用nsuserdefaults和手机重启后的load保存数据是行不通的

Question

我设法保存NSMutableArray在NSUserDefaults首先转换为NSData -我不处理大量的数据，只是希望数据在我关闭&在我的手机上-但数据没有显示在我的表中，我将显示它。我在加载时将NSUserDefaults写回我的数组。也许你们有人能给点提示…?在按钮操作下面，我写入NSUserDefaults和viewDidLoad方法，我将NSUserDefaults写入原始数组(toDoitems)

- (IBAction)unwindToList:(UIStoryboardSegue *)segue
{
    XYZAddToDoItemViewController *source = [segue sourceViewController];
    XYZToDoItem *item = source.toDoItem;
     if (item !=nil) {
        [self.toDoitems addObject:item];
        NSString *error;
        NSData *data = [NSPropertyListSerialization dataFromPropertyList:self.toDoitems format:NSPropertyListBinaryFormat_v1_0 errorDescription:&error];
        [[NSUserDefaults standardUserDefaults] setObject:data forKey:@"itemArray"];
        [[NSUserDefaults standardUserDefaults] synchronize];
        [self.tableView reloadData];
    }
}
- (void)viewDidLoad
{
    [super viewDidLoad];
    self.toDoitems = [[NSMutableArray alloc] init];
    self.toDoitems = [NSMutableArray arrayWithArray:[[NSUserDefaults standardUserDefaults] objectForKey:@"itemArray"]];
}

Answer 1

有一种方法可以做到这一点

1. 将编码器解码器功能添加到XYZToDoItem类中比如这个类中有两个字符串string1和string2(我没有编译这段代码，但你得到的想法)

   -(void)encodeWithCoder:(NSCoder *)aCoder
   {
   [aCoder encodeObject:self.string1 forKey:@"string1"];
   [aCoder encodeObject:self.string2 forKey:@"string2"];
    }
   -(id)initWithCoder:(NSCoder *)aDecoder
   {
   self = [super init];
   if (self) 
   {
       self.string1 = [aDecoder decodeObjectForKey:@"string1"];
       self.string2 = [aDecoder decodeObjectForKey:@"string2"];
   }
   return self;
   }
   

2. 当您准备保存时，执行以下操作

   NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
   NSData *data = [NSKeyedArchiver archivedDataWithRootObject:self.myDataArray];
   [userDefaults setObject:data forKey:@"storageName"];
   // To load the data from NSUserDefaults
   NSData *myData = [[NSUserDefaults standardUserDefaults] objectForKey:@"storageName"];
   NSArray *temp = (NSMutableArray*)[NSKeyedUnarchiver unarchiveObjectWithData:myData];
   self.myDataArray =  (NSMutableArray*)[temp mutableCopy];