我正在使用 Android Studio 創建一個聊天程式，但我無法找到一種方法來顯示訊息串列，這些訊息串列為傳入訊息左對齊，為傳出訊息右對齊。現在，它們都是左對齊的。
根據用戶 ID 是否與當前登錄的用戶 ID 相同，左右對齊文本的最簡單方法是什么？下面是它現在的樣子。
當前串列視圖示例
uj5u.com熱心網友回復：
假設您為此應用程式使用 Firebase 并獲取當前登錄的用戶詳細資訊，您可以對 Adapter 類（本示例中的 MessageAdapter）進行一些更改。
歸功于我曾經在我的應用程式中執行此操作的大量 youtube 視頻和在線資源
- 為 2 個不同的用戶創建 chat_item_right.xml 和 chat_item_left.xml
- 在 MessageAdapter 類中進行一些更改
public class MessageAdapter extends RecyclerView.Adapter<MessageAdapter.MyViewHolder> {
public static final int MSG_TYPE_LEFT = 0;
public static final int MSG_TYPE_RIGHT = 1;
private Context mContext;
private List<Chat> mChat;
private String imageurl;
private FirebaseUser firebaseUser;
public MessageAdapter(Context mContext, List<Chat> mChat, String imageurl) {
this.mContext = mContext;
this.mChat = mChat;
this.imageurl = imageurl;
firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
}
@NonNull
@Override
public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
// Get the view type and create the right view
View view;
if (viewType == MSG_TYPE_RIGHT) {
view = LayoutInflater.from(mContext).inflate(R.layout.chat_item_right, parent, false);
}
else {
view = LayoutInflater.from(mContext).inflate(R.layout.chat_item_left, parent, false);
}
return new MyViewHolder(view);
}
// Method to get each chat message and show it
@Override
public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {
Chat chat = mChat.get(position);
if (imageurl.equals("default")) {
holder.profile_image.setImageResource(R.mipmap.ic_launcher);
}
else {
Glide.with(mContext).load(imageurl).into(holder.profile_image);
}
if (chat.getType().equals("text")) {
holder.show_message.setText(chat.getMessage());
}
else if (chat.getType().equals("image")) {
// Depends on your code here
Glide.with(mContext).load(chat.getMessage()).into(holder.image_message);
}
}
@Override
public int getItemCount() {
return mChat.size();
}
public class MyViewHolder extends RecyclerView.ViewHolder {
private TextView show_message, txt_seen;
private ImageView profile_image, image_message;
public MyViewHolder(@NonNull View itemView) {
super(itemView);
show_message = itemView.findViewById(R.id.show_message);
profile_image = itemView.findViewById(R.id.profile_image);
txt_seen = itemView.findViewById(R.id.txt_seen);
image_message = itemView.findViewById(R.id.image_message);
}
}
@Override
public int getItemViewType(int position) {
// If i'm the sender show message on right else show it on left
if (mChat.get(position).getSender().equals(firebaseUser.getUid())) {
return MSG_TYPE_RIGHT;
}
else {
return MSG_TYPE_LEFT;
}
}
}
- 在 MessageActivity 或 Fragment 類中呼叫它
private MessageAdapter messageAdapter;
private List<Chat> mChat;
private DatabaseReference reference;
private FirebaseUser firebaseUser;
private String userid;
. // All your relevant code here
.
.
firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
// You should have stored the current user the moment you have logged in
// in SharedPrefs perhaps (or DataStore or etc) so that we can compare later
// during set view_item to left or right
// For e.g sending the userID as bundle from Login Page to MessageActivity
// intent = new Intent(this, MessageActivity.class);
// bundle.putString("userid", user);
userid = intent.getStringExtra("userid");
private void readMessages(final String myId, final String userid, final String imageurl) {
mChat = new ArrayList<>();
reference = FirebaseDatabase.getInstance().getReference("Chats");
reference.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
mChat.clear();
for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
Chat chat = snapshot.getValue(Chat.class);
// Add to chat list only messages between you and the sender
assert chat != null;
// The below code depends on your Chat object class
// So please modify accordingly
if (chat.getReceiver() != null && chat.getSender() != null) {
if (chat.getReceiver().equals(myId) && chat.getSender().equals(userid) ||
chat.getReceiver().equals(userid) && chat.getSender().equals(myId)) {
mChat.add(chat);
}
}
}
// Create a new adapter and set it to our view
messageAdapter = new MessageAdapter(MessageActivity.this, mChat, imageurl);
recyclerView.setAdapter(messageAdapter);
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
}
// Call the function
readMessages(firebaseUser.getUid(), userid, user.getImageURL());
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