GC的笔记本

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NSObject+ModelExtension.h

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#import <Foundation/Foundation.h>

@protocol NSObjectDelegate <NSObject>

@optional
+ (NSDictionary *)arrayContainModelClass; ///< array 转字典
@optional
+ (NSDictionary *)modelContainModelClass; /// < array 转model

@end


@interface NSObject (ModelExtension)

+ (instancetype)modelWithDict:(id)dict;

@end

NSObject+ModelExtension.m

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#import "NSObject+ModelExtension.h"
#import <objc/runtime.h>

@implementation NSObject (ModelExtension)

+ (instancetype)modelWithDict:(id)dict {
    id obj = [[self alloc] init];
    
    unsigned int count;
    Ivar *ivarList = class_copyIvarList(self, &count);
    for (int i = 0; i < count; i ++) {
        Ivar ivar = ivarList[i];
        
        // 获取成员属性
        NSString *name = [NSString stringWithUTF8String:ivar_getName(ivar)];
        
        // 处理成员属性名 -> 字典中的key 去掉下划线
        NSString *key = [name substringFromIndex:1];
        
        // 根据成员属性名去字典查找对应的value
        id value = dict[key];
        
        // 二级转换: 如果字典中还有字典，也需要把对应的字典转换成模型
        if ([value isKindOfClass:[NSDictionary class]]) {
            
            // 获取成员变量的类型
            NSString *type = [NSString stringWithUTF8String:ivar_getTypeEncoding(ivar)];
            
            // 裁剪类型字符串
            NSRange range = [type rangeOfString:@"\""];
            
            type = [type substringFromIndex:range.location + range.length];
            
            range = [type rangeOfString:@"\""];
            
            type = [type substringFromIndex:range.location];
            
            // 根据字符串类型生成类对象
            Class moduleClass = NSClassFromString(type);
            
            if (moduleClass) {
                value = [moduleClass modelWithDict:value];
            }
        }
        
        // 三级转换: NSArray 中也是字典 把数组中的字典转化成模型
        if ([value isKindOfClass:[NSArray class]]) {
            // 判断对应类有没有实现字典数组转模型数组的协议
            if ([self respondsToSelector:@selector(arrayContainModelClass)]) {
                // 转换成id类型 就能调用任何对象的方法
                id idSelf = self;
                
                // 获取数组中字典对应的模型
                NSString *type = [idSelf arrayContainModelClass][key];
                //生成模型
                Class classModel = NSClassFromString(type);
                NSMutableArray *arrayM = [NSMutableArray array];
                // 遍历字典数组 生成模型数组
                for (NSDictionary *dict in value) {
                    // 字典模型
                    id model = [classModel modelWithDict:dict];
                    [arrayM addObject:model];
                }
                // 把模型数组赋值给value
                value = arrayM;
            }
            
            // 模型里面套模型
            if ([self respondsToSelector:@selector(modelContainModelClass)]) {
                id idSelf = self;
                NSString *type = [idSelf modelContainModelClass][key];
                Class classModel = NSClassFromString(type);
                NSMutableArray *arrayM = [NSMutableArray array];
                for (NSDictionary *dict in value) {
                    id model = [classModel modelWithDict:dict];
                    [arrayM addObject:model];
                }
                value = arrayM;
            }
        }
        if (value) {// 有值，才需要给模型的属性赋值
            // 利用KVC给模型的属性赋值
            [obj setValue:value forKey:key];
        }
    }
    return obj;
}

@end

使用 以请求豆瓣电影250为例

DouBanModel.h

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#import <Foundation/Foundation.h>
#import "NSObject+ModelExtension.h"

@interface MovieInfo : NSObject <NSCoding>

@property (nonatomic, strong)   NSDictionary *rating;
@property (nonatomic, assign)   NSInteger id;
@property (nonatomic, copy)     NSString  *original_title;
@property (nonatomic, assign)   NSInteger collect_count;
@property (nonatomic, copy)     NSArray *directors;
@property (nonatomic, copy)     NSString  *title;
@property (nonatomic, copy)     NSString  *year;
@property (nonatomic, copy)     NSArray *casts;
@property (nonatomic, copy)     NSArray *genres;
@property (nonatomic, strong)   NSDictionary *images;
@property (nonatomic, copy)     NSString  *subtype;
@property (nonatomic, copy)     NSString  *alt;

@end


@interface DouBanModel : NSObject <NSObjectDelegate, NSCoding>

@property (nonatomic, assign)   NSInteger count;
@property (nonatomic, assign)   NSInteger start;
@property (nonatomic, assign)   NSInteger total;
@property (nonatomic, copy)     NSString *title;
@property (nonatomic, strong)   NSArray<MovieInfo *> *subjects;

@end

DouBanModel.m

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@implementation DouBanModel
+ (NSDictionary *)modelContainModelClass {
    return @{@"subjects": NSStringFromClass([MovieInfo class])};
}
@end

ViewController.m 网络请求

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 [[NetWorkTooth shendeInstence] requestWithUrl:@"https://api.douban.com/v2/movie/top250?start=0&count=50" success:^(NSDictionary *dictData) {
 DouBanModel *model = [DouBanModel modelWithDict:dictData];
 [self saveData:model];	
NSLog(@"请求的到的:");
 for (MovieInfo *info in model.subjects) {
     NSLog(@"%@ - %@", info.title, info.year);
 }
} failed:^(NSError *error) {
 
}];

Demo 地址

https://github.com/GhostClock/Runtime-Demo

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面试题：你用过 performSelector 吗？

其实就是动态添加方法:

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RuntimeTest *test = [[RuntimeTest alloc] initWithLog:@"123"];
[test performSelector:@selector(printLog1:log2:) withObject:@"One" withObject:@"Two"]; // 动态添加方法
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+ (BOOL)resolveInstanceMethod:(SEL)sel {
    if (sel == @selector(printLog1:log2:)) {
        class_addMethod(self, @selector(printLog1:log2:), (IMP)printLog, "v@:@@");
    }
    return [super resolveInstanceMethod:sel];
}

void printLog(id self, SEL _cmd, NSString *log1, NSString *log2) {
    //TODO
}

Demo 地址

https://github.com/GhostClock/Runtime-Demo

Posted on

获取一个类的属性列表

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- (void)getPropertyList {
    unsigned int count;
    objc_property_t *propertys = class_copyPropertyList([self class], &count);
    for (int i = 0; i < count; i ++) {
        objc_property_t property = propertys[i];
        NSLog(@"%s %s\n", property_getName(property), property_getAttributes(property));
    }
    free(propertys);
}

获取一个类的方法列表

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- (void)getMethodList {
    unsigned int count;
    Method *methods = class_copyMethodList([self class], &count);
    for (int i = 0; i < count; i ++) {
        Method method = methods[i];
        NSLog(@"%@ %u \n", NSStringFromSelector(method_getName(method)), method_getNumberOfArguments(method));
    }
    free(methods);
}

获取成员变量

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- (void)getIvarList {
    unsigned int count;
    Ivar *ivars = class_copyIvarList([self class], &count);
    for (int i = 0; i < count; i ++) {
        Ivar ivar = ivars[i];
        NSLog(@"%s %s \n", ivar_getName(ivar), ivar_getTypeEncoding(ivar));
    }
    free(ivars);
}

获取协议名

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- (void)getProtocolList {
    unsigned int count;
    __unsafe_unretained Protocol **protocols = class_copyProtocolList([self class], &count);
    for (int i = 0; i < count; i ++) {
        NSLog(@"%s", protocol_getName(protocols[i]));
    }
    free(protocols);
}

Demo 地址

https://github.com/GhostClock/Runtime-Demo

Posted on

foundation 与 coreFoundation的桥接

1. 用__bridge桥接 NSArray -> CFArrayRef

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NSArray *fArray = @[@1, @2, @3, @4, @5];
// __bridge本身的意思是 ARC仍然具备这个OC对象的所有权, ARC任然会帮助我们释放
CFArrayRef cfArray = (__bridge CFArrayRef)fArray;
NSLog(@"Size of aray = %li", CFArrayGetCount(cfArray));

2. 用__bridge_retained 桥接 NSArray -> CFArrayRef

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// __bridge_retained 意味着ARC交出对象的所有权
cfArray = (__bridge_retained CFArrayRef)fArray;
NSLog(@"Size of aray = %li", CFArrayGetCount(cfArray));
CFRelease(cfArray); //手动释放内存

3. 用__bridge_transfer 桥接 CFArrayRef -> NSArray

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// 使ARC获得对象的所有权
fArray = (__bridge_transfer NSArray*)cfArray;

例子

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const void* RetainCallback(CFAllocatorRef allocator, const void* value) {
    return CFRetain(value);
}

void ReleaseCallback(CFAllocatorRef allocator, const void* value) {
    CFRelease(value);
}

CFDictionaryKeyCallBacks keyCallbacks = {
    0,
    RetainCallback,
    ReleaseCallback,
    NULL, //copyDescription取值为NULL,采用默认实现
    //equal和hash发布采用CFEqual和CFHash这二者采用的做法与NSMutableDictionary的默认实现相同
    CFEqual, // CFEqual最终会调用isEqual方法
    CFHash,
};

CFDictionaryValueCallBacks valueCallback = {
    0,
    RetainCallback,
    ReleaseCallback,
    NULL,
    CFEqual,
};
// 用CFMutableDictionaryRef来创建NSMutableDictionary
- (void)createMutableDictionaryForCFMutableDictionaryRef {
    CFMutableDictionaryRef aCFDicionary = CFDictionaryCreateMutable(NULL, 0, &keyCallbacks, &valueCallback);
    NSMutableDictionary *anNSDictionary = (__bridge_transfer NSMutableDictionary *)aCFDicionary;
    anNSDictionary[@"a"] = @123;
    [anNSDictionary removeObjectForKey:@"a"];
}

Posted on

Swift 创建栈(Stack)

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/// 栈
// 用数组作为栈的线性表的实现
public struct Stack<T> {
    // 数组
    fileprivate var stackArray = [T]()
    
    // count
    public var count: Int {
        return stackArray.count
    }
    
    // 是否为空
    public var isEmpty: Bool {
        return stackArray.isEmpty
    }
    
    // 顶部元素
    public var top: T? {
        guard !isEmpty else {
            return nil
        }
        return stackArray.last
    }
    
    // push 操作
    public mutating func push(_ element: T) {
        stackArray.append(element)
    }
    
    // pop 操作
    public mutating func pop() -> T? {
        guard !isEmpty else {
            print("stack is empty")
            return nil
        }
        return stackArray.removeLast()
    }
    
    // 打印所有元素
    public mutating func printAllElement() {
        guard count > 0 else {
            print("stack is empty")
            return
        }
        print("\npint all stack elements")
        for (index, value) in stackArray.enumerated() {
            print("[\(index)]\(value)")
        }
    }
}

使用栈

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var stack = Stack.init(stackArray: [])
stack.printAllElement()
stack.isEmpty

stack.push(22)
stack.printAllElement()

stack.push(33)
stack.printAllElement()

stack.top

stack.pop()
stack.printAllElement()

stack.pop()
stack.printAllElement()

stack.isEmpty