好吧,我正在尝试设置我的图标图像,并且我一直收到此错误....
代码:
public static void browser(){
Image myicon = null;
myicon.equals("images/icon.gif");
try {
UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
} catch (ClassNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (InstantiationException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IllegalAccessException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (UnsupportedLookAndFeelException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
JFrame frame = new JFrame("Kloke - Become invisable.");
frame.setSize(350, 100);
frame.setResizable(false);
frame.setIconImage(myicon);
错误:
Exception in thread "main" java.lang.NullPointerException
at web.browser(web.java:14)
at Checkupdate.main(Checkupdate.java:102)
PS。我是java的新手,所以请随意对待我,好像我不知道我在做什么(PSS第14行是我初始化'myicon'变量的地方。)
答案 0 :(得分:2)
尝试在尚未实例化的对象上调用任何实例方法将导致NullPointerException
。您需要实例化myicon
Image myicon = ImageIO.read(new File("images/icon.gif"));
答案 1 :(得分:0)
问题在这里Image myicon = null;
myicon.equals("images/icon.gif");
您正在将myicon设置为null并进行比较,因此编译器会抛出NullPointerException