我想过滤 Firebase 数据并仅在 kotlin 的 recyclerview 上显示通过电子邮件过滤的用户

Question

我的 RecyclerViewActivity 上有这个功能，它可以获取 Firebase 存储中的所有数据

  private fun fetchData() {
       FirebaseFirestore.getInstance().collection("users")
           .get()
           .addOnSuccessListener { documents ->
               for (document in documents){
                   val user = documents.toObjects(User::class.java)
                   // I want to display only users with a determinate email
                   rvUsers.adapter = UserAdapter(this, user)
               }
           }
           .addOnFailureListener {
               Toast.makeText(this, "Error RecyclerViewActivity", Toast.LENGTH_LONG).show()
           }
   }
}

这是我的用户类

data class User ( var email: String = "",
                  var uid: String = "",
                  var restaurant: String = "",
                  var rating: String = "",
                  var imageUrl: String = ""
                )```
I would like to display only some users on the recyclerview, those are users filtered by email, but I don't know how to do it. Is was triying something like this ```user.equals(email)``` but dind't work. If anyone could help me please

Answer 1

有两种方法可以回答您的问题：

1. 如果您在进行任何获取之前已经有了过滤器，我强烈建议您进行查询以获取您需要的数据。无需获取所有集合。

2. 如果您要在获取所有数据后过滤您的集合，那么我建议将您的数据存储在应用程序中的某个位置，然后如果您没有任何过滤器，请将整个集合传递给 RV，否则，通过过滤后的列表。

请让我确切地知道您想提供更多信息。