收到此错误:
Project.reportpane.addComponent(reportpane.java:69) 的线程“AWT-EventQueue-0”java.lang.NullPointerException 中的异常
我无法将 rptinvestment tabbedPane 添加到面板 tabinvestment
公共类报告窗格扩展 JPanel {
JTabbedPane rpt;
JPanel tabcashflow;
JPanel tabinvestment;
JPanel tabexchangerates;
JTabbedPane rptinvestment;
JPanel tabofficial;
JPanel tabdem;
JPanel tabcommodities;
public reportpane() {
rpt = new JTabbedPane();
tabcashflow = new JPanel();
tabinvestment = new JPanel();
tabexchangerates = new JPanel();
tabofficial = new JPanel();
tabdem = new JPanel();
tabcommodities = new JPanel();
rpt.add("Cashflow", tabcashflow);
rpt.add("Investement", tabinvestment);
rpt.add("Exchange rates", tabexchangerates);
rpt.setBackground(new Color(255, 255, 255));
rpt.setFont(new Font("sansserif", Font.PLAIN, 14));
rpt.setTabPlacement(javax.swing.JTabbedPane.TOP);
rpt.setBorder(BorderFactory.createEmptyBorder());
rpt.setSize(750, 500);
rptinvestment = new JTabbedPane();
rptinvestment.add("Official", tabofficial);
rptinvestment.add("DEM", tabdem);
rptinvestment.add("Commodities", tabcommodities);
rptinvestment.setBackground(new Color(255, 255, 255));
rptinvestment.setFont(new Font("sansserif", Font.PLAIN, 14));
rptinvestment.setTabPlacement(JTabbedPane.TOP);
rptinvestment.setBorder(BorderFactory.createEmptyBorder());
rptinvestment.setSize(750, 500);
addComponent(tabinvestment, rptinvestment, 0, 0, 675, 570);
addComponent(this, rpt, 10, 10, 675, 570);
this.setLayout(new BorderLayout());
this.setBackground(Color.WHITE);
this.setBorder(null);
this.revalidate();
this.repaint();
}
public void addComponent(Container container, Component c, int x, int y, int width, int height) {
c.setBounds(x, y, width, height);
container.add(c);
}
}