1、设置TextField的占位符显示placeholder_attributedPlaceholder
// 文字属性
NSMutableDictionary *attrs = [NSMutableDictionary dictionary];
attrs[NSForegroundColorAttributeName] = [UIColor grayColor];
// NSAttributedString : 带有属性的文字(富文本技术)
NSAttributedString *placeholder = [[NSAttributedString alloc] initWithString:@"手机号" attributes:attrs];
self.phoneField.attributedPlaceholder = placeholder;
// NSMutableAttributedString *placehoder = [[NSMutableAttributedString alloc] initWithString:@"手机号"];
// [placehoder setAttributes:@{NSForegroundColorAttributeName : [UIColor whiteColor]} range:NSMakeRange(0, 1)];
// [placehoder setAttributes:@{
// NSForegroundColorAttributeName : [UIColor yellowColor],
// NSFontAttributeName : [UIFont systemFontOfSize:30]
// } range:NSMakeRange(1, 1)];
// [placehoder setAttributes:@{NSForegroundColorAttributeName : [UIColor redColor]} range:NSMakeRange(2, 1)];
// self.phoneField.attributedPlaceholder = placehoder;
