一.消息機(jī)制

OC調(diào)用方法是動(dòng)態(tài)調(diào)用調(diào)用未實(shí)現(xiàn)的方法編譯不報(bào)錯(cuò) 方法調(diào)用的本質(zhì)是發(fā)送消息

import <objc/message.h>
[p eat];
[p performSelector:@selector(eat)];

objc_msgSend();
Xcode5之后使用運(yùn)行時(shí)可設(shè)置
objc_msgSend(p, @selector(eat:),@"??");//傳遞參數(shù)

F36AF365-C511-49F8-B00E-AE53EF06A8E9.png

方法調(diào)用的本質(zhì)是執(zhí)行performSelector 把一個(gè)方法名轉(zhuǎn)化成一個(gè)方法編號根據(jù)這個(gè)方法編號去方法列表中查找對應(yīng)的方法調(diào)用方法的實(shí)現(xiàn)

二.交換方法

參考http://www.itdecent.cn/p/9e3cf04f3dc8

#import <Foundation/Foundation.h>
@interface NSArray (ldd)

@end

#import "NSArray+ldd.h"
#import <objc/message.h>
@implementation NSArray (ldd)
//const char * const LD_Key = "Key";
+ (void)load
{
    [super load];
    
    Method fromMethod = class_getInstanceMethod(objc_getClass("__NSArrayI"), @selector(objectAtIndex:));
    Method toMethod = class_getInstanceMethod(objc_getClass("__NSArrayI"), @selector(ldd_objectAtIndex:));
    method_exchangeImplementations(fromMethod, toMethod);
    
    Method fromMutMethod = class_getInstanceMethod(objc_getClass("__NSArrayM"), @selector(objectAtIndex:));
    Method toMutMethod = class_getInstanceMethod(objc_getClass("__NSArrayM"), @selector(ldd_mutaObjectAtIndex:));
    method_exchangeImplementations(fromMutMethod, toMutMethod);
}
- (id)ldd_objectAtIndex:(NSUInteger)index
{
    if (index < self.count) {
        return [self ldd_objectAtIndex:index];
    }else{
        return nil;
    }
}
- (id)ldd_mutaObjectAtIndex:(NSUInteger)index
{
    if (index < self.count) {
        return [self ldd_mutaObjectAtIndex:index];
    }else{
        return nil;
    }
}
@end

三.動(dòng)態(tài)添加方法

Person * p = [[Person alloc]init];
 //[p eat]; //編譯不過
//動(dòng)態(tài)添加方法
 [p performSelector:@selector(eat) withObject:nil];//編譯的過 運(yùn)行崩

//
//  Person.m
//  test
//
//  Created by 李洞洞 on 27/12/17.
//  Copyright ? 2017年 Minte. All rights reserved.
//

#import "Person.h"
#import <objc/message.h>
@implementation Person
void ldd(id ldself,SEL ldsel){
    NSLog(@"這是一個(gè)動(dòng)態(tài)添加的方法");
    NSLog(@"%@ -- %@",[ldself class],NSStringFromSelector(ldsel));
};
//調(diào)用時(shí)刻：當(dāng)在外界調(diào)用了當(dāng)前類未實(shí)現(xiàn)的方法時(shí)調(diào)用
+ (BOOL)resolveClassMethod:(SEL)sel
{
    return [super resolveClassMethod:sel];
}

+ (BOOL)resolveInstanceMethod:(SEL)sel
{
    if (sel == NSSelectorFromString(@"eat")) {
//IMP:方法的實(shí)現(xiàn) 函數(shù)的入口 函數(shù)名 函數(shù)指針
//types:方法的類型
        class_addMethod([self class], @selector(eat), (IMP)ldd, "V@:");
    }
    return [super resolveInstanceMethod:sel];
}
@end

1385290-b085510875abb98d.png

以上圖中可以通過

NSLog(@"%s",@encode(id));

來獲取
或者用

Method method = class_getInstanceMethod(self,@selector(other));
method_getTypeEncoding(method);

#pragma mark -- 動(dòng)態(tài)添加方法
    Person * p = [[Person alloc]init];
    [p performSelector:@selector(eat:) withObject:@"??"];

#import "Person.h"
#import <objc/message.h>
@implementation Person
void ldd(id ldself,SEL ldsel,id some){
    NSLog(@"這是一個(gè)動(dòng)態(tài)添加的方法");
    NSLog(@"%@ -- %@",[ldself class],NSStringFromSelector(ldsel));
};
+ (BOOL)resolveInstanceMethod:(SEL)sel
{
    if (sel == NSSelectorFromString(@"eat:")) {
        class_addMethod([self class], @selector(eat:), (IMP)ldd, "V@:@");
    }
    return [super resolveClassMethod:sel];
}

四.動(dòng)態(tài)添加屬性

#import <UIKit/UIKit.h>

@interface UIButton (ldd)
/*
 不生成_ld_Title
 不生成 ld_Title的set get
 */
@property NSString * ld_Title;
@end

#import "UIButton+ldd.h"
#import <objc/message.h>
@implementation UIButton (ldd)
const char * const LD_Key = "Key";
- (void)setLd_Title:(NSString *)ld_Title
{
    objc_setAssociatedObject(self, LD_Key, ld_Title, OBJC_ASSOCIATION_COPY_NONATOMIC);
}
- (NSString*)ld_Title
{

    return objc_getAssociatedObject(self, LD_Key);
}
@end

如果不用以上的寫法手動(dòng)實(shí)現(xiàn)set get方法也可以不好的地方是：
靜態(tài)全局變量來保存值如果我這個(gè)對象銷毀了這個(gè)變量保存的值還在此時(shí)你變量保存的值和對象之間并沒任何關(guān)系和我這個(gè)對象無關(guān)了。最好的狀態(tài)是我這個(gè)對象在這個(gè)屬性在對象不在屬性也不在。

 #pragma mark -- 動(dòng)態(tài)添加屬性
 UIButton * btn = [[UIButton alloc]init];
 btn.ld_Title = @"ldd";
 NSLog(@"%@",btn.ld_Title);
 btn.ld_Title = @"999";
 NSLog(@"%@",btn.ld_Title);

或者這么玩

static char * const LD_Key = "Key";
static char * const LD_ButtonKey = "ButtonKey";
- (void)viewDidLoad {
    [super viewDidLoad];
    
    UIButton * button = ({
        UIButton * btn = [[UIButton alloc]init];
        objc_setAssociatedObject(btn, LD_ButtonKey, @"6666", OBJC_ASSOCIATION_RETAIN_NONATOMIC);
        btn;
    });
    [self.view addSubview:button];
    
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        NSLog(@"%@",objc_getAssociatedObject(button, LD_ButtonKey));
    });

    
    
    UIView * view1 = ({
        UIView * view = [[UIView alloc]initWithFrame:CGRectMake(10, 10, 100, 100)];
        view.backgroundColor = [UIColor redColor];
        UITapGestureRecognizer * tap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(view1Click:)];
        NSDictionary * value= @{@"color":[UIColor greenColor]};
        objc_setAssociatedObject(view, LD_Key, value, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
        [view addGestureRecognizer:tap];
        view;
    });
    [self.view addSubview:view1];
}
- (void)view1Click:(UITapGestureRecognizer*)tap
{
    UIView * view = tap.view;
    NSDictionary *value = objc_getAssociatedObject(view, LD_Key);
    view.backgroundColor = value[@"color"];
}
@end

五.字典轉(zhuǎn)模型

#import <Foundation/Foundation.h>
@protocol LDModel <NSObject>
@optional

/**
 模型字段是數(shù)組

 @return {模型字段 : 數(shù)組中存儲(chǔ)的自定義模型的類名}
 */
+ (NSDictionary *)objectClassInArray;

/**
 模型中特殊字段(id...)的替換

 @return {模型中的字段:字典中的特殊字段}
 */
+ (NSDictionary *)propertykeyReplacedWithValue;
@end

@interface NSObject (Prepory)<LDModel>
+ (id)modelWithDict:(NSDictionary*)dict;
@end

#import "NSObject+Prepory.h"
#import <objc/message.h>
@implementation NSObject (Prepory)
+ (id)modelWithDict:(NSDictionary *)dict
{
    id object = [[self alloc]init];
    unsigned int count = 0;
    Ivar * ivarList = class_copyIvarList([self class], &count);
    for (int i = 0; i < count; i++) {
        Ivar  ivar = ivarList[i];
        char const *  name = ivar_getName(ivar);
        NSString * ocName = [NSString stringWithUTF8String:name];
        NSString * key = [ocName substringFromIndex:1];
        id value = nil;
        if ([self respondsToSelector:@selector(propertykeyReplacedWithValue)]) {
            key = [[self propertykeyReplacedWithValue]objectForKey:key];
            
            if (!key) {
                key = [ocName substringFromIndex:1];
            }

            value = dict[key];
            
        }
         key = [ocName substringFromIndex:1];
        
        const char * name1 = ivar_getTypeEncoding(ivar);
        NSString * newName = [[NSString alloc]initWithUTF8String:name1];
        
        
        if ([value isKindOfClass:[NSDictionary class]]&&![key hasPrefix:@"NS"]) {
            newName = [newName stringByReplacingOccurrencesOfString:@"\"" withString:@""];
            newName = [newName stringByReplacingOccurrencesOfString:@"@" withString:@""];
            Class class = NSClassFromString(newName);
            id val = [class modelWithDict:value];
            [object setValue:val forKey:key];
            
            }else if ([value isKindOfClass:[NSArray class]]&&![key hasPrefix:@"NS"]){
                
                if ([self respondsToSelector:@selector(objectClassInArray)]) {
                    id propertyValueType = [[self objectClassInArray] objectForKey:key];
                    Class clas = NSClassFromString(propertyValueType);
                    NSArray * arr = (NSArray*)value;
                    id obj = nil;
                    NSMutableArray * muArr = [NSMutableArray array];
                    for (int i = 0; i < arr.count; i++) {
                       obj = [clas modelWithDict:arr[i]];//key里面放的是區(qū)縣模型//這是一個(gè)模型
                        [muArr addObject:obj];
                    }
                    [object setValue:muArr forKey:key];

                }
                
                
            }else if (value) {

                
                [object setValue:value forKey:key];
                
            }
               
    }
    free(ivarList);
    return object;
}
@end

六.KVO的底層實(shí)現(xiàn)

當(dāng)某個(gè)類的屬性對象第一次被觀察時(shí)，系統(tǒng)就會(huì)在運(yùn)行期間動(dòng)態(tài)地創(chuàng)建該類的一個(gè)派生類，在這個(gè)派生類中重寫基類的任何被觀察屬性的setter方法。派生類在被重寫的setter方法內(nèi)實(shí)現(xiàn)真正的通知機(jī)制
如果原類為Person，那么生成的派生類名為NSKVONotifying_Person。

每一個(gè)類中都有一個(gè)isa指針指向當(dāng)前類，所有系統(tǒng)就是在當(dāng)一個(gè)類的對象第一次被觀察的時(shí)候，系統(tǒng)就會(huì)將isa指針指向動(dòng)態(tài)生成的派生類，從而在被監(jiān)聽屬性賦值時(shí)被執(zhí)行的是派生類的setter方法

鍵值觀察通知依賴于NSObject 的兩個(gè)方法: willChangeValueForKey: 和 didChangevlueForKey:;在一個(gè)被觀察屬性發(fā)生改變之前， willChangeValueForKey: 一定會(huì)被調(diào)用，這就會(huì)記錄舊的值。而當(dāng)改變發(fā)生后，didChangeValueForKey: 會(huì)被調(diào)用，繼而 observeValueForKey: ofObject: change: context: 也會(huì)被調(diào)用。

七.歸檔&解檔

#import <Foundation/Foundation.h>
@interface Person : NSObject<NSCoding>
@property (nonatomic,copy) NSString *name;
@property (nonatomic,copy) NSString *age;
@property (nonatomic,copy) NSString *height;
@end

#import "Person.h"
#import <objc/message.h>
@implementation Person
- (void)encodeWithCoder:(NSCoder *)aCoder
{
    unsigned int count = 0;
    Ivar * ivars = class_copyIvarList([self class], &count);
    for (int i = 0; i < count; i ++) {
        Ivar ivar = ivars[i];
        const char * name = ivar_getName(ivar);
        NSString * key = [NSString stringWithUTF8String:name];
        id value = [self valueForKey:key];
        //歸檔
        [aCoder encodeObject:value forKey:key];
    }
}
- (nullable instancetype)initWithCoder:(NSCoder *)aDecoder
{
    if (self = [super init]) {
        unsigned int count = 0;
        Ivar * ivars = class_copyIvarList([self class], &count);
        for (int i = 0; i < count; i ++) {
            Ivar ivar = ivars[i];
            const char * name = ivar_getName(ivar);
            NSString * key = [NSString stringWithUTF8String:name];
           //解檔
            id value = [aDecoder decodeObjectForKey:key];
            [self setValue:value forKey:key];
        }
    }
    return self;
}
@end

- (void)viewDidLoad {
    [super viewDidLoad];
    Person * p = [[Person alloc]init];
    p.name = @"ldd";
    p.age = @"26";
    p.height = @"1.80";
    NSString * filePath = [@"/Users/fangduozhang/Desktop" stringByAppendingPathComponent:@"LDD.data"];
    [NSKeyedArchiver archiveRootObject:p toFile:filePath];
}
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    Person * p = [NSKeyedUnarchiver unarchiveObjectWithFile:[@"/Users/fangduozhang/Desktop" stringByAppendingPathComponent:@"LDD.data"]];
    NSLog(@"%@---%@---%@",p.name,p.age,p.height);
}

八.數(shù)據(jù)庫動(dòng)態(tài)方案

https://github.com/Buliceli/LDnamicDataBase

鑒于能力有限水平一般理解有誤之處望大俠不吝指出 ThankYou!

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Runtime學(xué)習(xí)筆記

Runtime學(xué)習(xí)筆記

一.消息機(jī)制

二.交換方法

三.動(dòng)態(tài)添加方法

四.動(dòng)態(tài)添加屬性

五.字典轉(zhuǎn)模型

六.KVO的底層實(shí)現(xiàn)

七.歸檔&解檔

八.數(shù)據(jù)庫動(dòng)態(tài)方案

相關(guān)閱讀更多精彩內(nèi)容

友情鏈接更多精彩內(nèi)容

色偷偷精品伊人,欧洲久久精品,欧美综合婷婷骚逼,国产AV主播,国产最新探花在线,九色在线视频一区,伊人大交九 欧美,1769亚洲,黄色成人av

Runtime學(xué)習(xí)筆記

一.消息機(jī)制

二.交換方法

三.動(dòng)態(tài)添加方法

四.動(dòng)態(tài)添加屬性

五.字典轉(zhuǎn)模型

六.KVO的底層實(shí)現(xiàn)

七.歸檔&解檔

八.數(shù)據(jù)庫動(dòng)態(tài)方案

相關(guān)閱讀更多精彩內(nèi)容

友情鏈接更多精彩內(nèi)容

色偷偷精品伊人,欧洲久久精品,欧美综合婷婷骚逼,国产AV主播,国产最新探花在线,九色在线视频一区,伊人大交九欧美,1769亚洲,黄色成人av