为什么Realm＆＃34; to many＆＃34;关系总是有相同的参考？

Question

为什么领域列表包含相同的元素而不是不同的元素？

如下图所示，有两个relam-objects（UndoMemoryNameEntry和NameEntry）。第一个包含8个元素的列表。列表的元素类型是NameEntry！

类型

我的上一个NameEntry对象是用currentScorePlayer = 1和currentScoreMe = 15编写的，如下图所示：

UndoMemoryNameEntry中的列表正确插入了最后一个NameEntry对象。你会发现插入代码进一步向下...... 但现在问题是：为什么所有现有的list-elements都改为最新的插入元素????正如您在下图中所看到的，遗憾的是，所有元素都与最后添加的元素相同 - 为什么??????

如果我将NameEntry更改为以下内容：

在index = 0处插入列表，然后List更改为：

为什么所有的元素都改变了？而不只是插入一个???感谢您的帮助！

我的两个领域对象是：

class NameEntry: Object {
    dynamic var playerName = ""
    dynamic var isMyAdversary: Bool = false
    dynamic var currentScorePlayer: Int = 0
    dynamic var currentScoreMe: Int = 0
}

和列表：

class UndoMemoryNameEntry: Object {
    dynamic var undoPlayerName = ""
    let NameEntryList = List<NameEntry>()
}

以下代码创建了Realm-List：

// query rlm for existing object (with name adversary
let undoPredicate = NSPredicate(format: "undoPlayerName == %@", adversaryName)
let undoPlayerName = rlm.objects(UndoMemoryNameEntry).sorted("undoPlayerName", ascending: true).filter(undoPredicate)
// if undoPlayerName object does not exist - then create it!
if (undoPlayerName.count < 1) {
    rlm.beginWrite()
    let undoEntry = UndoMemoryNameEntry()
    undoEntry.undoPlayerName = adversaryName
    rlm.add(undoEntry)
    rlm.commitWrite()
}

以下代码在列表中添加＆＃34; NameEntry＆＃34; -Element：

let undoPredicate = NSPredicate(format: "undoPlayerName == %@", plaNameLab)
let undoPlayerName = rlm.objects(UndoMemoryNameEntry).sorted("undoPlayerName", ascending: true).filter(undoPredicate)
if (undoPlayerName.count == 1) {                    
    rlm.beginWrite()
    println(entry)
    var undoEntry = undoPlayerName[0] as UndoMemoryNameEntry
    undoEntry.NameEntryList.insert(entry, atIndex: 0)
    rlm.commitWrite()
}

上述代码异常完美 - 除了realm-List总是将其所有元素更改为刚刚插入的元素。

Answer 1

我终于找到了解决方案：

首先按如下方式重新排列两个领域对象：

class NameEntry: Object {
    dynamic var playerName = ""
    dynamic var currentScorePlayer: Int = 0
    dynamic var currentScoreMe: Int = 0

    // the undo-list is better placed in the first object...
    let undoEntryList = List<UndoMemoryNameEntry>()

    override static func primaryKey() -> String? {
        return "playerName"
    }
}

class UndoMemoryNameEntry: Object {
    dynamic var undoPlayerName = ""
    dynamic var currentScorePlayer: Int = 0
    dynamic var currentScoreMe: Int = 0

    // no primary key here since the undoEntry will have several items with the same undoPlayerName
}

然后在List中添加“NameEntry”-Element：

let predicate = NSPredicate(format: "playerName == %@", plaNameLab)
let playerName = rlm.objects(NameEntry).sorted("playerName", ascending: true).filter(predicate)
if (playerName.count == 1) {                    
    rlm.beginWrite()
    var entry = playerName[0] as NameEntry

    // you need to create a new list object first !!!!!!!!!!!!
    // ...in my initial example, this creation was missing !!!!!!
    var siblingEntry = UndoMemoryNameEntry()

    siblingEntry.undoPlayerName = plaNameLab
    siblingEntry.currentScorePlayer = entry.currentScorePlayer
    siblingEntry.currentScoreMe = entry.currentScoreMe

    // insert new list-element
    entry.undoEntryList.insert(siblingEntry, atIndex: 0)

    // alternatively choose append if you want to add the element at the end of the list
    entry.undoEntryList.append(siblingEntry)

    // or choose the "ringbuffer-solution" given in the add-on below if you want to restrict the number of list-elements to ringbuffer-size !
    // ...

    rlm.commitWrite()
}

加载项：如果要创建仅具有有限数量列表元素的环形缓冲区：

// create ringbuffer of 20 elements (20th element will be newest)
let ringBufferSize = 20
let undoPredicate = NSPredicate(format: "undoPlayerName == %@", plaNameLab)

if (entry.undoEntryList.filter(undoPredicate).sorted("undoPlayerName").count < ringBufferSize) {

    entry.undoEntryList.append(siblingEntry)
}
else {

    // entry.undoEntryList.replace(ringBufferSize-1, object: siblingEntry)
    entry.undoEntryList.removeAtIndex(ringBufferSize-1)
    entry.undoEntryList.append(siblingEntry)

    for index in 0..<ringBufferSize-1 {
        let tempEntry1 = rlm.objects(UndoMemoryNameEntry).filter(undoPredicate).sorted("undoPlayerName")[index] as UndoMemoryNameEntry
         let tempEntry2 = rlm.objects(UndoMemoryNameEntry).filter(undoPredicate).sorted("undoPlayerName")[index+1] as UndoMemoryNameEntry
         tempEntry1.currentScorePlayer = tempEntry2.currentScorePlayer
         tempEntry1.currentScoreMe = tempEntry2.currentScoreMe
     }

     let tempEntry = rlm.objects(UndoMemoryNameEntry).filter(undoPredicate).sorted("undoPlayerName")[ringBufferSize-1] as UndoMemoryNameEntry
     rlm.delete(tempEntry)
 }