Writing Data to a Sequential Data File - Java Programming: Comprehensive Concepts and Techniques - page 516

If any of the text boxes are empty, the method returns false to the calling
method (line 208). Otherwise, it returns true (line 212), and the program con-
tinues with the actionPerformed() method in order to write the data.

Adding a Method to Clear the Fields and Return the Focus

The clearFields() method is a user-defined method that clears all of the
TextFields in the BillPayer interface window and returns the focus to the first
field, Account Number. The clearField() method is called after the user clicks the
Submit button and the data is written to the data file.
Figure 8-29 displays the code for the clearFields() method. Lines 219 through
226 set each field's text to a null, or empty, string (""). Line 227 then moves the
insertion point to the first field, the Account Number field, with the
requestFocus() method.

215
216

public void clearFields ()

217 {

218 //Clear fields and reset the focus

219 acctNum.setText ( "" ) ;

220 pmt.setText ( "" ) ;

221 firstName.setText ( "" ) ;

222 lastName.setText ( "" ) ;

223 address.setText ( "" ) ;

224 city.setText ( "" ) ;

225 state.setText ( "" ) ;

226 zip.setText ( "" ) ;

227 acctNum.requestFocus () ;

228 }

FIGURE 8-29

The following step codes the clearFields() method.

To Code the clearFields() Method

1. Enter the code in Figure 8-29.
TextPad displays the code for the clearFields() method (Figure 8-30).

code to clear text boxes

code to position insertion point

FIGURE 8-30