如何获取JList中的选定面板元素（覆盖选定的元素）

Question

我有JList的ChartPanel s。当我试图选择元素时，我无法直观地看到列表中实际选择了哪些元素。在节目级听众正在正常工作。

如何从视觉上选择我的图表面板列表？或者如何用不透明颜色叠加这些元素？

期望的结果：

这里是在此基础上example代码：

import java.awt.BorderLayout; 
import java.awt.Color; 
import java.awt.Component; 
import java.awt.Dimension; 
import java.awt.EventQueue; 
import java.util.Random; 

import javax.swing.DefaultListCellRenderer; 
import javax.swing.DefaultListModel; 
import javax.swing.JFrame; 
import javax.swing.JList; 
import javax.swing.JPanel; 
import javax.swing.JScrollPane; 
import javax.swing.ListSelectionModel; 

import org.jfree.chart.ChartFactory; 
import org.jfree.chart.ChartPanel; 
import org.jfree.chart.JFreeChart; 
import org.jfree.chart.plot.PlotOrientation; 
import org.jfree.data.xy.XYSeries; 
import org.jfree.data.xy.XYSeriesCollection; 

/** 
* @see https://stackoverflow.com/a/40445144/230513 
*/ 

public class ThumbnailChartsJList{ 

public static JScrollPane scrollPane; 
public static JList chartList; 

private static final int W = 200; 
private static final int H = W; 
private static final int N = 100; 
private static final int NumberCharts = 20; 
private static final Random random = new Random(); 



public static void main(final String[] args) { 

    EventQueue.invokeLater(new Runnable() { 

     @Override 
     public void run() { 
      JFrame f = new JFrame("Test"); 
      JPanel panel = new JPanel(new BorderLayout()); 

      ChartPanel chartp = createChart(); 

      DefaultListModel listModel = new DefaultListModel(); 
      for (int i=0; i<NumberCharts; i++){ 
       listModel.addElement(chartp); 
      } 


      chartList = new JList(listModel); 
      chartList.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION); 
      chartList.setCellRenderer(new ListRenderer()); 
      chartList.setVisibleRowCount(0); //0 - dynamic rows 
      chartList.setLayoutOrientation(JList.HORIZONTAL_WRAP); 

      chartList.setSelectionForeground(Color.RED); 

      scrollPane = new JScrollPane(chartList, 
        JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, 
        JScrollPane.HORIZONTAL_SCROLLBAR_NEVER); 


      panel.add(scrollPane, BorderLayout.CENTER); 
      f.setPreferredSize(new Dimension(900,700)); 
      f.setContentPane(panel); 
      f.pack(); 
      f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
      f.setVisible(true); 
     } 
    }); 

} 

private static ChartPanel createChart() { 
    final XYSeries series = new XYSeries("Data"); 
    for (int i = 0; i < random.nextInt(N) + N; i++) { 
     series.add(i, random.nextGaussian()); 
    } 
    XYSeriesCollection dataset = new XYSeriesCollection(series); 

    JFreeChart chart = ChartFactory.createXYLineChart("Random", "Domain", 
     "Range", dataset, PlotOrientation.VERTICAL, false, false, false); 
    ChartPanel chartPanel = new ChartPanel(chart, W, H, W, H, W, H, 
      false, true, true, true, true, true){ 
     @Override 
     public Dimension getPreferredSize() { 
     return new Dimension(W, H);} 
    }; 
    chartPanel.getChart().removeLegend(); 
    return chartPanel; 

} 

static class ListRenderer extends DefaultListCellRenderer { 

    @Override 
    public Component getListCellRendererComponent(JList chartList, Object 
     value, int index, boolean isSelected, boolean cellHasFocus) {  
     return (ChartPanel) value; 
    } 

} 

} 

Answer 1

在你ListCellRenderer，调节基础上的isSelected值的背景色。也可以更改图表本身。下面的片段更新了图表的背景颜色;或者，您可以更改绘图的背景Alpha。

static class ListRenderer extends DefaultListCellRenderer { 

    @Override 
    public Component getListCellRendererComponent(JList chartList, Object 
     value, int index, boolean isSelected, boolean cellHasFocus) { 
     ChartPanel chartPanel = (ChartPanel) value; 
     if (isSelected) {chartPanel.getChart().setBackgroundPaint(Color.red);} 
     else {chartPanel.getChart().setBackgroundPaint(Color.white);} 
     return chartPanel; 
    } 
}