判断 UITextField 输入的全是空格

UITextField *tf = [alertView textFieldAtIndex:0];//获得输入框

if(self.selectArray.count < 6)

{

NSString *temp = [tf.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];

//看剩下的字符串的长度是否为零

if ([temp length]== 0) {

[UIAlertView alertViewWithTitle:@"请输入标签" message:@"" cancelButtonTitle:@"确定" otherButtonTitles:nil onDismiss:^(NSInteger buttonIndex) {

} onCancel:^{

}];

return;

}