Firebase实时数据库无法正常工作，setValue

Question

我是通过教程制作的 ＆＃39; https://firebase.google.com/docs/database/android/start/?hl=ko＆＃39;用于Firebase实时数据库

但我在onDataChanged＆＃39; EventValueListner＆＃39;

之后看不到任何数据

你能解释一下为什么吗？

FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference myRef = database.getReference("message");

myRef.setValue("Hello, World!");
// Read from the database
myRef.addValueEventListener(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        // This method is called once with the initial value and again
        // whenever data at this location is updated.
        String value = dataSnapshot.getValue(String.class);
        Log.d("TAG", "Value is: " + value);
    }

   @Override
    public void onCancelled(DatabaseError error) {
        // Failed to read value
        Log.w("TAG", "Failed to read value.", error.toException());
    }
});

这是我的代码。

我的错是什么？

Answer 1

此示例将在firebase db中插入新用户数据。

 FirebaseDatabase database;
    DatabaseReference usersTable;
    database = FirebaseDatabase.getInstance();
    usersTable = database.getReference("Users");
    /*we work here */
    usersTable.addValueEventListener(new ValueEventListener() {
                    @Override
                    public void onDataChange(DataSnapshot dataSnapshot) {

                        progressDialog.dismiss();
                        if (dataSnapshot.child(phoneEditText.getText().toString()).exists()) {

                            Toast.makeText(SignUp.this, "Number already register", Toast.LENGTH_SHORT).show();
                        }else{
                            Users users = new Users(nameEditText.getText().toString(),passwordEditTex.getText().toString(),phoneEditText.getText().toString());
                            usersTable.child(phoneEditText.getText().toString()).setValue(users);
                            Toast.makeText(SignUp.this, "Signup Sucessfully", Toast.LENGTH_SHORT).show();
                            finish();
                        }


                    }

                    @Override
                    public void onCancelled(DatabaseError databaseError) {

                    }
                });

希望这会对你有所帮助