iOS - 通过runtime获取某个类中所有的变量和方法

#import <objc/runtime.h>  

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

var count: UInt32 = 0
let ivars = class_copyIvarList(UIViewController.self, &count)!
for i in 0..<count {
    let namePoint = ivar_getName(ivars[Int(i)])!
    let name = String(cString: namePoint)
    print(name)
}

unsigned int methCount = 0;
Method *meths = class_copyMethodList([UITextField class], &methCount);
    
for(int i = 0; i < methCount; i++) {
        
    Method meth = meths[i];
        
    SEL sel = method_getName(meth);
        
    const char *name = sel_getName(sel);
        
    NSLog(@"%s", name);
}
    
free(meths);

// 修改点位文字颜色
UILabel *placeholderLabel = [self valueForKeyPath:@"_placeholderLabel"];
placeholderLabel.textColor = [UIColor redColor];
// 或者这样
[self setValue:[UIColor grayColor] forKeyPath:@"_placeholderLabel.textColor"];