您好我正在创建一个基于Firebase和Parse的聊天应用程序。在此我提到官方Firebase聊天示例。聊天工作正常，但来电和发送聊天都是一个接一个地显示。像这样，例如
作者：发件人
消息：你好
作者：接收人
消息：你好吗？
我只需要聊天看起来像左右对齐的应用和其他聊天。
在firebase聊天中，他们使用两个适配器，一个是FirebaseListAdapter（通用，它扩展了BaseAdapter），另一个是ChatListAdapter（扩展了FirebaseCahtListAdapter）。我不知道修改代码的位置。请帮我解决这个问题。
FirebaseListAdapter
public abstract class FirebaseListAdapter<T> extends BaseAdapter {
private Query mRef;
private Class<T> mModelClass;
private int mLayout;
private LayoutInflater mInflater, recieveInflater;
private List<T> mModels;
private Map<String, T> mModelKeys;
private ChildEventListener mListener;
/**
* @param mRef The Firebase location to watch for data changes. Can also be a slice of a location, using some
* combination of <code>limit()</code>, <code>startAt()</code>, and <code>endAt()</code>,
* @param mModelClass Firebase will marshall the data at a location into an instance of a class that you provide
* @param mLayout This is the mLayout used to represent a single list item. You will be responsible for populating an
* instance of the corresponding view with the data from an instance of mModelClass.
* @param activity The activity containing the ListView
*/
public FirebaseListAdapter(Query mRef, Class<T> mModelClass, int mLayout, Activity activity) {
this.mRef = mRef;
this.mModelClass = mModelClass;
this.mLayout = mLayout;
mInflater = activity.getLayoutInflater();
mModels = new ArrayList<T>();
mModelKeys = new HashMap<String, T>();
// Look for all child events. We will then map them to our own internal ArrayList, which backs ListView
mListener = this.mRef.addChildEventListener(new ChildEventListener() {
@Override
public void onChildAdded(DataSnapshot dataSnapshot, String previousChildName) {
T model = dataSnapshot.getValue(FirebaseListAdapter.this.mModelClass);
mModelKeys.put(dataSnapshot.getKey(), model);
// Insert into the correct location, based on previousChildName
if (previousChildName == null) {
mModels.add(0, model);
} else {
T previousModel = mModelKeys.get(previousChildName);
int previousIndex = mModels.indexOf(previousModel);
int nextIndex = previousIndex + 1;
if (nextIndex == mModels.size()) {
mModels.add(model);
} else {
mModels.add(nextIndex, model);
}
}
notifyDataSetChanged();
}
@Override
public void onChildChanged(DataSnapshot dataSnapshot, String s) {
// One of the mModels changed. Replace it in our list and name mapping
String modelName = dataSnapshot.getKey();
T oldModel = mModelKeys.get(modelName);
T newModel = dataSnapshot.getValue(FirebaseListAdapter.this.mModelClass);
int index = mModels.indexOf(oldModel);
mModels.set(index, newModel);
mModelKeys.put(modelName, newModel);
notifyDataSetChanged();
}
@Override
public void onChildRemoved(DataSnapshot dataSnapshot) {
// A model was removed from the list. Remove it from our list and the name mapping
String modelName = dataSnapshot.getKey();
T oldModel = mModelKeys.get(modelName);
mModels.remove(oldModel);
mModelKeys.remove(modelName);
notifyDataSetChanged();
}
@Override
public void onChildMoved(DataSnapshot dataSnapshot, String previousChildName) {
// A model changed position in the list. Update our list accordingly
String modelName = dataSnapshot.getKey();
T oldModel = mModelKeys.get(modelName);
T newModel = dataSnapshot.getValue(FirebaseListAdapter.this.mModelClass);
int index = mModels.indexOf(oldModel);
mModels.remove(index);
if (previousChildName == null) {
mModels.add(0, newModel);
} else {
T previousModel = mModelKeys.get(previousChildName);
int previousIndex = mModels.indexOf(previousModel);
int nextIndex = previousIndex + 1;
if (nextIndex == mModels.size()) {
mModels.add(newModel);
} else {
mModels.add(nextIndex, newModel);
}
}
notifyDataSetChanged();
}
@Override
public void onCancelled(FirebaseError firebaseError) {
Log.e("FirebaseListAdapter", "Listen was cancelled, no more updates will occur");
}
});
}
public void cleanup() {
// We're being destroyed, let go of our mListener and forget about all of the mModels
mRef.removeEventListener(mListener);
mModels.clear();
mModelKeys.clear();
}
@Override
public int getCount() {
return mModels.size();
}
@Override
public Object getItem(int i) {
return mModels.get(i);
}
@Override
public long getItemId(int i) {
return i;
}
@Override
public View getView(int i, View view, ViewGroup viewGroup) {
if (view == null) {
view = mInflater.inflate(mLayout, viewGroup, false);
}
T model = mModels.get(i);
// Call out to subclass to marshall this model into the provided view
populateView(view, model);
return view;
}
/**
* Each time the data at the given Firebase location changes, this method will be called for each item that needs
* to be displayed. The arguments correspond to the mLayout and mModelClass given to the constructor of this class.
* <p/>
* Your implementation should populate the view using the data contained in the model.
*
* @param v The view to populate
* @param model The object containing the data used to populate the view
*/
protected abstract void populateView(View v, T model);
}
ChatListAdapter
public class ChatListAdapter extends FirebaseListAdapter<Chat> {
// The mUsername for this client. We use this to indicate which messages originated from this user
private String mUsername;
Activity activity;
LayoutInflater inflater;
public ChatListAdapter(Query ref, Activity activity, int layout, String mUsername) {
super(ref, Chat.class, layout, activity);
this.mUsername = mUsername;
this.activity = activity;
this.inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
/**
* Bind an instance of the <code>Chat</code> class to our view. This method is called by <code>FirebaseListAdapter</code>
* when there is a data change, and we are given an instance of a View that corresponds to the layout that we passed
* to the constructor, as well as a single <code>Chat</code> instance that represents the current data to bind.
*
* @param view A view instance corresponding to the layout we passed to the constructor.
* @param chat An instance representing the current state of a chat message
*/
@Override
protected void populateView(View view, Chat chat) {
String author = chat.getAuthor();
TextView authorText = (TextView) view.findViewById(R.id.author);
TextView messageText = (TextView) view.findViewById(R.id.message);
authorText.setText(author + ": ");
// If the message was sent by this user, design it differently
if (author != null && author.equals(mUsername)) {
authorText.setTextColor(view.getResources().getColor(R.color.lblFromName));
authorText.setGravity(Gravity.RIGHT | Gravity.END);
messageText.setText(chat.getMessage());
messageText.setGravity(Gravity.RIGHT);
messageText.setBackground(view.getResources().getDrawable(R.drawable.bg_msg_you));
} else {
authorText.setTextColor(view.getResources().getColor(R.color.lblFromName));
authorText.setGravity(Gravity.LEFT | Gravity.START);
messageText.setText(chat.getMessage());
messageText.setGravity(Gravity.LEFT);
messageText.setBackground(view.getResources().getDrawable(R.drawable.bg_msg_from));
}
}
}
CahtListAdapter中使用的布局文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:orientation="vertical">
<TextView
android:id="@+id/author"
android:layout_width="wrap_content"
android:text="Name"
android:padding="5dp"
android:textStyle="italic"
android:textSize="12dp"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/message"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Content"
android:paddingBottom="5dp"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:paddingTop="5dp"
android:textSize="16dp"
android:layout_marginLeft="5dp"
android:layout_marginRight="5dp"/>
</LinearLayout>
答案 0 :(得分：1)
布局文件：
LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="wrap_content"
android:layout_width="match_parent"
android:orientation="vertical">
<TextView
android:id="@+id/author"
android:layout_width="wrap_content"
android:text="Name"
android:padding="5dp"
android:textStyle="italic"
android:textSize="12dp"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/message"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Content"
android:paddingBottom="5dp"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:paddingTop="5dp"
android:textSize="16dp"
android:layout_marginLeft="5dp"
android:layout_marginRight="5dp"/>
LinearLayout>
在适配器文件中
<TextView
android:id="@+id/author"
android:layout_width="wrap_content"
android:text="Name"
android:padding="5dp"
android:textStyle="italic"
android:textSize="12dp"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/message"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Content"
android:paddingBottom="5dp"
android:paddingLeft="10dp"
android:paddingRight="10dp"
android:paddingTop="5dp"
android:textSize="16dp"
android:layout_marginLeft="5dp"
android:layout_marginRight="5dp"/>
答案 1 :(得分：1)
最后我找到了一个解决方案，我刚刚在编码中添加了一个LayoutGravity，并从那里设置了Gravity。
在ChatListAdapter中
@Override
protected void populateView(View view, Chat chat) {
String author = chat.getAuthor();
TextView authorText = (TextView) view.findViewById(R.id.author);
TextView messageText = (TextView) view.findViewById(R.id.message);
authorText.setText(author + ": ");
// If the message was sent by this user, design it differently
if (author != null && author.equals(mUsername)) {
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.FILL_PARENT);
params.weight = 1.0f;
params.gravity = Gravity.RIGHT;
authorText.setTextColor(view.getResources().getColor(R.color.lblFromName));
authorText.setLayoutParams(params);
messageText.setText(chat.getMessage());
messageText.setBackground(view.getResources().getDrawable(R.drawable.bg_msg_you));
messageText.setLayoutParams(params);
} else {
authorText.setTextColor(view.getResources().getColor(R.color.lblFromName));
authorText.setGravity(Gravity.LEFT | Gravity.START);
messageText.setText(chat.getMessage());
messageText.setGravity(Gravity.LEFT);
messageText.setBackground(view.getResources().getDrawable(R.drawable.bg_msg_from));
}
}