从 JTextField 检索文本并将其存储在另一个类的对象中

Question

我目前正在开发一个基于 GUI 的应用程序，并使用 netbeans 7.1 的代码生成功能以及我自己的一些自定义代码，以使我的生活更轻松。

我拥有的是一个 JTextbox 数组，我需要从中检索文本并将其存储在不同类的对象数组中的相应对象中。

问题是我在提交数据后收到几个运行时异常。

以下是我的代码的一些相关片段：

用于创建组件的自定义代码：

plnlabel = new javax.swing.JLabel[3];
plntext = new javax.swing.JTextField[3];
int i;
for(i=0;i<3;i++)
{
    plnlabel[i] = new JLabel("Player "+(i+1)+": ");
    plnlabel[i].setVisible(false);
    plntext[i] = new JTextField("Player"+(i+1)+" Name");
    plntext[i].setVisible(false);
}

我有 3 个公共数据成员

public int plnum;
public int size;
public Player [] players;

现在这是触发异常的提交按钮的代码：

 private void namesubActionPerformed(java.awt.event.ActionEvent evt)                                        
{                                            
    plnum = nop.getSelectedIndex()+1;
    namesub.setVisible(false);
    customizelabel.setVisible(true);
    plnamelabel.setVisible(false);
    int i;
    for(i=0;i<plnum;i++)
    {
        plnlabel[i].setVisible(false);
        plntext[i].setVisible(false);
        players[i].setName(plntext[i].getText());
    }
    sizeb.setVisible(true);
    sizesel.setVisible(true);
    sizesub.setVisible(true);
    pack();
}

这是大量的异常列表：

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at snakesnladders.SnakesnLadders.namesubActionPerformed(SnakesnLadders.java:146)
    at snakesnladders.SnakesnLadders.access$000(SnakesnLadders.java:12)
    at snakesnladders.SnakesnLadders$1.actionPerformed(SnakesnLadders.java:86)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2018)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2341)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
    at java.awt.Component.processMouseEvent(Component.java:6505)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3321)
    at java.awt.Component.processEvent(Component.java:6270)
    at java.awt.Container.processEvent(Container.java:2229)
    at java.awt.Component.dispatchEventImpl(Component.java:4861)
    at java.awt.Container.dispatchEventImpl(Container.java:2287)
    at java.awt.Component.dispatchEvent(Component.java:4687)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4832)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4492)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4422)
    at java.awt.Container.dispatchEventImpl(Container.java:2273)
    at java.awt.Window.dispatchEventImpl(Window.java:2713)
    at java.awt.Component.dispatchEvent(Component.java:4687)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:707)
    at java.awt.EventQueue.access$000(EventQueue.java:101)
    at java.awt.EventQueue$3.run(EventQueue.java:666)
    at java.awt.EventQueue$3.run(EventQueue.java:664)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
    at java.awt.EventQueue$4.run(EventQueue.java:680)
    at java.awt.EventQueue$4.run(EventQueue.java:678)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:677)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:211)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:128)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:117)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:113)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:90)

我不知道出了什么问题用我的代码。进行了一些试验和错误，我唯一想到的是，如果我将 getText() 数据存储在按钮单击事件方法中的局部变量中，那么就不会出现错误。

我基本上可以打印 getText() 数据，但无法将其存储在数据成员players[]中。

有人知道这件事吗？

Answer 1

添加

players[i] = new Player();

在使用 players[i] 之前

Answer 2

看来您从未初始化过玩家数组。尝试：

public Player [] players = new Player[3];