我正在使用Firebase制作一个Android聊天应用程序...我的代码中没有任何错误，应用程序可以编译。但是当我去测试它时，输入的文本根本没有显示......
我遵循的原始教程对私有 void displayChatMessages(( 的代码略有不同，但它显示错误，所以我更改了代码。
旧代码还有其他一些行，例如：
ListView listOfMessages = (ListView(findViewById(R.id.list_of_messages(;listOfMessages.setAdapter(adapter(;
我想我可能需要输入类似上面的东西，但我无法得到它。
任何帮助将不胜感激，因为我似乎无法弄清楚！
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();
}
}
}
}
通过将
单个消息的布局从相对布局更改为线性布局来解决发送消息后不显示消息的问题
<?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>