如何检测 UITextView 中的文本为空？

Question

It is easy for UITextField to check empty text...But I have a custom UITextView.If I have input text like @" "; We don't know what I input,but only can read the length of the text. How can I detect the empty text like "\\n" , "", " "?Any idea?

Answer 1

You can check it:

if(![[textField.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] length]) {
   //string is all whitespace or newline

}

Answer 2

使用- (NSString *)stringByTrimmingCharactersInSet:(NSCharacterSet *)set和空白字符集并检查结果字符串的长度。

Answer 3

For Swift 5.1

    if textView.text.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty {
        // TextView is empty (or only has whitespaces and newlines) then ...
        // buttonSend.isEnabled = false
    } else {
        // TextView has some text, then ...
        // buttonSend.isEnabled = true
    }

Answer 4

You can check through counting characters if there will no character in uitextview then characters count will be 0 and we can check on it's base:

if(yourTextView.text.characters.count == 0)
    {
        //if empty then
    }
    else
    {
       //if not empty then
    }