Redundant 'if' statement less - if-statement

Question

My code is as below
private fun validateInput(): Boolean {
if (etReportRow1.text.toString() == ""
|| etReportRow2.text.toString() == ""
|| etReportRow3.text.toString() == "")
return false
else
return true
}
The compiler tell me
Redundant 'if' statement less... (Ctrl+F1) This inspection reports if
statements which can be simplified to single statements. For example:
if (foo()) { return true } else { return false } can be
simplified to return foo().
Won't the suggested code go into loop?

Answer 1

All statments in the form:
if(condition){
return false
} else {
return true
}
can be simplified into:
return !condition
So in your case it would lead to:
return !(etReportRow1.text.toString() == "" || etReportRow2.text.toString() == "" || etReportRow3.text.toString() == "")
Or:
return
etReportRow1.text.toString().isNotEmpty() &&
etReportRow2.text.toString().isNotEmpty() &&
etReportRow3.text.toString().isNotEmpty()
Note: the isNotEmpty() is an extension method:
public inline fun CharSequence.isNotEmpty(): Boolean = length > 0
To avoid duplicate code you could also use a Sequence:
public fun validateInput() = sequenceOf(etReportRow1, etReportRow2, etReportRow3)
.map { it.text.toString() }
.all { it.isNotEmpty() }

Answer 2

Because a boolean expression evaluates to a boolean value, you can simply return the result of the expression itself, without having to explicitly return true or false.
You can further simplify things using the following single-expression function:
private fun validateInput() = etReportRow1.text.toString() != "" &&
etReportRow2.text.toString() != "" &&
etReportRow3.text.toString() != ""

Answer 3

try
return !(etReportRow1.text.toString() == "" || etReportRow2.text.toString() == "" || etReportRow3.text.toString() == "")

Answer 4

I think this should work:
private fun validateInput() = !(etReportRow1.text.toString.isEmpty()
|| etReportRow2.text.toString().isEmpty()
|| etReportRow3.text.toString().isEmpty() )

Answer 5

Even more concise:
public fun validateInput() = setOf(
etReportRow1, etReportRow2, etReportRow3
).none {
"${it.text}".isEmpty()
}