Android 正在尝试设置Firebase聊天消息的侦听器
我正在尝试为Firebase设置一个侦听器,以获取新的聊天消息并将其发送到片段中的回收器视图,但我一直收到两个错误: 第一个错误出现在setupAdapter中的“数据”上,第二个错误出现在message.timestamp上 类型不匹配:Android 正在尝试设置Firebase聊天消息的侦听器,android,firebase,firebase-realtime-database,kotlin,Android,Firebase,Firebase Realtime Database,Kotlin,我正在尝试为Firebase设置一个侦听器,以获取新的聊天消息并将其发送到片段中的回收器视图,但我一直收到两个错误: 第一个错误出现在setupAdapter中的“数据”上,第二个错误出现在message.timestamp上 类型不匹配: Required: kotlin.collections.ArrayList<com.ntx_deisgns.cyberchatter.cyberchatter.Message> /* = java.util.ArrayList<com.n
Required:
kotlin.collections.ArrayList<com.ntx_deisgns.cyberchatter.cyberchatter.Message> /* = java.util.ArrayList<com.ntx_deisgns.cyberchatter.cyberchatter.Message> */
Found:
kotlin.collections.ArrayList<android.os.Message> /* = java.util.ArrayList<android.os.Message> */
下面是我的片段类中的代码:
private fun createFirebaseListener(){
val postListener = object : ValueEventListener {
override fun onDataChange(dataSnapshot: DataSnapshot) {
val toReturn: ArrayList<Message> = ArrayList();
for(data in dataSnapshot.children){
val messageData = data.getValue<Message>(Message::class.java)
//unwrap
val message = messageData?.let { it } ?: continue
toReturn.add(message)
}
//sort so newest at bottom
toReturn.sortBy { message ->
message.timestamp
}
setupAdapter(toReturn)
}
override fun onCancelled(databaseError: DatabaseError) {
//log error
}
}
val database = FirebaseDatabase.getInstance()
val myRef = database.getReference("message")
val mDatabase: DatabaseReference? = myRef
mDatabase?.child("Group Chat")?.addValueEventListener(postListener)
}
/**
* Once data is here - display it
*/
private fun setupAdapter(data: ArrayList<Message>){
val linearLayoutManager = LinearLayoutManager(context)
viewManager = LinearLayoutManager(context)
viewAdapter = MessageAdapter(data) {
// Toast.makeText(this, "${it.text} clicked", Toast.LENGTH_SHORT).show()
}
//scroll to bottom
mainActivityRecyclerView.scrollToPosition(data.size - 1)
}
我原以为这将是一项相当简单和直接的任务,但结果并不像我想象的那么简单。我在这里到底遗漏了什么,使我无法正确执行此操作?我导入了android.os.Message,它导入了错误的类。我只需要导入com.ntx_deisgns.cyberchatter.cyberchatter.Message就可以导入我的Message类。问题已解决。您在“类导入”部分引用了错误的消息类。android.os.Message而不是com.ntx_deisgns.cyberchatter.cyberchatter.Message我指的是
viewAdapter=MessageAdapter(Data)
的“数据”和消息的“时间戳”。请添加您在此类中使用的导入语句
private fun createFirebaseListener(){
val postListener = object : ValueEventListener {
override fun onDataChange(dataSnapshot: DataSnapshot) {
val toReturn: ArrayList<Message> = ArrayList();
for(data in dataSnapshot.children){
val messageData = data.getValue<Message>(Message::class.java)
//unwrap
val message = messageData?.let { it } ?: continue
toReturn.add(message)
}
//sort so newest at bottom
toReturn.sortBy { message ->
message.timestamp
}
setupAdapter(toReturn)
}
override fun onCancelled(databaseError: DatabaseError) {
//log error
}
}
val database = FirebaseDatabase.getInstance()
val myRef = database.getReference("message")
val mDatabase: DatabaseReference? = myRef
mDatabase?.child("Group Chat")?.addValueEventListener(postListener)
}
/**
* Once data is here - display it
*/
private fun setupAdapter(data: ArrayList<Message>){
val linearLayoutManager = LinearLayoutManager(context)
viewManager = LinearLayoutManager(context)
viewAdapter = MessageAdapter(data) {
// Toast.makeText(this, "${it.text} clicked", Toast.LENGTH_SHORT).show()
}
//scroll to bottom
mainActivityRecyclerView.scrollToPosition(data.size - 1)
}
class Message {
constructor() //empty for firebase
constructor(messageText: String){
text = messageText
}
var text: String? = null
var timestamp: Long = System.currentTimeMillis()
}