Re: JFrame disaperes after creation.
iMohed@live.se wrote:
Hello guys. what am I doing wrong here ?? Im trying to create a
JFrame from a controler class with
View v = new view(this);
MFrame[] frames = new MFrame[2];
for (MFrame mF : frames) {
mF = new MFrame();
mF.setLayout(new BoxLayout(mF, BoxLayout.PAGE_AXIS));
mF.add(mF.name);
mF.add(mF.msg);
mF.buttons.setLayout(new BoxLayout(mF.buttons,
BoxLayout.LINE_AXIS));
int i = 0;
for (JButton jB : mF.sSP) {
jB = new JButton(type[i]);
// ImageIcon iI = new ImageIcon();
//jB.setIcon(iI);
mF.buttons.add(jB);
jB.addActionListener(ssp);
jB.setActionCommand(type[i]);
i++;
}
mF.add(mF.buttons);
mF.add(mF.status);
mF.add(mF.score);
add(mF);
}
then when i try to call
v.frames[0].msg.setText("Hello");
I get a nullpointerexception. Now why is that. I just dont get it.
Try run this for a hint:
public class ForLoops {
public static void main(String[] args) {
String[] sa = new String[2];
try {
for(String s : sa) {
s = new String("ABC");
}
String s2 = sa[0].substring(0, 1);
System.out.println("No exception");
} catch(NullPointerException npe) {
System.out.println("Exception");
}
try {
for(int i = 0; i < sa.length; i++) {
sa[i] = new String("ABC");
}
String s2 = sa[0].substring(0, 1);
System.out.println("No exception");
} catch(NullPointerException npe) {
System.out.println("Exception");
}
}
}
Arne