从JTextField获取输入并使用它搜索arraytable

Question

I have a arraylist which take a string eg "String searchFor = "London;" and then runs runs in the loop and then shows data related to the string, if I try change the string to String searchFor = tfSearch.getText(); then I get <init> error

I think problem is that the arraylist doesn't wait for the input to be taken from the JTextField

Answer 1

If you read the documentation it says:

Throws:
NullPointerException - if the document is null

So, your JTextField must be null .

You need to execute getText() on a actionListener , for example. Probably, the way you're doing it now, the JTextField is null yet, and you're not waiting for an input from the user. That way, when the user fills that field and clicks Enter , you can get the text from the field.

Check out this example

Add action listener to JTextField