檢查是否為空或零

迅速

if let text = self.textView.text where !text.isEmpty {
    // Do stuff for text
} else {
    // Do stuff for nil text or empty string
}

Objective-C

if (self.textView.text.length > 0){
    // Do stuff for text
}   else {
    // Do stuff for nil text or empty string
}