我正在尝试构建一个聊天应用程序，但是每当我单击任何一个用户时，它就会崩溃。
class MessegeActivity : AppCompatActivity() {
var userIdVisit: String = ""
var currentUserId : FirebaseUser?=null
var chatsAdpater:ChatAdpater?=null
var mChatList:List<Chat>?=null
lateinit var recycler_view_chat:RecyclerView
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_messege)
intent = intent
userIdVisit = intent.getStringExtra("visit_id")
currentUserId =FirebaseAuth.getInstance().currentUser!!
recycler_view_chat =findViewById(R.id.recycler_view_chat)
recycler_view_chat.setHasFixedSize(true)
var linearLayoutManager =LinearLayoutManager(applicationContext)
linearLayoutManager.stackFromEnd =true
recycler_view_chat.layoutManager =linearLayoutManager
//showing other username and profile dp
val reference = FirebaseDatabase.getInstance().reference
.child("Users").child(userIdVisit)
reference.addValueEventListener(object : ValueEventListener {
override fun onDataChange(p0: DataSnapshot) {
val user: Users? = p0.getValue(Users::class.java)
username_mchat.text = user!!.getFullName()
Picasso.get().load(user.getImg()).into(profile_image_mchat)
retreiveMsg(currentUserId!!.uid,userIdVisit,user.getImg())
}
override fun onCancelled(error: DatabaseError) {
}
})
send_messege_btn.setOnClickListener {
val messege = text_messege.text.toString()
if (messege == "") {
Toast.makeText(this@MessegeActivity, "Please write something!!", Toast.LENGTH_SHORT)
.show()
} else {
sendMessegeToUser(currentUserId!!.uid, userIdVisit, messege)
}
text_messege.setText("")
}
attach_image_file.setOnClickListener {
val intent = Intent()
intent.action = Intent.ACTION_GET_CONTENT
intent.type = "image/*"
startActivityForResult(Intent.createChooser(intent, "Pick Image"), 198)
}
}
private fun sendMessegeToUser(senderId: String, receiverId: String?, messege: String) {
val reference = FirebaseDatabase.getInstance().reference
val messegeKey:String = reference.push().key!!
val messegeHashMap = HashMap<String, Any?>()
messegeHashMap["sender"] = senderId
messegeHashMap["messege"] = messege
messegeHashMap["receiver"] = receiverId
messegeHashMap["isseen"] = "false"
messegeHashMap["url"] = ""
messegeHashMap["messegeId"] = messegeKey
reference.child("Chats").child(messegeKey).setValue(messegeHashMap)
.addOnCompleteListener { task ->
if (task.isSuccessful) {
val ChatsListRefernce =
FirebaseDatabase.getInstance().reference.child("ChatLists").child(currentUserId!!.uid).child(userIdVisit)
ChatsListRefernce.addListenerForSingleValueEvent(object :ValueEventListener{
override fun onDataChange(p0: DataSnapshot) {
if(!p0.exists())
{
ChatsListRefernce.child("id").setValue(userIdVisit)
}
val ChatsListReceiverRefernce =
FirebaseDatabase.getInstance().reference.child("ChatLists").child(userIdVisit).child(currentUserId!!.uid)
ChatsListReceiverRefernce.child("id").setValue(currentUserId!!.uid)
}
override fun onCancelled(error: DatabaseError) {
}
})
//notification
// val reference = FirebaseDatabase.getInstance().reference
// .child("Users").child(currentUserId!!.uid)
}
}
}
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
super.onActivityResult(requestCode, resultCode, data)
if (requestCode == 198 && resultCode ==RESULT_OK && data!=null && data.data != null) {
val progressBar = ProgressDialog(this)
progressBar.setMessage("Please wait")
progressBar.show()
val fileUri = data.data
val storageRef = FirebaseStorage.getInstance().reference.child("Chat Images")
val ref = FirebaseDatabase.getInstance().reference
val messegeId = ref.push().key
val filepath = storageRef.child("$messegeId.jpg")
var uploadTask: StorageTask<*>
uploadTask = filepath.putFile(fileUri!!)
uploadTask.continueWithTask(Continuation<UploadTask.TaskSnapshot, Task<Uri>> { task ->
if (!task.isSuccessful) {
task.exception?.let {
throw it
}
}
return@Continuation filepath.downloadUrl
}).addOnCompleteListener { task ->
val downloadUrl = task.result
val url = downloadUrl.toString()
val messegeHashMap = HashMap<String,Any?>()
messegeHashMap["sender"] = currentUserId!!.uid
messegeHashMap["messege"] = "sent you an image"
messegeHashMap["receiver"] = userIdVisit
messegeHashMap["isseen"] = "false"
messegeHashMap["url"] = url
messegeHashMap["messegeId"] = messegeId.toString()
ref.child("Chats").child(messegeId!!).setValue(messegeHashMap)
progressBar.dismiss()
}
}
}
private fun retreiveMsg(senderId: String, receiverId: String?, recieverimgUrl: String?) {
mChatList =ArrayList()
val reference =FirebaseDatabase.getInstance().reference.child("Chats")
reference.addValueEventListener(object:ValueEventListener{
override fun onDataChange(p0: DataSnapshot) {
(mChatList as ArrayList<Chat>).clear()
for (snapshot in p0.children)
{
val chat= snapshot.getValue(Chat::class.java)
if(chat!!.getReceiver().equals(senderId)&& chat.getSender().equals(receiverId) ||
chat.getReceiver().equals(receiverId)&& chat.getSender().equals(senderId))
{
(mChatList as ArrayList<Chat>).add(chat)
}
chatsAdpater = ChatAdpater(this@MessegeActivity,(mChatList as ArrayList<Chat>),recieverimgUrl!!)
recycler_view_chat.adapter =chatsAdpater
}
}
override fun onCancelled(error: DatabaseError) {
TODO("Not yet implemented")
}
})
}
}
package com.insidecoderz.trails2.Model
class Chat {
private var sender:String =""
private var messege:String =""
private var receiver:String =""
private var isseen :Boolean= false
private var url:String =""
private var messegeId:String =""
constructor()
constructor(
sender: String,
messege: String,
receiver: String,
isseen:Boolean,
url: String,
messegeId: String
) {
this.sender = sender
this.messege = messege
this.receiver = receiver
this.isseen = isseen
this.url = url
this.messegeId = messegeId
}
fun getSender(): String?{
return sender
}
fun setSender(sender: String){
this.sender =sender
}
fun getMessege(): String?{
return messege
}
fun setMessege(messege: String){
this.messege =messege
}
fun getReceiver(): String?{
return receiver
}
fun setReceiver(receiver: String){
this.receiver =receiver
}
fun isIsSeen(): Boolean {
return isseen
}
fun setIsSeen(isseen: Boolean){
this.isseen =isseen
}
fun getUrl(): String?{
return url
}
fun setUrl(url: String){
this.url =url
}
fun getMessegeId(): String?{
return messegeId
}
fun setMessegeId(messegeId: String){
this.messegeId =messegeId
}
}
我一次又一次面对这个问题，每当我在模拟器中的应用程序中运行该应用程序时，它就会崩溃并显示此错误。
2020-08-22 23:19:59.920 17005-17005/com.insidecoderz.trails2 E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.insidecoderz.trails2, PID: 17005
com.google.firebase.database.DatabaseException: Can't convert object of type java.lang.Boolean to type com.insidecoderz.trails2.Model.Chat
at com.google.firebase.database.core.utilities.encoding.CustomClassMapper.convertBean(CustomClassMapper.java:435)
at com.google.firebase.database.core.utilities.encoding.CustomClassMapper.deserializeToClass(CustomClassMapper.java:231)
at com.google.firebase.database.core.utilities.encoding.CustomClassMapper.convertToCustomClass(CustomClassMapper.java:79)
at com.google.firebase.database.DataSnapshot.getValue(DataSnapshot.java:203)
at com.insidecoderz.trails2.MessegeActivity$retreiveMsg$1.onDataChange(MessegeActivity.kt:202)
at com.google.firebase.database.core.ValueEventRegistration.fireEvent(ValueEventRegistration.java:75)
at com.google.firebase.database.core.view.DataEvent.fire(DataEvent.java:63)
at com.google.firebase.database.core.view.EventRaiser$1.run(EventRaiser.java:55)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:224)
at android.app.ActivityThread.main(ActivityThread.java:7134)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:536)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:876)
答案 0 :(得分：3)
如果使用以下代码val reference = FirebaseDatabase.getInstance().reference.child("Users").child(userIdVisit)访问用户的ID，然后尝试将数据作为模型Chat获取，则不能这样做，而请尝试FirebaseDatabase.getInstance().reference.child("Users")。这样，您就可以将数据作为模型Chat获得，但它不是您想要的ID，如果在节点"Users"上您有更多的用户，那么您将获得所有使用模型Chat
如果您需要userIdVisit的信息，则可以执行以下操作
snapshot.child("userInfo1").getValue();
snapshot.child("userInfo2").getValue();
这是Java的示例，您应该将其改编为kotlin，很抱歉没有在kotlin中提供该示例，但我不熟悉