Adding Input Validation

**Snipe** · December 6th, 2017, 12:46 AM

How can I add input validation
"invalid input, number has to be positive"
dialog after
an input of 0 or negative
for length and width?

{
 
String source=ae.getActionCommand();
 
switch (source) {
 
case "Calculate the Area":
System.out.println("Calc 1 Complete");
area=Double.parseDouble(tLength.getText())
*Double.parseDouble(tWidth.getText());
break;

**John Joe** · December 6th, 2017, 03:45 AM

Hi, you can use if condition

if(tLength.getText()<=0 && tWidth.getText()<=0)
{
    System.out.println("invalid input, number has to be positive");
}

**Snipe** · December 6th, 2017, 08:27 AM

Originally Posted by John Joe

Hi, you can use if condition

if(tLength.getText()<=0 && tWidth.getText()<=0)
{
    System.out.println("invalid input, number has to be positive");
}

Thank you for responding. The problem I am having when I enter this is an error "Bad operand for binary operator '<='".

I believe because tLength and tWidth are both String, is there a way to do this while both are String?

**John Joe** · December 6th, 2017, 09:07 AM

Originally Posted by Snipe

I believe because tLength and tWidth are both String, is there a way to do this while both are String?

Yes, You need to convert to int

if((Integer.parseInt(tLength.getText().toString())<=0) && ((Integer.parseInt(tWidth.getText().toString())<=0)))
{
       System.out.println("invalid input, number has to be positive");
}

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