【发布时间】：2021-09-06 00:10:09
【问题描述】：
我正在从 firebase 实时数据库中获取数据，并且在迭代 datasnapshot 时，当像这样将数据插入房间数据库时，我在第 493 行的行号处收到 java.util.concurrentmodificationexception at java.util.arraylist$itr.next 错误。
Inventory.getInstance(Inventory.this.getActivity(), 1).InventoryDAO().InsertData(items);
这是我得到这个错误的整个方法。
private List<InventoryEntity_TableColums> message; // Class Variable
private synchronized void append_inventory_conversation(DataSnapshot dataSnapshot) {
Iterator iterator = dataSnapshot.getChildren().iterator();
String inventory_Msg, inventory_TO, inventory_FROM, inventory_TimeStamp, inventory_FCM_FROM, inventory_FCM_TO, inventory_Type, Random_ID, inventory_FROM_ID, inventory_Receiver_ID;
while (iterator.hasNext()) {
inventory_Msg = (String) ((DataSnapshot) iterator.next()).getValue();
inventory_FROM = (String) ((DataSnapshot) iterator.next()).getValue();
inventory_FROM_ID = (String) ((DataSnapshot) iterator.next()).getValue();
inventory_TO = (String) ((DataSnapshot) iterator.next()).getValue();
inventory_TimeStamp = (String) ((DataSnapshot) iterator.next()).getValue();
inventory_Type = (String) ((DataSnapshot) iterator.next()).getValue();
Random_ID = (String) ((DataSnapshot) iterator.next()).getValue();
inventory_FCM_FROM = (String) ((DataSnapshot) iterator.next()).getValue();
inventory_FCM_TO = (String) ((DataSnapshot) iterator.next()).getValue();
// return count of RANDOM ID in room
int hasValue = inventoryRoomDatabase.getInstance(getActivity(), 1).inventoryDAO().CheckValueExist(Random_ID);
Log.d(TAG, "Has inventory " + hasValue);
if (hasValue == 0) {
inventoryEntity_TableColums inventoryEntity_tableColums;
if (inventory_Type.equals("1")) {
inventoryEntity_tableColums = new inventoryEntity_TableColums(Session.getUserID(),inventory_Msg, "1");
message.add(inventoryEntity_tableColums);
} else if (inventory_Type.equals("2")) {
inventoryEntity_tableColums = new inventoryEntity_TableColums(Session.getUserID(),inventory_Msg, "2");
message.add(inventoryEntity_tableColums);
} else if (inventory_Type.equals("3")) {
inventoryEntity_tableColums = new inventoryEntity_TableColums(Session.getUserID(),inventory_Msg, "3");
message.add(inventoryEntity_tableColums);
} else if (inventory_Type.equals("4")) { //THIS IS FOR SEARCHED IMAGES NOT FOR GIF IMAGES
inventoryEntity_tableColums = new inventoryEntity_TableColums( Session.getUserID(),inventory_Msg,"4");
message.add(inventoryEntity_tableColums);
} else if (inventory_Type.equals("5")) {
//Adding inventory Data Into Database
inventoryEntity_tableColums = new inventoryEntity_TableColums( Session.getUserID(),inventory_Msg,"5");
message.add(inventoryEntity_tableColums);
} else if (inventory_Type.equals("6")) {
//Adding inventory Data Into Database
inventoryEntity_tableColums = new inventoryEntity_TableColums( Session.getUserID(),inventory_Msg,"6");
message.add(inventoryEntity_tableColums);
} else if (inventory_Type.equals("7")) {
//Adding inventory Data Into Database
inventoryEntity_tableColums = new inventoryEntity_TableColums(Session.getUserID(),inventory_Msg,"7");
message.add(inventoryEntity_tableColums);
} else if (inventory_Type.equals("8")) {
//Adding inventory Data Into Database
inventoryEntity_tableColums = new inventoryEntity_TableColums( Session.getUserID(),inventory_Msg,"8");
message.add(inventoryEntity_tableColums);
} else if (inventory_Type.equals("9")) {
//Adding inventory Data Into Database
inventoryEntity_tableColums = new inventoryEntity_TableColums(Session.getUserID(),inventory_Msg,"9");
message.add(inventoryEntity_tableColums);
} else if (inventory_Type.equals("10")) {
//Adding inventory Data Into Database
inventoryEntity_tableColums = new inventoryEntity_TableColums( Session.getUserID(),inventory_Msg,"10");
message.add(inventoryEntity_tableColums);
} else if (inventory_Type.equals("11")) {
//Adding inventory Data Into Database
inventoryEntity_tableColums = new inventoryEntity_TableColums( Session.getUserID(),inventory_Msg,"11");
message.add(inventoryEntity_tableColums);
} else if (inventory_Type.equals("12")) {
inventoryEntity_tableColums = new inventoryEntity_TableColums( Session.getUserID(),inventory_Msg,"12");
message.add(inventoryEntity_tableColums);
Log.d(TAG, "Message Type Message" + inventory_Msg);
} else if (inventory_Type.equals("13")) {
inventoryEntity_tableColums = new inventoryEntity_TableColums( Session.getUserID(),inventory_Msg,"13");
message.add(inventoryEntity_tableColums);
}
}
}
new Thread(new Runnable() {
@Override
public void run() {
//THIS LINE WHERE I AM GETTING java.util.concurrentmodificationexception at java.util.arraylist$itr.next at insertInventory
inventoryRoomDatabase.getInstance(inventoryScreen.this.getActivity(), 1).inventoryDAO().Insertinventory(message);
}
}).start();
}
房间数据库的 InsertInventroy
@Insert(onConflict = OnConflictStrategy.IGNORE)
void Insertinventory(List<InventoryEntity_TableColums> inv);
【问题讨论】：
-
您的方法“insertInventory”看起来如何？
-
@Nemanja 请检查更新的问题
标签： java android loops iterator