在iOS開(kāi)發(fā)中,需要把用戶(hù)的數(shù)據(jù)存儲(chǔ)起來(lái),便于下次使用,就需要用到數(shù)據(jù)存儲(chǔ)方法.

1.plist存儲(chǔ)

好處:可以手動(dòng)管理存儲(chǔ)路徑,避免系統(tǒng)刪除.

缺點(diǎn):存取都比較繁瑣,不能存儲(chǔ)對(duì)象.

存:

   //創(chuàng)建數(shù)據(jù)
   NSArray *arr = @[@123,@"dl"];
   //獲取存儲(chǔ)路徑
   NSString *path = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0];
  //給路徑加上擴(kuò)展名
  path = [path stringByAppendingPathComponent:@"arr.pilst"];
   //寫(xiě)入路徑
  [arr writeToFile:path atomically:YES];

取:

  //獲取存儲(chǔ)路徑
  NSString *path = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0];
  //給路徑加上擴(kuò)展名
  path = [path stringByAppendingPathComponent:@"arr.pilst"];
  //讀取文件
  [NSArray arrayWithContentsOfFile:path];

2.偏好設(shè)置存儲(chǔ)

好處:不需要關(guān)心存儲(chǔ)路徑.

缺點(diǎn):系統(tǒng)管理,程序猿無(wú)法手動(dòng)管理,不能存儲(chǔ)對(duì)象

存:

    //獲取系統(tǒng)對(duì)象
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    //存儲(chǔ)數(shù)據(jù)
    [defaults setObject:name forKey:@"name"];

** 取:**

    //定義屬性接收讀取的內(nèi)容
    NSString *name = [[NSUserDefaults standardUserDefaults] objectForKey:@"name"];

3.自定義對(duì)象存儲(chǔ)

好處:可以存儲(chǔ)任意內(nèi)容,且手動(dòng)管理路徑.

缺點(diǎn):需要實(shí)現(xiàn)很多方法,比較繁瑣.

存:

1.在點(diǎn)擊存儲(chǔ)時(shí)將數(shù)組數(shù)據(jù)歸檔存儲(chǔ):

    //使用自定義歸檔實(shí)現(xiàn)通訊錄內(nèi)容數(shù)據(jù)的存儲(chǔ)
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
    
    AddViewController *vc = segue.destinationViewController;
    
    vc.block = ^(DLContact *contact){
        
        [_contacts addObject:contact];
        //獲取路徑
        NSString *path = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0] stringByAppendingPathComponent:@"contact.data"];
        
        NSLog(@"%@",path);
        //歸檔內(nèi)容
        [NSKeyedArchiver  archiveRootObject:_contacts toFile:path];
        
        [self.tableView reloadData];
    };   
}

2.在模型類(lèi)中重寫(xiě)encodeWithCoder:和initWithCoder:方法給需要?dú)w檔和解檔的模型屬性設(shè)置歸檔和接檔

存取方法實(shí)現(xiàn):

//歸檔成員屬性并設(shè)置其對(duì)應(yīng)的key
- (void)encodeWithCoder:(NSCoder *)aCoder{
    
    [aCoder encodeObject:_name forKey:@"name"];
    [aCoder encodeObject:_phone forKey:@"phone"];
    
}
//根據(jù)key解檔數(shù)據(jù)并賦值給成員變量
- (instancetype)initWithCoder:(NSCoder *)aDecoder
    {//需先初始化父類(lèi)
    if (self = [super init]) {
        
        _name = [aDecoder decodeObjectForKey:@"name"];
        _phone = [aDecoder decodeObjectForKey:@"phone"];     
    }
    return self;
}

3.在數(shù)組懶加載方法中讀取解檔后的數(shù)據(jù)

取:

- (NSMutableArray *)contacts{
    //如果沒(méi)有值
    if (_contacts == nil) {
          //獲取存儲(chǔ)的路徑
          NSString *path = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0] stringByAppendingPathComponent:@"contact.data"];
          //給數(shù)組賦值
        _contacts = [NSKeyedUnarchiver unarchiveObjectWithFile:path];
         //如果解檔后無(wú)數(shù)據(jù)
        if (_contacts == nil) {
            //新建數(shù)組準(zhǔn)備存值
            _contacts = [NSMutableArray array];
        }   
    }
    return _contacts;
}

注意:如果對(duì)模型屬性進(jìn)行了編輯,需再次存檔之后才能讀取到新的模型數(shù)據(jù)!
Tips:可將存檔方法定義為block代碼塊方便及時(shí)調(diào)用.