Runtime:项目应用
2022-03-31 本文已影响0人
东方诗空
动态创建类
- 对应的常用API
动态创建一个类(参数:父类,类名,额外的内存空间)
Class objc_allocateClassPair(Class superclass, const char *name, size_t extraBytes)
注册一个类(要在类注册之前添加成员变量)
void objc_registerClassPair(Class cls)
销毁一个类
void objc_disposeClassPair(Class cls)
获取isa指向的Class
Class object_getClass(id obj)
设置isa指向的Class
Class object_setClass(id obj, Class cls)
判断一个OC对象是否为Class
BOOL object_isClass(id obj)
判断一个Class是否为元类
BOOL class_isMetaClass(Class cls)
获取父类
Class class_getSuperclass(Class cls)
- 动态添加类举例
// 创建类
Class newClass = objc_allocateClassPair([NSObject class], "Dog", 0);
class_addIvar(newClass, "_age", 4, 1, @encode(int));
class_addIvar(newClass, "_weight", 4, 1, @encode(int));
class_addMethod(newClass, @selector(run), (IMP)run, "v@:");
// 注册类
objc_registerClassPair(newClass);
id dog = [[newClass alloc] init];
[dog setValue:@10 forKey:@"_age"];
[dog setValue:@20 forKey:@"_weight"];
[dog run];
NSLog(@"%@ %@", [dog valueForKey:@"_age"], [dog valueForKey:@"_weight"]);
// 在不需要这个类时释放
objc_disposeClassPair(newClass);
实例变量
- 对应的常用API
获取一个实例变量信息
Ivar class_getInstanceVariable(Class cls, const char *name)
拷贝实例变量列表(最后需要调用free释放)
Ivar *class_copyIvarList(Class cls, unsigned int *outCount)
设置和获取成员变量的值
void object_setIvar(id obj, Ivar ivar, id value)
id object_getIvar(id obj, Ivar ivar)
动态添加成员变量(已经注册的类是不能动态添加成员变量的)
BOOL class_addIvar(Class cls, const char * name, size_t size, uint8_t alignment, const char * types)
获取成员变量的相关信息
const char *ivar_getName(Ivar v)
const char *ivar_getTypeEncoding(Ivar v)
例子:
// 获取成员变量信息
Ivar ageIvar = class_getInstanceVariable([Person class], "_age");
NSLog(@"%s %s", ivar_getName(ageIvar), ivar_getTypeEncoding(ageIvar));
//设置和获取成员变量的值
Ivar nameIvar = class_getInstanceVariable([Person class], "_name");
Person *person = [[Person alloc] init];
object_setIvar(person, nameIvar, @"123");
object_setIvar(person, ageIvar, (__bridge id)(void *)10);
NSLog(@"%@ %d", person.name, person.age);
// 成员变量的数量
unsigned int count;
Ivar *ivars = class_copyIvarList([Person class], &count);
for (int i = 0; i < count; i++) {
// 取出i位置的成员变量
Ivar ivar = ivars[i];
NSLog(@"%s %s", ivar_getName(ivar), ivar_getTypeEncoding(ivar));
}
free(ivars);
实战:修改textField的placeholder 字体颜色
- 取出所有成员变量
unsigned int count;
Ivar *ivars = class_copyIvarList([UITextField class], &count);
for (int i = 0; i < count; i++) {
// 取出i位置的成员变量
Ivar ivar = ivars[i];
NSLog(@"%s %s", ivar_getName(ivar), ivar_getTypeEncoding(ivar));
}
free(ivars);
- 查找对应的对象 设置值
UILabel *placeholderLabel = [self.textField valueForKeyPath:@"_placeholderLabel"];
placeholderLabel.textColor = [UIColor redColor];
或者
[self.textField setValue:[UIColor redColor] forKeyPath:@"_placeholderLabel.textColor"];
字典转模型
+ (instancetype)wd_objectWithJson:(NSDictionary *)json
{
id obj = [[self alloc] init];
unsigned int count;
Ivar *ivars = class_copyIvarList(self, &count);
for (int i = 0; i < count; i++) {
// 取出i位置的成员变量
Ivar ivar = ivars[i];
NSMutableString *name = [NSMutableString stringWithUTF8String:ivar_getName(ivar)];
[name deleteCharactersInRange:NSMakeRange(0, 1)];
// 设值
id value = json[name];
[obj setValue:value forKey:name];
}
free(ivars);
return obj;
}
@end
// 字典转模型
NSDictionary *json = @{
@"id" : @20,
@"age" : @20,
@"weight" : @60,
@"name" : @"Jack"
@"no" : @30
};
Person *person = [Person wd_objectWithJson:json];
获取属性
获取一个属性
objc_property_t class_getProperty(Class cls, const char *name)
拷贝属性列表(最后需要调用free释放)
objc_property_t *class_copyPropertyList(Class cls, unsigned int *outCount)
动态添加属性
BOOL class_addProperty(Class cls, const char *name, const objc_property_attribute_t *attributes,
unsigned int attributeCount)
动态替换属性
void class_replaceProperty(Class cls, const char *name, const objc_property_attribute_t *attributes,
unsigned int attributeCount)
获取属性的一些信息
const char *property_getName(objc_property_t property)
const char *property_getAttributes(objc_property_t property)
动态替换方法
获得一个实例方法、类方法
Method class_getInstanceMethod(Class cls, SEL name)
Method class_getClassMethod(Class cls, SEL name)
方法实现相关操作
IMP class_getMethodImplementation(Class cls, SEL name)
IMP method_setImplementation(Method m, IMP imp)
void method_exchangeImplementations(Method m1, Method m2)
拷贝方法列表(最后需要调用free释放)
Method *class_copyMethodList(Class cls, unsigned int *outCount)
动态添加方法
BOOL class_addMethod(Class cls, SEL name, IMP imp, const char *types)
动态替换方法
IMP class_replaceMethod(Class cls, SEL name, IMP imp, const char *types)
获取方法的相关信息(带有copy的需要调用free去释放)
SEL method_getName(Method m)
IMP method_getImplementation(Method m)
const char *method_getTypeEncoding(Method m)
unsigned int method_getNumberOfArguments(Method m)
char *method_copyReturnType(Method m)
char *method_copyArgumentType(Method m, unsigned int index)
选择器相关
const char *sel_getName(SEL sel)
SEL sel_registerName(const char *str)
用block作为方法实现
IMP imp_implementationWithBlock(id block)
id imp_getBlock(IMP anImp)
BOOL imp_removeBlock(IMP anImp)
实战
监听拦截所有的点击事件
@implementation UIControl (Extension)
+ (void)load
{
// hook:钩子函数
Method method1 = class_getInstanceMethod(self, @selector(sendAction:to:forEvent:));
Method method2 = class_getInstanceMethod(self, @selector(wd_sendAction:to:forEvent:));
method_exchangeImplementations(method1, method2);
}
- (void)wd_sendAction:(SEL)action to:(id)target forEvent:(UIEvent *)event
{
NSLog(@"%@-%@-%@", self, target, NSStringFromSelector(action));
// 调用系统原来的实现
[self wd_sendAction:action to:target forEvent:event];
}
@end
数组添加值时 判 nil 拦截
#import <objc/runtime.h>
@implementation NSMutableArray (Extension)
+ (void)load
{
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
// 类簇:NSString、NSArray、NSDictionary,真实类型是其他类型
Class cls = NSClassFromString(@"__NSArrayM");
Method method1 = class_getInstanceMethod(cls, @selector(insertObject:atIndex:));
Method method2 = class_getInstanceMethod(cls, @selector(wd_insertObject:atIndex:));
method_exchangeImplementations(method1, method2);
});
}
- (void)wd_insertObject:(id)anObject atIndex:(NSUInteger)index
{
if (anObject == nil) return;
[self wd_insertObject:anObject atIndex:index];
}
@end
字典key为nil、值时 判 nil 拦截
#import "NSMutableDictionary+Extension.h"
#import <objc/runtime.h>
@implementation NSMutableDictionary (Extension)
+ (void)load
{
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
Class cls = NSClassFromString(@"__NSDictionaryM");
Method method1 = class_getInstanceMethod(cls, @selector(setObject:forKeyedSubscript:));
Method method2 = class_getInstanceMethod(cls, @selector(wd_setObject:forKeyedSubscript:));
method_exchangeImplementations(method1, method2);
Class cls2 = NSClassFromString(@"__NSDictionaryI");
Method method3 = class_getInstanceMethod(cls2, @selector(objectForKeyedSubscript:));
Method method4 = class_getInstanceMethod(cls2, @selector(wd_objectForKeyedSubscript:));
method_exchangeImplementations(method3, method4);
});
}
- (void)wd_setObject:(id)obj forKeyedSubscript:(id<NSCopying>)key
{
if (!key) return;
[self wd_setObject:obj forKeyedSubscript:key];
}
- (id)wd_objectForKeyedSubscript:(id)key
{
if (!key) return nil;
return [self wd_objectForKeyedSubscript:key];
}
@end