Question

以下是我收到的错误消息：

Exception in thread "AWT-EventQueue-0" java.lang.IndexOutOfBoundsException: Index: 2, Size: 2
    at java.util.ArrayList.RangeCheck(ArrayList.java:547)
    at java.util.ArrayList.get(ArrayList.java:322)
    at pie.chart.explorer.alpha.ShowPieChart.<init>(ShowPieChart.java:28)
    at pie.chart.explorer.alpha.PieChartMain.jButton2ActionPerformed(PieChartMain.java:101)
    at pie.chart.explorer.alpha.PieChartMain.access$100(PieChartMain.java:22)
    at pie.chart.explorer.alpha.PieChartMain$2.actionPerformed(PieChartMain.java:63)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
    at java.awt.Component.processMouseEvent(Component.java:6267)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
    at java.awt.Component.processEvent(Component.java:6032)
    at java.awt.Container.processEvent(Container.java:2041)
    at java.awt.Component.dispatchEventImpl(Component.java:4630)
    at java.awt.Container.dispatchEventImpl(Container.java:2099)
    at java.awt.Component.dispatchEvent(Component.java:4460)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4577)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4238)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4168)
    at java.awt.Container.dispatchEventImpl(Container.java:2085)
    at java.awt.Window.dispatchEventImpl(Window.java:2478)
    at java.awt.Component.dispatchEvent(Component.java:4460)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
BUILD SUCCESSFUL (total time: 14 seconds)

以下是代码：

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package pie.chart.explorer.alpha;

import java.awt.Color;
import java.awt.FlowLayout;
import java.util.ArrayList;
import java.util.Iterator;
import javax.swing.JFrame;

/**
 *
 * @author Andrew
 */
public class ShowPieChart extends JFrame {

    PiePanel pieChart;

    public ShowPieChart(ArrayList<Float> val, ArrayList<Color> col) {
        super("Pie Chart");
        int index = 1;
        setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
        FlowLayout flow = new FlowLayout();
        pieChart = new PiePanel(val.size());
        for(Iterator<Float> i = val.iterator(); i.hasNext(); )  {
         pieChart.addSlice(col.get(index), val.get(index));
         index++;
        }
        setLayout(flow);
        add(pieChart);
        setVisible(true);
    }
}

我已经尝试了很多东西来解决这个问题，但我不知道为什么我仍然会继续得到一个IndexOutOfBoundsException。据我所知，我很确定这是正确的！你能帮忙吗？

Answer 1

索引初始化应该是：

int index = 0;

因为索引的值介于0和lenght-1

之间

Answer 2

异常显示您正在尝试访问索引2，但该列表的大小仅为2.将索引变量初始化为0，因为列表索引（如数组索引）从0开始并一直运行到{{1 }}

Answer 3

正如其他人已经指出的那样，让您在没有例外情况下运行代码的最小变化是在index设置0。但我也会完全重写你的for循环，我认为这是一种更好的编码风格。

int dataSize = val.size();
pieChart = new PiePanel(dataSize);
for (int i = 0; i < dataSize; i++) {
    pieChart.addSlice(col.get(i), val.get(i));
}

您不需要使用Iterator，因为您永远不会在for循环内访问它。更好地使用数字索引，您可以在for定义中引入它，并在每次循环时自动递增。

Answer 4

除了其他人所说的，你无处增加你的迭代器：

for (Iterator<Float> i = val.iterator(); i.hasNext(); ) {
    pieChart.addSlice(col.get(index), val.get(index));
    index++;
}

您需要执行以下操作，否则此循环将永远不会终止。

for (Iterator<Float> i = val.iterator(); i.hasNext(); i.next()) …

但无论如何还不清楚你需要这个迭代器。

Answer 5

index变量应该从0开始。如果数组的大小是 n 那么它的索引从 0 开始到 n-1 < /强>

Answer 6

索引应初始化为0。

索引超出ArrayList中的范围异常

6 个答案: