如下情况，在写add之前都没问题，写上add就报错？这是为什么？

Question

package com.imooc;//（报错一）import java.awt.FlowLayout;import java.awt.GridLayout;import javax.swing.JCheckBox;import javax.swing.JFrame;import javax.swing.JLabel;import javax.swing.JPanel;import javax.swing.UIManager;public class LottoMadness extends JFrame {private static final long serialVersionUID = 1L;JPanel[] row=new JPanel[6];//创建组件JCheckBox[] check=new JCheckBox[2];JLabel quick=new JLabel("Quick");JLabel personal=new JLabel("Personal");public LottoMadness(){//创建外框super("Lotto Madness");setSize(600,400);setLookAndFeel();setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);setVisible(true);//分配空间for(int i=0;i<6;i++){row[i]=new JPanel();}for(int i=0;i<2;i++){check[i]=new JCheckBox();}//添加组件，管理器GridLayout layout=new GridLayout(6,1,1,1);setLayout(layout);for(int i=0;i<6;i++){add(row[i]);//（报错二）}// FlowLayout layout0=new FlowLayout(FlowLayout.CENTER);}public void setLookAndFeel(){try{UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");}catch(Exception e){System.out.println("setLookAndFeel出错"+e);}}/*** @param args*/public static void main(String[] args) {// TODO Auto-generated method stubnew LottoMadness();}}

Answer 1

这add应该是对的吧。
我这里运行起来没有问题。

Answer 2

我的myeclipse6.5也出现了这个问题，我是这样修改的，先装jdk-7u79-windows-x64,然后右击项目-＞Build Path->confidure Build Path->Java Build Path->Libraries->JRE System Library[Myexlipse 6.5]->Edit->Alternate JRE->Installed JRES->Add->Browse选择你新安装的jre地址就可以了，希望可以帮到你

Answer 3

add方法的参数类型是Componet，而row[i]的类型是JPanel，所以会报错