Javaswing the Input dialog box, click Cancel to throw exception resolution

When doing the product management system, encountered a problem:

When you get an input Box dialog box, String textprice = Joptionpane.showinputdialog ("Please enter the price increase (minus) to be adjusted");

If you click Cancel at this point, an exception will be thrown: java.lang.NullPointerException.

Cause: Clicking Cancel does not produce a string object.

Workaround:

1                 DoublePrice = 0;2String Textprice =Joptionpane3. Showinputdialog ("Please enter the price increase (minus) amount to be adjusted"));4 5                 if(Textprice = =NULL) {6                     return;7                 }8                 Else if(Textprice.equals ("")){9Joptionpane.showmessagedialog (NULL, enter the price increase (minus) amount to adjust, prompt message, joptionpane.error_message);Ten                     return ; One                 } A                 Else{ -                     Try { -Price =double.parsedouble (textprice); the                         if(Pid.changeprice (Price)) { -Joptionpane.showmessagedialog (NULL, "Price adjustment is complete! "); -                         } -}Catch(Exception E1) { +Joptionpane.showmessagedialog (NULL, "wrong input! "); -                     } +  A                 } at}

View Code

Javaswing the Input dialog box, click Cancel to throw exception resolution