Java 如何强制JScrollPane中的组件显示
我在显示放置在JScrollPane中的特定组件时遇到问题。我有一个带有GridLayout(1,0)的水平JScrollPane,它包含数量可变的JPanel,每个JPanel都包含图像。这就像是GIF图像中帧的预览。我使用按钮在这些JPanel之间移动(通过更改边框并保留所选内容的索引),但我不知道如何强制JScrollPane显示选中的JPanel(如果可能,将其居中) 所以我想要这个 强制执行此操作: 提前谢谢 编辑:几乎可以使用Java 如何强制JScrollPane中的组件显示,java,swing,jpanel,jscrollpane,Java,Swing,Jpanel,Jscrollpane,我在显示放置在JScrollPane中的特定组件时遇到问题。我有一个带有GridLayout(1,0)的水平JScrollPane,它包含数量可变的JPanel,每个JPanel都包含图像。这就像是GIF图像中帧的预览。我使用按钮在这些JPanel之间移动(通过更改边框并保留所选内容的索引),但我不知道如何强制JScrollPane显示选中的JPanel(如果可能,将其居中) 所以我想要这个 强制执行此操作: 提前谢谢 编辑:几乎可以使用scrollRectToVisible()方法工作代码
scrollRectToVisible()方法工作代码
public class MiniatursPanel extends JPanel{
private int indexOfChosenFrame = 0;
private ArrayList<JPanel> frames;
private JScrollPane scrollPane;
private JPanel innerPanel;
public MiniatursPanel(){
setBorder(BorderFactory.createCompoundBorder(BorderFactory.createRaisedBevelBorder(),BorderFactory.createLoweredBevelBorder()));
setPreferredSize(new Dimension(1200,170));
setLayout(null);
}
public void initialize(){
int width = GifImageStats.getInstance().getWidth();
int height = GifImageStats.getInstance().getHeight();
int numberOfFrames = GifImageStats.getInstance().getNumberOfFrames();
frames = new ArrayList(numberOfFrames);
for (int i = 0; i < numberOfFrames; i++) {
JPanel frameBox = new JPanel();
frameBox.setLayout(new FlowLayout(FlowLayout.CENTER));
JButton button = new JButton(String.valueOf(i+1));
button.setPreferredSize(new Dimension(2*width,2*height));
button.setBackground(Color.white);
button.setFocusable(false);
frameBox.add(button);
frames.add(frameBox);
}
innerPanel = new JPanel();
innerPanel.setLayout(new GridLayout(1,0,10,10));
for (JPanel button : frames) {
innerPanel.add(button);
}
scrollPane = new JScrollPane(innerPanel);
scrollPane.setBounds(10, 10, 1180, 145);
scrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_NEVER);
highlightFrame(frames.get(0));
add(scrollPane);
}
public void nextFrame(){
if (indexOfChosenFrame == frames.size() - 1) {
unhighlightFrame(frames.get(indexOfChosenFrame));
indexOfChosenFrame = 0;
highlightFrame(frames.get(0));
}else{
unhighlightFrame(frames.get(indexOfChosenFrame));
indexOfChosenFrame++;
highlightFrame(frames.get(indexOfChosenFrame));
}
}
public void previousFrame(){
if (indexOfChosenFrame == 0) {
unhighlightFrame(frames.get(0));
indexOfChosenFrame = frames.size()-1;
highlightFrame(frames.get(indexOfChosenFrame));
}else{
unhighlightFrame(frames.get(indexOfChosenFrame));
indexOfChosenFrame--;
highlightFrame(frames.get(indexOfChosenFrame));
}
}
private void highlightFrame(JPanel frame){
Rectangle rect = frame.getBounds();
rect.setBounds(frame.getX()-550, frame.getY(), frame.getWidth()+1050, frame.getHeight());
innerPanel.scrollRectToVisible(rect);
frame.setBorder(BorderFactory.createLineBorder(Color.red,2));
}
private void unhighlightFrame(JPanel frame){
frame.setBorder(null);
}
public-class-minimaturespanel扩展了JPanel{
私有int indexOfChosenFrame=0;
私有数组列表框架;
私有JScrollPane滚动窗格;
私人JPanel内部面板;
公共迷你模型{
setBordOrder(BorderFactory.createCompoundBorder(BorderFactory.createRaisedBevelBorder(),BorderFactory.createLowerdBevelborder());
设置首选尺寸(新尺寸(1200170));
setLayout(空);
}
公共无效初始化(){
int width=GifImageStats.getInstance().getWidth();
int height=GifImageStats.getInstance().getHeight();
int numberOfFrames=GifImageStats.getInstance().getNumberOfFrames();
frames=新的ArrayList(numberOfFrames);
for(int i=0;i
此处的相关方法是JComponent#scrollRectToVisible(矩形)
。必须在滚动窗格视口中的组件上调用它。(在您的情况下,这是具有网格布局的面板,其中包含其他子面板)
传递给此方法的矩形可以是一个子面板的边界。在这种情况下,scoll窗格将执行“最小值”滚动是使给定矩形可见所必需的。如果要确保相应的子面板位于中心,则可以增加此矩形的大小-即,以所需子面板位于中心的方式定义矩形
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.Rectangle;
import java.util.ArrayList;
import java.util.List;
import javax.swing.BorderFactory;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSpinner;
import javax.swing.SpinnerNumberModel;
import javax.swing.SwingConstants;
import javax.swing.SwingUtilities;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class ScrollToVisible
{
public static void main(String[] args)
{
SwingUtilities.invokeLater(new Runnable()
{
@Override
public void run()
{
createAndShowGUI();
}
});
}
private static void createAndShowGUI()
{
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
int n = 20;
final JPanel panel = new JPanel(new GridLayout(1,0));
final List<JComponent> components = new ArrayList<JComponent>();
for (int i=0; i<n; i++)
{
JComponent component = new JLabel(String.valueOf(i), SwingConstants.CENTER);
component.setPreferredSize(new Dimension(100,100));
component.setBorder(BorderFactory.createLineBorder(Color.BLACK));
components.add(component);
panel.add(component);
}
final JScrollPane scrollPane = new JScrollPane(panel);
final JSpinner spinner = new JSpinner(new SpinnerNumberModel(0, 0, n-1, 1));
spinner.addChangeListener(new ChangeListener()
{
JComponent selectedComponent = components.get(0);
@Override
public void stateChanged(ChangeEvent e)
{
selectedComponent.setBorder(BorderFactory.createLineBorder(Color.BLACK));
int index = (Integer)spinner.getValue();
JComponent component = components.get(index);
Rectangle bounds = component.getBounds();
// This would make the component "just" visible:
//panel.scrollRectToVisible(bounds);
// This will center the component:
int cx = bounds.x + bounds.width / 2;
int w = scrollPane.getViewport().getWidth();
Rectangle r = new Rectangle(cx-w/2, bounds.y, w, bounds.height);
panel.scrollRectToVisible(r);
selectedComponent = component;
selectedComponent.setBorder(BorderFactory.createLineBorder(Color.RED));
}
});
f.getContentPane().setLayout(new BorderLayout());
f.getContentPane().add(scrollPane, BorderLayout.CENTER);
f.getContentPane().add(spinner, BorderLayout.NORTH);
f.setSize(800, 300);
f.setLocationRelativeTo(null);
f.setVisible(true);
}
}
最重要的是通过设置与“突出显示”相同大小的空边框,确保组件的大小正确边框。谢谢!它工作得几乎完美。但最后两个组件不会显示,我也不知道为什么。我还尝试手动更改矩形边框,使其更宽,并将其向右移动,但没有成功。滚动条在结尾前停止一个部分。我还将在稍后向原始帖子添加代码,这可能会有所帮助。@user3437263添加了一个编辑。非常感谢您的帮助和您的时间。它现在运行得非常好。问题确实出在我设置为null的borders中。:)
private void highlightFrame(JPanel frame){
Rectangle rect = frame.getBounds();
int c = rect.x + rect.width / 2;
int w = scrollPane.getViewport().getWidth();
int x = c-w/2;
rect.setBounds(x, rect.y, w, rect.height);
innerPanel.scrollRectToVisible(rect);
frame.setBorder(BorderFactory.createLineBorder(Color.red,2));
}
private void unhighlightFrame(JPanel frame){
frame.setBorder(BorderFactory.createEmptyBorder(2, 2, 2, 2));
}