[英]How to get Username of Specific User from Firebase?
我正在 android 中制作一個群聊應用程序,其中數據庫是 Firebase 實時數據庫。
在注冊用戶時,我成功地將用戶的“用戶名”和“電子郵件”保存在 Firebase 的“用戶”節點中。
問題是如何在他/她發布消息時隨聊天一起獲取特定人名?
這是我的注冊活動,當新用戶注冊時,我在數據庫中保存了“用戶名”和“電子郵件”:
FirebaseAuth mAuth;
mAuth = FirebaseAuth.getInstance();
private void DOSignup() {
final String get_name = name.getText().toString().trim();
final String get_email = email.getText().toString().trim();
String get_password = password.getText().toString().trim();
mAuth.createUserWithEmailAndPassword(get_email, get_password).addOnCompleteListener(new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
if (task.isSuccessful()) {
FirebaseUser firebaseUser = mAuth.getCurrentUser();
Log.e("Current User", firebaseUser.toString());
DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference().child("Users");
GetUserName getUserName = new GetUserName(get_name, get_email);
String id = databaseReference.push().getKey();
databaseReference.child(id).setValue(getUserName);
Toast.makeText(getApplicationContext(), "Registration successful!", Toast.LENGTH_LONG).show();
Intent intent = new Intent(SignUpActivity.this, LoginActivity.class);
startActivity(intent);
} else {
Toast.makeText(getApplicationContext(), "Registration failed! Please try again later", Toast.LENGTH_LONG).show();
}
}
});
這是用戶發布消息的方式:
private void postMessages() {
databaseReference = FirebaseDatabase.getInstance().getReference("MessageTest");
Log.e("Reference is : ", String.valueOf(databaseReference));
String actual_msg = editText.getText().toString().trim();
ChatModel chatModel = new ChatModel(actual_msg);
String id = databaseReference.push().getKey();
databaseReference.child(id).setValue(chatModel).addOnCompleteListener(new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
if (task.isSuccessful()) {
Toast.makeText(ChatActivity.this, "Message Sent Successfully", Toast.LENGTH_SHORT).show();
editText.setText("");
} else {
Toast.makeText(ChatActivity.this, "Message Sent Failed !", Toast.LENGTH_SHORT).show();
}
}
});
}
這是我的 ChatModel 類:
public class ChatModel {
String messages;
public ChatModel() {
}
public ChatModel(String messages) {
this.messages = messages;
}
public String getMessages() {
return messages;
}
}
這是我的 ChatAdapter 類,其中向用戶顯示消息:
public class ChatAdapter extends FirebaseRecyclerAdapter<ChatModel, ChatAdapter.ViewHolder> {
Context context;
List<ChatModel> chatModelList;
public ChatAdapter(@NonNull FirebaseRecyclerOptions<ChatModel> options, Context context, List<ChatModel> chatModelList) {
super(options);
this.context = context;
this.chatModelList = chatModelList;
}
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.chat_layout,
parent, false);
return new ViewHolder(view);
}
@Override
protected void onBindViewHolder(@NonNull ViewHolder holder, int position, @NonNull ChatModel model) {
ChatModel model1 = chatModelList.get(position);
GetUserName getUserName = new GetUserName();
DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference();
holder.messages.setText();
holder.userName.setText(databaseReference.getKey());
}
class ViewHolder extends RecyclerView.ViewHolder {
TextView messages,userName;
public ViewHolder(@NonNull View itemView) {
super(itemView);
messages = itemView.findViewById(R.id.message_body);
userName = itemView.findViewById(R.id.userName); //This is a TextView where usernames need to be shown
}
}
首先,我強烈建議您稍微更改存儲用戶數據的結構。 您現在正在使用push()
生成唯一鍵。 但是由於每個用戶已經有一個唯一的 UID,您可以將用戶存儲在該 UID 下並使其更容易查找。 要將其存儲在此結構中:
DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference().child("Users");
GetUserName getUserName = new GetUserName(get_name, get_email);
String uid = FirebaseAuth.getInstance().getCurrentUser().getUid();
databaseReference.child(uid).setValue(getUserName);
有了這個,讓我們在將消息寫入數據庫時使用用戶名。
您需要在應用啟動並登錄時加載當前用戶的名稱。代碼如下所示:
if (FirebaseAuth.getInstance().getCurrentUser() != null) {
String uid = FirebaseAuth.getInstance().getCurrentUser().getUid();
DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference().child("Users");
DatabaseReference userReference = databaseReference.child(uid);
userReference.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
userName = dataSnapshot.child("UserName").getValue(String.class);
}
@Override
public void onCancelled(DatabaseError databaseError) {
throw databaseError.toException();
}
}
}
在上面的代碼片段中, userName
是您活動類的成員字段,因此您也可以在其他地方訪問它。
此代碼運行后,您可以通過以下方式將用戶名寫入消息:
ChatModel
類ChatModel
實例時,設置使用代碼片段加載的用戶名。
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