谁能帮我找出线索和QUOT除外; AWT-EventQueue的-0＆QUOT;显示java.lang.NullPointerException 65线？ [英] Can anyone help me identify the Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException on Line 65?
本文介绍了谁能帮我找出线索和QUOT除外; AWT-EventQueue的-0＆QUOT;显示java.lang.NullPointerException 65线？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我不断收到运行时错误，说我有螺纹的异常AWT-EventQueue的-0显示java.lang.NullPointerException跟它一[线65]，但对我来说它只是看起来像一个基本的if语句。我可以给一些背景。这架从帧序列，那么一旦选择的状态被发送到包含一个新的帧的呼叫状态A-C的城市。当阿拉巴马州是没有选择的状态。这当前帧只会工作。 （我没有创建其它帧的其他国家，因此他们为什么被注释掉了）我可以忍受的code到它应该是如果有人需要它，但我想，这是一个很大的调用其他框架code开始。
在此先感谢您的帮助大家。
进口的javax.swing *。
进口java.awt中的*。
进口java.awt.event.ActionListener;
java.awt.event中导入*。
进口java.io. *;
进口的java.util。*;公共类WetBulbByLocationFrameStates3扩展的JFrame
{
公众的JLabel stateLabel;
公众的JPanel statePanel =新JPanel（）;
公共的JComboBox stateBox;
公众的String [] UnitedStates的买家= {亚拉巴马号，阿拉斯加，亚利桑那，阿肯色州，加州，科罗拉多，康涅狄格，特拉华州，哥伦比亚特区，佛罗里达，格鲁吉亚，夏威夷，爱达荷，伊利诺伊州，夺宝，阿华，堪萨斯州，肯德基，路易斯安那州，缅因，马里兰，马萨诸塞州，密歇根 明尼苏达，密西西比，密苏里，蒙大拿，内布拉斯加，内华达，新罕布什尔，新泽西，新墨西哥，纽约，北卡罗莱纳州， 北达科他州，俄亥俄，俄克拉荷马，俄勒冈州，宾夕法尼亚州，罗得岛，南卡罗来纳，南达科他州，南太平洋岛屿，田纳西州，得克萨斯 犹他，佛蒙特，弗吉尼亚，华盛顿，西弗吉尼亚州，威斯康星，怀俄明};
公众的String [] canadianProvinces = {亚伯，不列颠哥伦比亚省，曼尼托巴，新不伦瑞克省，纽芬兰和拉布拉多，西北地区，新斯科舍省，努纳武特地区，安大略，爱德华王子岛，魁，萨斯喀彻温省，育空地区};
公共JButton的Next按钮=的新的JButton（下一步）;
公众的JPanel buttonPanel =新JPanel（）;
公共字符串状态;
公共字符串countryGIVEN; 公共WetBulbByLocationFrameStates3（字符串国家）
{
工具箱工具箱= Toolkit.getDefaultToolkit（）;
维尺寸= toolkit.getScreenSize（）;
INT X =（dimensions.width - 315）/ 2;
INT Y =（dimensions.height - 250）/ 2;
的setBounds（X，Y，315，250）;
调用setVisible（真）;
的setResizable（假）;
setDefaultCloseOperation（JFrame.DISPOSE_ON_CLOSE）;
countryGIVEN =国家; nextButton.addActionListener（新ButtonListener3（））; 如果（country.equals（美利坚合众国））
{
stateBox =新的JComboBox（UnitedStates的）;
的setTitle（选择国家）;
stateLabel =新的JLabel（国家）;
}
否则，如果（country.equals（加拿大））
{
stateBox =新的JComboBox（canadianProvinces）;
的setTitle（选择省）;
stateLabel =新的JLabel（省）;
} stateBox.addActionListener（新ComboBoxListener2（））; statePanel.add（stateLabel）;
statePanel.add（stateBox）; 加（statePanel，BorderLayout.CENTER）; buttonPanel.add（Next按钮）; 加（buttonPanel，BorderLayout.SOUTH）;
}
私有类ButtonListener3实现的ActionListener
{
@覆盖
公共无效的actionPerformed（ActionEvent的五）
{
如果（countryGIVEN.equals（美利坚合众国））
{
如果（state.equals（亚拉巴马））
{
JFrame的wbfs1 =新WetBulbByLocationFrameStateGroupA_C（州）;
}
否则，如果（state.equals（阿拉斯加））
{
JFrame的wbfs2 =新WetBulbByLocationFrameStateGroupA_C（州）;
}
否则如果（state.equals（亚利桑那））
{
JFrame的wbfs3 =新WetBulbByLocationFrameStateGroupA_C（州）;
}
否则如果（state.equals（阿肯色））
{
JFrame的wbfs4 =新WetBulbByLocationFrameStateGroupA_C（州）;
}
否则，如果（state.equals（加利福尼亚））
{
JFrame的wbfs5 =新WetBulbByLocationFrameStateGroupA_C（州）;
}
否则如果（state.equals（科罗拉多））
{
JFrame的wbfs6 =新WetBulbByLocationFrameStateGroupA_C（州）;
}
否则如果（state.equals（康涅狄格））
{
JFrame的wbfs7 =新WetBulbByLocationFrameStateGroupA_C（州）;
}
}
}
}
私有类ComboBoxListener2实现的ActionListener
{
@覆盖
公共无效的actionPerformed（ActionEvent的五）
{
状态=（字符串）stateBox.getSelectedItem（）;
}
}
}
选择阿拉巴马PS时，这里的错误。
异常螺纹AWT-EventQueue的-0显示java.lang.NullPointerException
在WetBulbByLocationFrameStates3 $ ButtonListener3.actionPerformed（WetBulbByLocationFrameStates3.java:65）
在javax.swing.AbstractButton.fireActionPerformed（来源不明）
在javax.swing.AbstractButton中的$ Handler.actionPerformed（来源不明）
在javax.swing.DefaultButtonModel.fireActionPerformed（来源不明）
在javax.swing.DefaultButtonModel.set pressed（来源不明）
在javax.swing.plaf.basic.BasicButtonListener.mouseReleased（来源不明）
在java.awt.Component.processMouseEvent（来源不明）
在javax.swing.JComponent.processMouseEvent（来源不明）
在java.awt.Component.processEvent（来源不明）
在java.awt.Container.processEvent（来源不明）
在java.awt.Component.dispatchEventImpl（来源不明）
在java.awt.Container.dispatchEventImpl（来源不明）
在java.awt.Component.dispatchEvent（来源不明）
在java.awt.LightweightDispatcher.retargetMouseEvent（来源不明）
在java.awt.LightweightDispatcher.processMouseEvent（来源不明）
在java.awt.LightweightDispatcher.dispatchEvent（来源不明）
在java.awt.Container.dispatchEventImpl（来源不明）
在java.awt.Window.dispatchEventImpl（来源不明）
在java.awt.Component.dispatchEvent（来源不明）
在java.awt.EventQueue.dispatchEventImpl（来源不明）
在java.awt.EventQueue.access $ 000（来源不明）
在java.awt.EventQueue中的$ 3.run（来源不明）
在java.awt.EventQueue中的$ 3.run（来源不明）
在java.security.AccessController.doPrivileged（本机方法）
在java.security.ProtectionDomain $ 1.doIntersectionPrivilege（来源不明）
在java.security.ProtectionDomain $ 1.doIntersectionPrivilege（来源不明）
在java.awt.EventQueue中的$ 4.run（来源不明）
在java.awt.EventQueue中的$ 4.run（来源不明）
在java.security.AccessController.doPrivileged（本机方法）
在java.security.ProtectionDomain $ 1.doIntersectionPrivilege（来源不明）
在java.awt.EventQueue.dispatchEvent（来源不明）
在java.awt.EventDispatchThread.pumpOneEventForFilters（来源不明）
在java.awt.EventDispatchThread.pumpEventsForFilter（来源不明）
在java.awt.EventDispatchThread.pumpEventsForHierarchy（来源不明）
在java.awt.EventDispatchThread.pumpEvents（来源不明）
在java.awt.EventDispatchThread.pumpEvents（来源不明）
在java.awt.EventDispatchThread.run（来源不明）
解决方案
65号线是这个：
如果（state.equals（亚拉巴马））
如果你去翻previous code，一切都没有初始化状态所以将其值空。
I keep getting a Run Time error that says I am having an Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException it is saying a [line 65] but to me it just looks like a basic if statement. I can give some background. this frame is call from a sequence of frames that is then once the state is selected sent to a new frame that contains states A-C cities. This current frame will work only when Alabama is not the state selected. (I have not created the other frames for the other states hence why they are commented out) I can put up the code to the other frame it is supposed to call if anyone needs it but I figured that this was a lot of code to begin with. Thanks in advance for the help everybody.
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionListener;
import java.awt.event.*;
import java.io.*;
import java.util.*;
public class WetBulbByLocationFrameStates3 extends JFrame
{
public JLabel stateLabel;
public JPanel statePanel = new JPanel();
public JComboBox stateBox;
public String [] unitedStates = {"Alabama", "Alaska", "Arizona", "Arkansas", "California", "Colorado", "Connecticut", "Delaware", "District of Columbia", "Florida", "Georgia", "Hawaii", "Idaho", "Illinois", "Indiana", "Iowa", "Kansas", "Kentucky", "Louisiana", "Maine", "Maryland", "Massachusetts", "Michigan", "Minnesota", "Mississippi", "Missouri", "Montana", "Nebraska", "Nevada", "New Hampshire", "New Jersey", "New Mexico", "New York", "North Carolina", "North Dakota", "Ohio", "Oklahoma", "Oregon", "Pennsylvania", "Rhode Island", "South Carolina", "South Dakota", "South Pacific Islands", "Tennessee", "Texas", "Utah", "Vermont", "Virginia", "Washington", "West Virginia", "Wisconsin", "Wyoming"};
public String [] canadianProvinces = {"Alberta", "British Columbia", "Manitoba", "New Brunswick", "Newfoundland and Labrador", "Northwest Territories", "Nova Scotia", "Nunavut", "Ontario", "Prince Edward Island", "Quebec", "Saskatchewan", "Yukon Territory"};
public JButton nextButton = new JButton("Next");
public JPanel buttonPanel = new JPanel();
public String state;
public String countryGIVEN;
public WetBulbByLocationFrameStates3(String country)
{
Toolkit toolkit = Toolkit.getDefaultToolkit();
Dimension dimensions = toolkit.getScreenSize();
int x = (dimensions.width - 315)/2;
int y = (dimensions.height - 250)/2;
setBounds(x, y, 315, 250);
setVisible(true);
setResizable(false);
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
countryGIVEN = country;
nextButton.addActionListener(new ButtonListener3());
if (country.equals("United States of America"))
{
stateBox = new JComboBox(unitedStates);
setTitle("Select State");
stateLabel = new JLabel("State");
}
else if (country.equals("Canada"))
{
stateBox = new JComboBox(canadianProvinces);
setTitle("Select Province");
stateLabel = new JLabel("Province");
}
stateBox.addActionListener(new ComboBoxListener2());
statePanel.add(stateLabel);
statePanel.add(stateBox);
add(statePanel, BorderLayout.CENTER);
buttonPanel.add(nextButton);
add(buttonPanel, BorderLayout.SOUTH);
}
private class ButtonListener3 implements ActionListener
{
@Override
public void actionPerformed(ActionEvent e)
{
if (countryGIVEN.equals("United States of America"))
{
if (state.equals("Alabama"))
{
JFrame wbfs1 = new WetBulbByLocationFrameStateGroupA_C(state);
}
else if (state.equals("Alaska"))
{
JFrame wbfs2 = new WetBulbByLocationFrameStateGroupA_C(state);
}
else if (state.equals("Arizona"))
{
JFrame wbfs3 = new WetBulbByLocationFrameStateGroupA_C(state);
}
else if (state.equals("Arkansas"))
{
JFrame wbfs4 = new WetBulbByLocationFrameStateGroupA_C(state);
}
else if (state.equals("California"))
{
JFrame wbfs5 = new WetBulbByLocationFrameStateGroupA_C(state);
}
else if (state.equals("Colorado"))
{
JFrame wbfs6 = new WetBulbByLocationFrameStateGroupA_C(state);
}
else if (state.equals("Connecticut"))
{
JFrame wbfs7 = new WetBulbByLocationFrameStateGroupA_C(state);
}
}
}
}
private class ComboBoxListener2 implements ActionListener
{
@Override
public void actionPerformed(ActionEvent e)
{
state = (String)stateBox.getSelectedItem();
}
}
}
PS here's the error when selecting Alabama.
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at WetBulbByLocationFrameStates3$ButtonListener3.actionPerformed(WetBulbByLocationFrameStates3.java:65)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$000(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.awt.EventQueue$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
解决方案
Line 65 is this one:
if (state.equals("Alabama"))
If you look through the previous code, nothing has initialized state so its value will be null.
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