修改UITextField的placeholder颜色

修改UITextField的placeholder颜色

• 使用属性

@property(nonatomic,copy)   NSAttributedString     *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;

• 重写方法

- (void)drawPlaceholderInRect:(CGRect)rect{    [self.placeholder drawInRect:CGRectMake(0, 10, rect.size.width, 25) withAttributes:@{                                                       NSForegroundColorAttributeName : [UIColor grayColor],                                                       NSFontAttributeName : self.font}];}

• 使用KVC

[self setValue:[UIColor grayColor] forKeyPath:@"_placeholderLabel.textColor"];

运行时(Runtime)

• 苹果官方一套C语言库
• 能做很多底层操作(比如访问隐藏的一些成员变量\成员方法….)
• 访问成员变量举例

unsigned int count = 0;// 拷贝出所有的成员变量列表Ivar *ivars = class_copyIvarList([UITextField class], &count);for (int i = 0; i<count; i++) {    // 取出成员变量    // Ivar ivar = *(ivars + i);    Ivar ivar = ivars[i];    // 打印成员变量名字    XMGLog(@"%s", ivar_getName(ivar));}// 释放free(ivars);