我正在开发Java GUI项目，现在我有两个框架。 我在第一帧中声明了一堆数组，但是我想将存储在数组中的数据显示在第二帧中？ 我怎样才能做到这一点 ？当我刚创建一个返回数组的方法时，它表示不兼容的类型，String []不能转换为String。 我想在JTextArea中显示这些数据。 以下是我在第一帧中的代码：
class Bun extends javax.swing.JFrame {
String decimal = "0.00";
DecimalFormat df = new DecimalFormat(decimal);
public final String [] bname = new String [] {"Tuna Sandwich","Garlic Bread","Redbean Bun"};
public static final double [] bprice = new double [] {1.20, 1.50, 1.50};
public static double [] bsub = new double [] {0,0,0};
public static int [] bquantity = new int[] {0,0,0};
public double bsubtotal=0;
public static String [] order;
public boolean setorder()
{
for(int counter=0;counter<bquantity.length;counter++)
{
if(bquantity[counter]>0){
calculatesub();
return true;}
}
return false;
}
public void takeorder()
{
for(int counter=0;counter<bname.length;counter++){
if(setorder()==true)
order[counter]=(bname[counter]+" x "+bquantity[counter]+" - RM "+bsub[counter]);
}
}
public String [] getorder()
{
return order;
}
以下是我的第二帧代码：
class Payment extends javax.swing.JFrame {
public Payment() {
initComponents();
Bun bun = new Bun();
bun.setorder();
bun.takeorder();
jTextArea1.setText(Arrays.toString(bun.getorder()));
}
当我尝试按下从第一帧访问第二帧的按钮时程序被卡住了，以下是生成的所有错误：
run:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at Bun.takeorder(Bun.java:46)
at Payment.<init>(Payment.java:9)
at Bun.paymentbActionPerformed(Bun.java:518)
at Bun.access$1900(Bun.java:4)
at Bun$20.actionPerformed(Bun.java:316)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
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:6535)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6300)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4891)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4713)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
at java.awt.Container.dispatchEventImpl(Container.java:2280)
at java.awt.Window.dispatchEventImpl(Window.java:2750)
at java.awt.Component.dispatchEvent(Component.java:4713)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
BUILD SUCCESSFUL (total time: 9 seconds)
请帮帮我，谢谢。