Question

在尝试使用firebase执行简单的聊天应用程序时，我遇到了下面记录的此错误。我注意到的一件事是，之前的消息将加载，但我尝试刷到最后一条消息的实例，然后应用程序崩溃，同时给出下面的日志。我将真诚地感谢帮助了解其原因。感谢

com.google.firebase.database.DatabaseException：无法转换对象类型为java.util.ArrayList，用于键入chat.ChatMessage 在com.google.android.gms.internal.zzamy.zze（未知来源）在com.google.android.gms.internal.zzamy.zzb（未知来源）在com.google.android.gms.internal.zzamy.zza（未知来源）在com.google.firebase.database.DataSnapshot.getValue（未知来源）在 com.firebase.ui.database.FirebaseListAdapter.parseSnapshot（FirebaseListAdapter.java:120）在 com.firebase.ui.database.FirebaseListAdapter.getItem（FirebaseListAdapter.java:109）在 com.firebase.ui.database.FirebaseListAdapter.getView（FirebaseListAdapter.java:137）在android.widget.AbsListView.obtainView（AbsListView.java:2485）在android.widget.ListView.makeAndAddView（ListView.java:1945）在android.widget.ListView.fillDown（ListView.java:710）在android.widget.ListView.fillGap（ListView.java:674）在android.widget.AbsListView.trackMotionScroll（AbsListView.java:5534）在android.widget.AbsListView $ FlingRunnable.run（AbsListView.java:5030）在 android.view.Choreographer $ CallbackRecord.run（Choreographer.java:800）在android.view.Choreographer.doCallbacks（Choreographer.java:603）在android.view.Choreographer.doFrame（Choreographer.java:571）在 android.view.Choreographer $ FrameDisplayEventReceiver.run（Choreographer.java:786）在android.os.Handler.handleCallback（Handler.java:815）在android.os.Handler.dispatchMessage（Handler.java:104）在android.os.Looper.loop（Looper.java:194）在android.app.ActivityThread.main（ActivityThread.java:5682） at java.lang.reflect.Method.invoke（Native Method）在java.lang.reflect.Method.invoke（Method.java:372）在 com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:963）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:758）

这是我正在使用的ChatMessage模型

public class ChatMessage {

    private String messageText;
    private String messageUser;
    private long messageTime;

    public ChatMessage(String messageText, String messageUser) {
        this.messageText = messageText;
        this.messageUser = messageUser;
        messageTime = new Date().getTime();
    }

    public ChatMessage(){

    }

    public String getMessageText() {
        return messageText;
    }

    public void setMessageText(String messageText) {
        this.messageText = messageText;
    }

    public String getMessageUser() {
        return messageUser;
    }

    public void setMessageUser(String messageUser) {
        this.messageUser = messageUser;
    }

    public long getMessageTime() {
        return messageTime;
    }

    public void setMessageTime(long messageTime) {
        this.messageTime = messageTime;
    }
}

我的displayChat消息是

private void displayChatMessages() throws DatabaseException {
        ListView listOfMessages = (ListView)findViewById(R.id.list_of_messages);
try{
        adapter = new FirebaseListAdapter<ChatMessage>(this, ChatMessage.class,
                R.layout.message_activity, FirebaseDatabase.getInstance().getReference()) {
            @Override
            protected void populateView(View v, ChatMessage model, int position) {
                // Get references to the views of message.xml
                TextView messageText = (TextView)v.findViewById(R.id.message_text);
                TextView messageUser = (TextView)v.findViewById(R.id.message_user);
                TextView messageTime = (TextView)v.findViewById(R.id.message_time);

                // Set their text
                messageText.setText(model.getMessageText());
                messageUser.setText(model.getMessageUser());
                messageTime.setText(DateFormat.format("dd-MM-yyyy (HH:mm:ss)",
                        model.getMessageTime()));
            }
        };

        listOfMessages.setAdapter(adapter);
    }catch (DatabaseException ex){
    ex.printStackTrace();
    }}

无法将ArrayList类型的对象转换为我的模型

0 个答案: