一，效果图。

二，工程图。

三，代码。

ViewController.m

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    
    //TextField
    UITextField *textField=[[UITextField alloc]initWithFrame:CGRectMake(20, 100, 100, 200)];
    textField.backgroundColor=[UIColor redColor];
    textField.text=@"123";
    [self.view addSubview:textField];
    
    NSLog(@"判断textField里面是否为空%i",[self textFieldIsNOTEmpt:textField]);
    
    
}

//判断textField里面是否有空
-(BOOL)textFieldIsNOTEmpt:(UITextField *)textField{
    if ([textField.text stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]].length!=0){
        return YES;
    }else {
        return NO;
    }
}