How to find user put nothig in JTextField?

[mira yang]

the user give a nickname when login,but how to find he put nothing?
Thanks!

[Sebastiaan Kortleven]

if (textfield.getText().equals("")) System.out.println("Nothing entered");

[Java Programmer]

Do following:
1. String temp=new String("");
2. if((temp.compareTo(textField.getText())==0)

[Java Programmer]

Do following:
I think This will work :
//---Your Code
String temp=new String("");
if((temp.compareTo(textField.getText())==0){
JOptionPane.showMessageDialog(null,"Enter Nick Name",JOptionPane.ERROR_MESSAGE);
/* plaease check the API for JOptionPane.showMessageDialog() */
//--Your Code

[Gregg Bolinger]

Java Programmer,
We have a Naming Policy that all our members must adhere to. Please read this and adjust your display name accordingly.
You can change your display name here.
It appears that you have been warned about your display name 3 times already. I would like to inform you that not adhering to our Naming Policy can result in your account being locked and possibly your IP being blocked from our site. Please adjust your display name to avoid these actions. Come on...conform...be one of us.

[Carlos Failde]

A similar topic mentions the user of an InputVerifier.

[Ernest Friedman-Hill]

Note, also, that most "Java Programmer"s would write the following code:

String temp=new String("");
if((temp.compareTo(textField.getText())==0){

more efficient, as well as far more readable

if ("".equals(textField.getText()) {

[Robert Tiffer]

I would use

 if ("".equals(textField.getText().trim()) { 

just in case the user had entered whitespace. Too anal? Can't help it, I'm addicted to the trim() method.

[Stefan Wagner]

 if ("".equals(textField.getText().trim ()) { 

just in case the user had entered whitespace. [/qb]<hr></blockquote>
You cannot be sure, whether a whitespace might be a valid input, since we don't know to much of the context it's used.
But of course

 if (textField.getText().equals("")) 

is better readable.
[ April 21, 2004: Message edited by: Stefan Wagner ]

[Jason Steele]

Another example:
if(textBox.getText().trim().length() == 0) { // do stuff }