iOS 自動實現對象序列化方法

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iOS 中對象序列化，需要遵行NSCoding協議，然後對對象的每個屬性進行歸檔和接檔賦值，響應的操作比較繁瑣。本文主要介紹 利用 runtime遍曆屬性 大大簡化代碼量

具體實現代碼如下:
1.先建立NSobject的分類, 定義可能用到的相互關聯類型

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

然後在歸檔方法中便利自身的屬性名稱，並且取出自身屬性對應的值，進行儲存到本地。此時遍曆類屬性本身，用到了Ivar指標（定義對象的執行個體變數，包括類型和名字），具體代碼如下

//歸檔- (void)encodeWithCoder:(NSCoder *)aCoder{    unsigned int count; // 屬性個數    Ivar *varArray = class_copyIvarList([self class], &count);    for (int i = 0; i < count; i++)    {        Ivar var = varArray[i];        const char *cName = ivar_getName(var); // 屬性名稱c字串        NSString *proName = [[NSString stringWithUTF8String:cName] substringFromIndex:1]; //OC字串,並且去掉底線 _        const char *cType = ivar_getTypeEncoding(var); // 擷取變數類型，c字串        id value = [self valueForKey:proName];        NSString *proType = [NSString stringWithUTF8String:cType]; // oc 字串        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). 根據類型進行編碼        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 類型            [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 類型            [aCoder encodeDataObject:UIImagePNGRepresentation(value)];        }    }    free(varArray);}

其次進行解檔， 原理和歸檔差不多， 直接上代碼

- (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); // 屬性名稱c字串            NSString *proName = [[NSString stringWithUTF8String:cName] substringFromIndex:1]; //OC字串,並且去掉底線 _            const char *cType = ivar_getTypeEncoding(var); // 擷取變數類型，c字串            NSString *proType = [NSString stringWithUTF8String:cType]; // oc 字串            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 類型                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 類型                UIImage *image = [UIImage imageWithData:[aDecoder decodeDataObject]];                [self setValue:image forKey:proName];            }        }    }    return self;}

最後也就是 儲存方法 、 清除儲存的本機快取 和 擷取本機存放區資料的方法

//儲存路徑- (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;}//儲存對象資料到本地- (void)saveDataToLocalWithUniqueFlagKey:(NSString *)uniqueFlagKey{    [NSKeyedArchiver archiveRootObject:self toFile:[self filePathWithUniqueFlagString:uniqueFlagKey]];}//清空本機存放區的對象資料- (id)getDataFromLocalWithUniqueFlagKey:(NSString *)uniqueFlagKey{    return [NSKeyedUnarchiver unarchiveObjectWithFile:[self filePathWithUniqueFlagString:uniqueFlagKey]];}//從本地擷取對象資料- (BOOL)removeDataFromLocalWithUniqueFlagKey:(NSString *)uniqueFlagKey{    NSError *error = nil;    [[NSFileManager defaultManager] removeItemAtPath:[self filePathWithUniqueFlagString:uniqueFlagKey] error:&error];    if (!error) {        return YES;    }    else {        return NO;    }}

完整項目如下：https://github.com/maxzhang123/MXCoding.git

轉載請註明 出處，謝謝

iOS 自動實現對象序列化方法