iOS中自动实现对象序列化的方法详解

2020-07-26 02:49:45

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来源：转载

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前言

在iOS 中实现对象序列化，需要遵行NSCoding协议，然后对对象的每个属性进行归档和接档赋值，响应的操作比较繁琐。本文主要介绍利用 runtime遍历属性大大简化代码量，下面来看看详细的介绍吧。

具体实现代码如下:

1.先建立NSobject的分类, 定义可能用到的相关类型

static NSString *intType  = @"i"; // int_32t(枚举int型)static NSString *longTpye = @"l"; //long类型static NSString *longlongType= @"q"; // longlong类型static NSString *BoolType = @"B"; //bool类型static NSString *floatType = @"f"; // floatstatic NSString *doubleType = @"d"; // doublestatic NSString *boolType = @"c";static NSString *stringType = @"NSString"; // NSString 类型static NSString *numberType = @"NSNumber"; // NSNumber 类型static NSString *arrayType = @"arrayType";//array类型static NSString *imageType = @"UIImage"; // UIImage 类型

然后在归档方法中便利自身的属性名称，并且取出自身属性对应的值，进行存储到本地。此时遍历类属性本身，用到了Ivar指针（定义对象的实例变量，包括类型和名字），具体代码如下

//归档- (void)encodeWithCoder:(NSCoder *)aCoder{ unsigned int count; // 属性个数 Ivar *varArray = class_copyIvarList([self class], &count); for (int i = 0; i < count; i++) {  Ivar var = varArray[i];  const char *cName = ivar_getName(var); // 属性名c字符串  NSString *proName = [[NSString stringWithUTF8String:cName] substringFromIndex:1]; //OC字符串,并且去掉下划线 _  const char *cType = ivar_getTypeEncoding(var); // 获取变量类型，c字符串  id value = [self valueForKey:proName];  NSString *proType = [NSString stringWithUTF8String:cType]; // oc 字符串  if ([proType containsString:@"NSString"]) {   proType = stringType;  }  if ([proType containsString:@"NSNumber"]) {   proType = numberType;  }  if ([proType containsString:@"NSArray"]) {   proType = arrayType;  }  if ([proType containsString:@"UIImage"]) {   proType = imageType;  }  // (5). 根据类型进行编码  if ([proType isEqualToString:intType] || [proType isEqualToString:boolType] || [proType isEqualToString:BoolType]) {   [aCoder encodeInt32:[value intValue] forKey:proName];  }  else if ([proType isEqualToString:longTpye]) {   [aCoder encodeInt64:[value longValue] forKey:proName];  }  else if ([proType isEqualToString:floatType]) {   [aCoder encodeFloat:[value floatValue] forKey:proName];  }  else if ([proType isEqualToString:longlongType] || [proType isEqualToString:doubleType]) {   [aCoder encodeDouble:[value doubleValue] forKey:proName];  }  else if ([proType isEqualToString:stringType]) { // string 类型   [aCoder encodeObject:value forKey:proName];  }  else if ([proType isEqualToString:numberType]) {   [aCoder encodeObject:value forKey:proName];  }  else if ([proType isEqualToString:arrayType]) {   [aCoder encodeObject:value forKey:proName];  }  else if ([proType isEqualToString:imageType]) { // image 类型   [aCoder encodeDataObject:UIImagePNGRepresentation(value)];  } } free(varArray);}

其次进行解档，原理和归档差不多，直接上代码

- (instancetype)initWithCoder:(NSCoder *)aDecoder{ self = [self init]; if (self) {  unsigned int count;  Ivar *varArray = class_copyIvarList([self class], &count);  for (int i = 0; i < count; i++) {   Ivar var = varArray[i];   const char *cName = ivar_getName(var); // 属性名c字符串   NSString *proName = [[NSString stringWithUTF8String:cName] substringFromIndex:1]; //OC字符串,并且去掉下划线 _   const char *cType = ivar_getTypeEncoding(var); // 获取变量类型，c字符串   NSString *proType = [NSString stringWithUTF8String:cType]; // oc 字符串   if ([proType containsString:@"NSString"]) {    proType = stringType;   }   if ([proType containsString:@"NSNumber"]) {    proType = numberType;   }   if ([proType containsString:@"NSArray"]) {    proType = arrayType;   }   if ([proType containsString:@"UIImage"]) {    proType = imageType;   }   if ([proType isEqualToString:intType] || [proType isEqualToString:boolType] || [proType isEqualToString:BoolType]) {    int32_t number = [aDecoder decodeInt32ForKey:proName];    [self setValue:@(number) forKey:proName];   }   else if ([proType isEqualToString:longTpye]) {    int64_t number = [aDecoder decodeInt64ForKey:proName];    [self setValue:@(number) forKey:proName];   }   else if ([proType isEqualToString:floatType]) {    float number = [aDecoder decodeFloatForKey:proName];    [self setValue:@(number) forKey:proName];   }   else if ([proType isEqualToString:longlongType] || [proType isEqualToString:doubleType]) {    double number = [aDecoder decodeFloatForKey:proName];    [self setValue:@(number) forKey:proName];   }   else if ([proType isEqualToString:stringType]) { // string 类型    NSString *string = [aDecoder decodeObjectForKey:proName];    [self setValue:string forKey:proName];   }   else if ([proType isEqualToString:numberType]) {    NSString *number = [aDecoder decodeObjectForKey:proName];    [self setValue:number forKey:proName];   }   else if ([proType isEqualToString:arrayType]) {    NSArray *array = [aDecoder decodeObjectForKey:proName];    [self setValue:array forKey:proName];   }   else if ([proType isEqualToString:imageType]) { // image 类型    UIImage *image = [UIImage imageWithData:[aDecoder decodeDataObject]];    [self setValue:image forKey:proName];   }  } } return self;}

最后也就是存储方法、清除存储的本地缓存和获取本地存储数据的方法

//存储路径- (NSString *)filePathWithUniqueFlagString:(NSString *)uniqueFlag{ NSString *docPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject]; NSString *detailPath = [NSString stringWithFormat:@"%@_%@",uniqueFlag,[NSString stringWithUTF8String:object_getClassName(self)]]; NSString *path = [docPath stringByAppendingPathComponent:detailPath]; return path;}//保存对象数据到本地- (void)saveDataToLocalWithUniqueFlagKey:(NSString *)uniqueFlagKey{ [NSKeyedArchiver archiveRootObject:self toFile:[self filePathWithUniqueFlagString:uniqueFlagKey]];}//清空本地存储的对象数据- (id)getDataFromLocalWithUniqueFlagKey:(NSString *)uniqueFlagKey{ return [NSKeyedUnarchiver unarchiveObjectWithFile:[self filePathWithUniqueFlagString:uniqueFlagKey]];}//从本地获取对象数据- (BOOL)removeDataFromLocalWithUniqueFlagKey:(NSString *)uniqueFlagKey{ NSError *error = nil; [[NSFileManager defaultManager] removeItemAtPath:[self filePathWithUniqueFlagString:uniqueFlagKey] error:&error]; if (!error) {  return YES; } else {  return NO; }}

完整项目下载地址如下：https://github.com/maxzhang123/MXCoding.git 或者可以本地下载地址：http://xiazai.VeVB.COm/201705/yuanma/MXCoding(VeVB.COm).rar

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