[英]index out of bounds exception in ArrayList
这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)
这是代码:
/*
* 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);
}
}
我已经尝试了很多方法来解决这个问题,但我不知道为什么我仍然不断收到 IndexOutOfBoundsException。 据我所知,我很确定这是正确的? 你能帮我吗?
索引初始化应该是:
int index = 0;
因为索引的值在 0 和lenght-1
之间
例外情况是显示您正在尝试访问索引 2,但列表的大小仅为 2。将您的索引变量初始化为 0,因为列表索引(如数组索引)从 0 开始并运行到size()-1
。
正如其他人已经指出的那样,让您毫无例外地运行代码的最小更改是将index
设置为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
循环中访问它。 最好使用数字索引,您可以在for
定义中引入它,并在每次通过循环时自动递增。
除了其他人所说的之外,您无处增加迭代器:
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()) …
但目前还不清楚你需要这个迭代器做什么。
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 。
索引应初始化为 0。
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