首先说下我的需求:在A控制器,我有一个可变的自定义模型数组, 我要跳转到B控制器进行编辑的时候,我传入该模型数组.在B控制器我进行编辑,然后保存的时候把编辑后的数组逆传回去
刚开始,没觉得哪里不对,后来发现在B控制器只要我改动了原来的数据,即使不点击保存,而是直接pop掉B控制器返回A控制器,我的模型数据还是会被改变,原因是我在编辑界面是直接拿着传入的模型数组对象进行编辑,所以,要想"保存"与"取消"分开,就不能直接拿着传入的模型数组对象进行编辑. 这个时候我们要做的是深拷贝一份数据出来
在Objective-C中并不是所有的类都支持拷贝；只有遵循NSCopying协议的类，才支持copy拷贝，只有遵循NSMutableCopying协议的类，才支持mutableCopy拷贝。如果没有遵循拷贝协议，拷贝时会出错
如果我们想再我们自定义的类中支持copy和mutableCopy那么我们就需要使我们定义的类遵循NSCopying和NSMutableCopying协议, 然后再重写-(id) copyWithZone : (NSZone *) zone 和 -(id)mutableCopyWithZone : (NSZone *) zone
#import "SkuKeepingModel.h" @interface SkuKeepingModel ()<NSCopying,NSMutableCopying>
@implementation SkuKeepingModel
- (id)copyWithZone:(NSZone *)zone { SkuKeepingModel *newModel = [[self class] allocWithZone:zone]; newModel.keepingid = _keepingid; newModel.productid = _productid; newModel.reftable = _reftable; newModel.refrecordid = _refrecordid; newModel.keepingname = _keepingname; newModel.portrait = _portrait; newModel.quantity = _quantity; newModel.marketprice = _marketprice; newModel.discountprice = _discountprice; newModel.uunitprice = _uunitprice; newModel.soldcount = _soldcount; newModel.recordstatus = _recordstatus; newModel.createdate = _createdate; newModel.modifydate = _modifydate; return newModel; } - (id)mutableCopyWithZone:(NSZone *)zone { SkuKeepingModel *newModel = [[self class] allocWithZone:zone]; newModel.keepingid = _keepingid; newModel.productid = _productid; newModel.reftable = _reftable; newModel.refrecordid = _refrecordid; newModel.keepingname = _keepingname; newModel.portrait = _portrait; newModel.quantity = _quantity; newModel.marketprice = _marketprice; newModel.discountprice = _discountprice; newModel.uunitprice = _uunitprice; newModel.soldcount = _soldcount; newModel.recordstatus = _recordstatus; newModel.createdate = _createdate; newModel.modifydate = _modifydate; return newModel; }在B控制器弄个 属性来拷贝传入的模型数组
@property (strong, nonatomic) NSMutableArray <SkuKeepingModel *> *tempSkuKeepingModels;数组一传入B控制器马上进行拷贝 (是连容器内的元素也进行拷贝的哦)
SMutableArray *tempArr = [[NSMutableArray alloc] initWithArray:self.skuKeepingModels copyItems:YES]; self.tempSkuKeepingModels = tempArr;然后,你在该控制器拿的是拷贝后的另外一个对象进行编辑了
其实利用归档解档的操作也可以实现完全拷贝,
NSData *data = [NSKeyedArchiver archivedDataWithRootObject:self.skuKeepingModels]; NSMutableArray *newArray = [NSKeyedUnarchiver unarchiveObjectWithData:data];当然了,前提条件是你重写了这两个方法
- (id) initWithCoder: (NSCoder *)coder - (void) encodeWithCoder: (NSCoder *)coder- (id) initWithCoder: (NSCoder *)coder { if (self = [super init]) { self.keepingid = [coder decodeObjectForKey:@"keepingid"]; self.productid = [coder decodeObjectForKey:@"productid"]; . . . . } return self; } - (void) encodeWithCoder: (NSCoder *)coder { [coder encodeObject:self.keepingid forKey:@"keepingid"]; [coder encodeObject:self.productid forKey:@"productid"]; . . . . }
这里顺便说下,数据库返回的字段经常都会直接有 id 命名的 因为id是关键字 碰到这种情况我要进行key的替换 比如我们重命名为_id
- (void)setValue:(id)value forUndefinedKey:(NSString *)key { if ([key isEqualToString:@"id"]) { self._id = value; } }
转载于:https://www.cnblogs.com/yulongjiayuan/p/6101810.html
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