java - 如何为多个列表创建一个条件，仅显示具有相同值的数组

Question

我想在多个数组中设置一个条件，以获取仅包含“已交付”的数组列表。有人可以帮我解决这个问题吗？

我已经尝试过“myOrderItemModelList.contains("Delivered")”，但我总是得到空白结果。

    List<MyOrderItemModel> myOrderItemModelList = new ArrayList<>();

    myOrderItemModelList.add(new MyOrderItemModel(R.drawable.tide_prod, 2, "Tide Detergent", "149.50", "Ren's Grocery", "Juan Dela cruz", "Order_Received", 4, 3));
    myOrderItemModelList.add(new MyOrderItemModel(R.drawable.tide_prod, 2, "Tide Detergent", "149.75", "Ren's Grocery", "Juan Dela cruz", "On_Process", 0, 5));
    myOrderItemModelList.add(new MyOrderItemModel(R.drawable.tide_prod, 3, "Tide Detergent", "50", "Ren's Grocery", "Juan Dela cruz", "Order_Processed", 1, 0));
    myOrderItemModelList.add(new MyOrderItemModel(R.drawable.tide_prod, 1, "Tide Detergent", "70", "Ren's Grocery", "Juan Dela cruz", "On_Delivery", 1, 1));
    myOrderItemModelList.add(new MyOrderItemModel(R.drawable.tide_prod, 5, "Tide Detergent", "30", "Ren's Grocery", "Juan Dela cruz", "Delivered", 3, 2));
    myOrderItemModelList.add(new MyOrderItemModel(R.drawable.tide_prod, 6, "Tide Detergent", "56", "Ren's Grocery", "Juan Dela cruz", "Delivered", 2, 4));
    myOrderItemModelList.add(new MyOrderItemModel(R.drawable.tide_prod, 1, "Tide Detergent", "75", "Ren's Grocery", "Juan Dela cruz", "Cancelled", 5, 2));

    if (myOrderItemModelList.contains("Delivered")) {
        MyOrderItemOnProcessAdapter myOrderItemOnProcessAdapter = new MyOrderItemOnProcessAdapter(myOrderItemModelList);
        my_orders_recyclerview.setAdapter(myOrderItemOnProcessAdapter);
        myOrderItemOnProcessAdapter.notifyDataSetChanged();
    }

Answer 1

myOrderItemModelList.contains("Delivered") 不会给您想要的东西，因为您的列表包含 MyOrderItemModel 实例，而不是字符串。

如果您正在寻找仅包含状态为“已交付”的项目的过滤列表，则情况如下，假设 MyOrderItemModel 上有一个 status() 方法:

List<MyOrderItemModel> delivered = myOrderItemModelList.stream().filter( 
  item -> "Delivered".equals(item.status())).collect(Collectors.toList());

或者，如果您想对整个列表执行某些操作，但前提是至少有一项具有“已送达”状态:

if (myOrderItemModelList.stream().anyMatch(item -> "Delivered".equals(item.status()))) {
      MyOrderItemOnProcessAdapter myOrderItemOnProcessAdapter = new 
      MyOrderItemOnProcessAdapter(myOrderItemModelList);
      my_orders_recyclerview.setAdapter(myOrderItemOnProcessAdapter);
      myOrderItemOnProcessAdapter.notifyDataSetChanged();           
}