textField.placeholder颜色的修改方式，为自己做一个记录，希望能帮到有需要的朋友。
UITextField *textField = [[UITextField alloc] initWithFrame:CGRectMake(15, 128, Kwidth - 30, 21)];
// textField.text = @"输入你想要直播的标题";
textField.delegate = self;
textField.placeholder = @"输入你想要直播的内容";
//更改placeholder 的颜色
NSMutableDictionary *dict = [NSMutableDictionary dictionary];
dict[NSForegroundColorAttributeName] = [UIColor whiteColor];
NSAttributedString *attribute = [[NSAttributedString alloc] initWithString:textField.placeholder attributes:dict];
[textField setAttributedPlaceholder:attribute];
textField.textAlignment = NSTextAlignmentCenter;
textField.textColor = [UIColor whiteColor];
[view addSubview:textField];
