0
私は自分でアンドロイドを学習している学生です。 これは私の最初の質問です。私を助けてください。com.google.firebase.database.DatabaseException：java.lang.String型のオブジェクトを変換できません
09-12 01:35:35.723 2355-2355/com.example.jan.sanhakproject E/AndroidRuntime:
FATAL EXCEPTION: main
Process: com.example.jan.sanhakproject, PID: 2355
com.google.firebase.database.DatabaseException: Can't convert object of type java.lang.String to type com.example.jan.sanhakproject.Chat
at com.google.android.gms.internal.zzbqi.zze(Unknown Source)
at com.google.android.gms.internal.zzbqi.zzb(Unknown Source)
at com.google.android.gms.internal.zzbqi.zza(Unknown Source)
at com.google.firebase.database.DataSnapshot.getValue(Unknown Source)
at com.example.jan.sanhakproject.ChatActivity$2.onChildAdded(ChatActivity.java:115)
at com.google.android.gms.internal.zzblz.zza(Unknown Source)
at com.google.android.gms.internal.zzbnz.zzYj(Unknown Source)
at com.google.android.gms.internal.zzboc$1.run(Unknown Source)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)
09-12 01:35:44.318 2355-2374/com.example.jan.sanhakproject W/DynamiteModule: Local module descriptor class for com.google.firebase.auth not found.
Chat.java
パブリッククラスチャット{
public String email;
public String text;
public Chat() {
// Default constructor required for calls to DataSnapshot.getValue(Comment.class)
}
public Chat(String text) {
this.text = text;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getText() {
return text;
}
public void setText(String text) {
this.text = text;
}
}
ChatActivity.java
public class ChatActivity extends AppCompatActivity {
String TAG = this.getClass().getSimpleName();
private DatabaseReference mDatabase;
private FirebaseDatabase firebaseDatabase;
private RecyclerView mRecyclerView;
private RecyclerView.Adapter mAdapter;
private RecyclerView.LayoutManager mLayoutManager;
String[] myDataset = {"안녕", "오늘","뭐했어","영화볼래?"};
DatabaseReference databaseReference;
EditText etText;
Button btnSend;
String email;
List<Chat> mChat;
FirebaseDatabase database;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_chat);
firebaseDatabase = FirebaseDatabase.getInstance();
databaseReference = firebaseDatabase.getReference();
//database = FirebaseDatabase.getInstance();
FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
if (user != null) {
// Name, email address, and profile photo Url
email = user.getEmail();
}
Intent in = getIntent();
final String stChatId = in.getStringExtra("friendUid");
etText = (EditText) findViewById(R.id.etText);
btnSend = (Button) findViewById(R.id.btnSend);
btnSend.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String stText = etText.getText().toString();
if (stText.equals("") || stText.isEmpty()) {
Toast.makeText(ChatActivity.this, "내용을 입력해 주세요.", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(ChatActivity.this, email + "," + stText, Toast.LENGTH_SHORT).show();
Calendar c = Calendar.getInstance();
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String formattedDate = df.format(c.getTime());
databaseReference = database.getReference("users").child(stChatId).child(formattedDate);
Hashtable<String, String> chat = new Hashtable<String, String>();
chat.put("email", email);
chat.put("text", stText);
databaseReference.setValue(chat);
etText.setText("");
}
}
});
mRecyclerView = (RecyclerView) findViewById(R.id.my_recycler_view);
// use this setting to improve performance if you know that changes
// in content do not change the layout size of the RecyclerView
mRecyclerView.setHasFixedSize(true);
// use a linear layout manager
mLayoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLayoutManager);
mChat = new ArrayList<>();
// specify an adapter (see also next example)
mAdapter = new MyAdapter(mChat, email, ChatActivity.this);
mRecyclerView.setAdapter(mAdapter);
databaseReference.child("users").child(stChatId).child("chats").addChildEventListener(new ChildEventListener() {
@Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
Chat chat = dataSnapshot.getValue(Chat.class);
mChat.add(chat);
mRecyclerView.scrollToPosition(mChat.size() - 1);
mAdapter.notifyItemInserted(mChat.size() - 1);
}
@Override
public void onChildChanged(DataSnapshot dataSnapshot, String s) {
}
@Override
public void onChildRemoved(DataSnapshot dataSnapshot) {
}
@Override
public void onChildMoved(DataSnapshot dataSnapshot, String s) {
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
}
MyAdapter.java
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
private String[] mDataset;
List<Chat> mChat;
String stEmail;
Context context;
// Provide a reference to the views for each data item
// Complex data items may need more than one view per item, and
// you provide access to all the views for a data item in a view holder public static class ViewHolder extends RecyclerView.ViewHolder {
// each data item is just a string in this case
public TextView mTextView;
public ViewHolder(View itemView) {
super(itemView);
mTextView = (TextView) itemView.findViewById(R.id.mTextView);
}
}
// Provide a suitable constructor (depends on the kind of dataset)
public MyAdapter(List<Chat> mChat, String email, Context context) {
this.mChat = mChat;
this.stEmail = email;
this.context = context;
}
@Override
public int getItemViewType(int position) {
if (mChat.get(position).getEmail().equals(stEmail)){
return 1;
} else {
return 2;
}
}
// Create new views (invoked by the layout manager)
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent,
int viewType) {
// create a new view
View v;
if (viewType == 1) {
v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.right_text_view, parent, false);
} else {
v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.my_text_view, parent, false);
}
// set the view's size, margins, paddings and layout parameters
ViewHolder vh = new ViewHolder(v);
return vh;
}
// Replace the contents of a view (invoked by the layout manager)
@Override
public void onBindViewHolder(ViewHolder holder, final int position) {
// - get element from your dataset at this position
// - replace the contents of the view with that element
holder.mTextView.setText(mChat.get(position).getText());
holder.mTextView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Toast.makeText(context, String.valueOf(position), Toast.LENGTH_SHORT).show();
}
});
}
// Return the size of your dataset (invoked by the layout manager)
@Override
public int getItemCount() {
return mChat.size();
}
}
あなたの問題を指定してください、あなたはそのエラーを取得しなかった理由であなたがで新しいチャットのために聞いているように見えます。私たちは問題を読むために十分な時間がないので、直接指定してコードを単純化しなければならないので、エラーとの関連がないコードを投稿する必要はありません。 – Deee
チャットアプリをリアルタイムで作成したいのですが、データを受信する過程で、データを取得していることを確認したいと思います。 原因：java。遅れ。 NullPointe rException：挨拶に「失敗」と一致しない エラーが生成されます。 すみません。 –
null値を持つオブジェクト参照を使用しようとしています。またはnull参照によって参照されるオブジェクトのインスタンスメソッドを呼び出すことができます。 – Deee