在其外部函数中使用for循环中的值 [英] Using values from a for loop in a function outside of it

问题描述

我需要获取从for循环中找到的值，以在不在循环内的函数中使用，而且我不知道该怎么做.我希望完成的工作是从哈希图中的键中提取值，然后仅在选择了该行(使用ListSelectionListener)后才在JTable 中进行绘制.这样，我可以避免绘制一百张表的图形，这样可以节省大量时间.我也在使用DefaultTableModel.

I need to take values that I find from inside a for loop to use in a function that isn't inside the loop, and I can't figure out how to do this. What I am hoping to accomplish is to extract values from a key in a hashmap to then plot in a JTable only if that row is selected (using a ListSelectionListener). This way, I can avoid graphing a hundred tables which would save a lot of time. Also I am using DefaultTableModel.

这是我的for循环:

tableMaker(model);
for(Map.Entry<String,NumberHolder> entry : entries)
{   
  //add rows for each entry of the hashmap to the table             

  double[] v = new double[entry.getValue().singleValues.size()];
  int i = 0;
  for(Long j : entry.getValue().singleValues)
  {
    v[i++] = j.doubleValue();
  }                  
  //right here I need to take "v" 
  //and use it in my tableMaker function for that specific row
}                  

在我的tableMaker函数中，我创建我的JTable并添加一个ListSelectionListener，希望在其中选择行时创建直方图并将其添加到我的lowerPanel中.这是一些代码.我需要v以便创建数据集.

In my tableMaker function, I create my JTable and add a ListSelectionListener, where I hope to create a histogram when a row is selected and add it to my lowerPanel. This is some of the code. I need v so that I can create the dataSet.

public static void tableMaker(DefaultTableModel m)
{
   JPanel lowerPanel = new JPanel();

   //create table here

   frame.getContentPane().add(lowerPanel, BorderLayout.SOUTH);
   table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);

    table.getSelectionModel().addListSelectionListener(
            new ListSelectionListener() {

            @Override
            public void valueChanged(ListSelectionEvent e) {
                if (!e.getValueIsAdjusting()) {
                    JFreeChart chart = ChartFactory.createHistogram(
                        plotTitle, xaxis, yaxis, dataset, orientation,
                        show, toolTips, urls);                      
                //  lowerPanel.add(chart);
                //  lowerPanel.revalidate();
                }
            }
        });
}

推荐答案

我认为您正在尝试实施此处.不必每次尝试创建一个新图表，而是在ChartPanel中创建一个图表并保留对其XYPlot的引用.然后，您可以在ListSelectionListener中使用plot.setDataset()来更新图表.在此示例中，ChangeListener从现有的List<XYDataset>获取所需的数据集.在此示例中，按钮的ActionListener每次调用时都会生成数据集.

I sense that you are trying to implement the approach outlined here. Instead of trying to create a new chart each time, create a single chart in a ChartPanel and retain a reference to its XYPlot. In your ListSelectionListener, you can then use plot.setDataset() to update the chart. In this example, a ChangeListener fetches the desired dataset from an existing List<XYDataset>. In this example, a button's ActionListener generates the dataset each time it is called.

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