Android Studio和Firebase-聊天应用程序不显示输入的文本

Question

I'm making an Android chat app using Firebase... I don't have any errors in my code and the app compiles. However when I go to test it, the inputted text is not displaying at all ...

The original tutorial I was following had slightly different code for private void displayChatMessages() but it was showing errors so I changed the code.

The old code had some other lines like:

ListView listOfMessages = (ListView)findViewById(R.id.list_of_messages); listOfMessages.setAdapter(adapter);

And I think I may need to put in something like the above but I can't get it.

Any help would be appreciated as I cannot seem to figure it out!

package com.josephine.projectv3;

import android.content.Intent;
import android.support.annotation.NonNull;
import android.support.design.widget.FloatingActionButton;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.format.DateFormat;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import com.firebase.ui.auth.AuthUI;
import com.firebase.ui.database.FirebaseListAdapter;
import com.firebase.ui.database.FirebaseListOptions;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.Query;

public class Chat extends AppCompatActivity {

    private static final int SIGN_IN_REQUEST_CODE = 1;
    private FirebaseListAdapter<ChatMessage> adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_chat);


        if(FirebaseAuth.getInstance().getCurrentUser() == null) {
            // Start sign in/sign up activity
            startActivityForResult(
                    AuthUI.getInstance()
                            .createSignInIntentBuilder()
                            .build(),
                    SIGN_IN_REQUEST_CODE
            );
        } else {
            // User is already signed in. Therefore, display
            // a welcome Toast
            Toast.makeText(this,
                    "Welcome " + FirebaseAuth.getInstance()
                            .getCurrentUser()
                            .getDisplayName(),
                    Toast.LENGTH_LONG)
                    .show();

            // Load chat room contents
            displayChatMessages();
        }
        FloatingActionButton fab =
                (FloatingActionButton)findViewById(R.id.fab);

        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                EditText input = (EditText)findViewById(R.id.input);

                // Read the input field and push a new instance
                // of com.josephine.projectv3.ChatMessage to the Firebase database
                FirebaseDatabase.getInstance()
                        .getReference()
                        .push()
                        .setValue(new ChatMessage(input.getText().toString(),
                                FirebaseAuth.getInstance()
                                        .getCurrentUser()
                                        .getDisplayName())
                        );

                // Clear the input
                input.setText("");
            }
        });

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main_menu, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if(item.getItemId() == R.id.menu_sign_out) {
            AuthUI.getInstance().signOut(this)
                    .addOnCompleteListener(new OnCompleteListener<Void>() {
                        @Override
                        public void onComplete(@NonNull Task<Void> task) {
                            Toast.makeText(Chat.this,
                                    "You have been signed out.",
                                    Toast.LENGTH_LONG)
                                    .show();

                            // Close activity
                            finish();
                        }
                    });
        }
        return true;
    }
    private void displayChatMessages() {

        //Suppose you want to retrieve "chats" in your Firebase DB:
        Query query = FirebaseDatabase.getInstance().getReference().child("chats");
//The error said the constructor expected FirebaseListOptions - here you create them:
        FirebaseListOptions<ChatMessage> options = new FirebaseListOptions.Builder<ChatMessage>()
                .setQuery(query, ChatMessage.class)
                .setLayout(R.layout.message)
                .build();
        //Finally you pass them to the constructor here:

        adapter = new FirebaseListAdapter<ChatMessage>(options){
            @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 messageTime = (TextView)v.findViewById(R.id.message_time);
                TextView messageUser = (TextView)v.findViewById(R.id.message_user);

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

    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode,
                                    Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if(requestCode == SIGN_IN_REQUEST_CODE) {
            if(resultCode == RESULT_OK) {
                Toast.makeText(this,
                        "Successfully signed in. Welcome!",
                        Toast.LENGTH_LONG)
                        .show();
                displayChatMessages();
            } else {
                Toast.makeText(this,
                        "We couldn't sign you in. Please try again later.",
                        Toast.LENGTH_LONG)
                        .show();

                // Close the app
                finish();
            }
        }

    }
}

Answer 1

problem of not showing message after sending them its is solved by changing layout of individual message from relative to linear layout

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:weightSum="1.0">
        <TextView
            android:layout_width="0dp"
            android:layout_weight="0.5"
            android:layout_height="wrap_content"
            android:id="@+id/message_user"
            android:textStyle="normal|bold"/>
        <TextView
            android:layout_width="0dp"
            android:layout_weight="0.5"
            android:layout_height="wrap_content"
            android:id="@+id/message_time"
            android:textStyle="normal|bold"/>
    </LinearLayout>
    <TextView
        android:layout_marginTop="5dp"
        android:layout_width="wrap_content"
        android:textSize="18sp"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/message_user"
        android:layout_alignParentEnd="true"
        android:textAppearance="@style/TextAppearance.AppCompat.Body1"
        android:id="@+id/message_text"
        android:textStyle="normal|bold"/>

</LinearLayout>