本文介绍了在FirebaseListAdapter中显示Firebase数据库内容的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我目前正在通过创建一种小型聊天应用程序来尝试使用Firebase.我能够将数据发送到数据库引用，但是由于以下代码，我希望它能显示出来.但是事实并非如此，我想知道我在列表中使用适配器的方式是否有问题.
I am currently experimenting with Firebase by creating a kind of small chat app.I am able to send data to the database reference, however I would expect it to be displayed thanks to the following code. However that is not the case, I was wondering if there was something wrong with the way I am using the adapter for my list.
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
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();
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 ChatMessage to the Firebase database
FirebaseDatabase.getInstance()
.getReference()
.push()
.setValue(new ChatMessage(input.getText().toString(),
FirebaseAuth.getInstance()
.getCurrentUser()
.getDisplayName())
);
// Clear the input
input.setText("");
}
});
}
private void displayChatMessages() {
ListView listOfMessages = (ListView)findViewById(R.id.list_of_messages);
Query query = FirebaseDatabase.getInstance().getReference();
FirebaseListOptions<ChatMessage> options = new FirebaseListOptions.Builder<ChatMessage>()
.setQuery(query, ChatMessage.class)
.setLayout(R.layout.message)
.build();
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 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);
}
@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();
}
}
}
}
这是主要活动的用户界面
Here is the UI of the main activity
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="citroentrex.citron.MainActivity">
<android.support.design.widget.FloatingActionButton
android:id="@+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
android:clickable="true"
android:tint="@android:color/white"
app:fabSize="mini"
/>
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_toLeftOf="@id/fab"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true">
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Input"
android:id="@+id/input"
/>
</android.support.design.widget.TextInputLayout>
<ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:dividerHeight="16dp"
android:divider="@android:color/transparent"
android:layout_above="@id/fab"
android:id="@+id/list_of_messages"
android:layout_marginBottom="16dp"
/>
</RelativeLayout>
和消息
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:id="@+id/message_user"
android:textStyle="normal|bold" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/message_user"
android:layout_alignParentRight="true"
android:id="@+id/message_time" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/message_user"
android:layout_alignParentLeft="true"
android:layout_marginTop="5dp"
android:id="@+id/message_text"
android:textAppearance="@style/TextAppearance.AppCompat.Body1"
android:textSize="18sp" />
</RelativeLayout>
displayChatMessages是我希望适配器显示列表中数据内容的地方. (将数据推送到数据库肯定可以正常工作)这是我的数据库模型. (没有孩子)
displayChatMessages is the bit wher I would expect the adapter to display the data content in my list. (Pushing data to the database works for sure)This is the model of my database. (there are no child)
推荐答案
适配器必须初始化如下:
The adapter had to be initialised as follow:
@Override
protected void onStart() {
super.onStart();
adapter.startListening();
}
@Override
protected void onStop() {
super.onStop();
adapter.stopListening();
}
这篇关于在FirebaseListAdapter中显示Firebase数据库内容的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！