRC_OVER, this.fraction);
    g2d.setComposite(composite);

    g2d.drawImage(this.nextTabImage,  (int)x, (int)y, null);
}

@Override
public void begin() {
    // TODO Auto-generated method stub
}

@Override
public void end() {
    this.animationStarted = false;
    this.repaint();
    this.nextTabImage.flush();
    this.nextTabImage = null;
    this.previousTabImage.flush();
    this.previousTabImage = null;
}

@Override
public void repeat() {
    // TODO Auto-generated method stub
}

@Override
public void timingEvent(float fraction) {
    this.fraction = fraction;
    this.repaint();
}

}

当用户手动单击选项卡时，这非常有用。 stateChanged 事件被调用，标签随着动画的变化而变化。

我需要从代码中更改选定的选项卡，所以我使用setSelectedIndex(int) 方法。

public void setSelectedTab(int tab){
    animatedTabbedPane.setSelectedIndex(tab);
}

但现在标签在setSelectedIndex 结束后立即更改 - 没有动画，然后调用 stateChanged 方法，因此标签切换回之前选择的标签并（正确）执行我的动画。

所以标签改变了两次，第一次在setSelectedIndex 之后没有动画，第二次在AnimatedJTabbedPane 中的stateChanged 之后。

我需要类似的东西：

 animatedTabbedPane.firePropertyChange("stateChanged", old, new);

我只想使用stateChanged 方法更改选项卡，所以我可以不使用默认的setSelectedIndex 方法。我该怎么做？

编辑 我的问题的小图表：

红线代表可见性。因此，当用户更改选项卡时，仅调用stateChanged，tab 0 平滑地更改为 tab 1。当我使用setSelectedIndex时，tab 0 立即被 tab 1 替换，然后我才能从stateChanged 看到我想要的动画，所以用户会看到一个闪光。

Answer 1

我找到了问题的真正原因。

这是线程问题，而不是动画本身。我在 EDT 外打电话给setSelectedIndex，所以我的 JTabbedPane 立即更新，然后执行了来自 EDT 的动画。

答案是：

public void setSelectedTab(final int tab) throws InterruptedException, InvocationTargetException{
    if(!SwingUtilities.isEventDispatchThread()){
        SwingUtilities.invokeAndWait(new Runnable() {
            @Override
            public void run() {
                animatedTabbedPane.setSelectedIndex(tab);
            }
        });
    }
    else
        animatedTabbedPane.setSelectedIndex(tab);
}

在 EDT 中更改标签不会再导致不需要的闪光。

Answer 2

一种方法是在每个标签的内容中添加AncestorListener。让侦听器触发所需的效果，因为将选项卡添加到或从可见性中删除。

import java.awt.EventQueue;
import java.util.Date;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTabbedPane;
import javax.swing.event.AncestorEvent;
import javax.swing.event.AncestorListener;

/**
 * @see http://stackoverflow.com/a/17993449/230513
 */
public class Test {

    private void display() {
        JFrame f = new JFrame("Test");
        final JTabbedPane jtp = new JTabbedPane();
        jtp.add("One", createPanel());
        jtp.add("Two", createPanel());
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(jtp);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

    private JPanel createPanel() {
        JPanel panel = new JPanel();
        final JLabel label = new JLabel(new Date().toString());
        panel.add(label);
        panel.addAncestorListener(new AncestorListener() {
            @Override
            public void ancestorAdded(AncestorEvent event) {
                // start animation
                label.setText(new Date().toString());
            }

            @Override
            public void ancestorRemoved(AncestorEvent event) {
                // stop animation
            }

            @Override
            public void ancestorMoved(AncestorEvent event) {
            }
        });
        return panel;
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                new Test().display();
            }
        });
    }
}