Question

我正在尝试使用以下代码：

DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference productsRef = rootRef.child("products");
ValueEventListener eventListener = new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        for(DataSnapshot ds : dataSnapshot.getChildren()) {
            String product = ds.getKey();
            Log.d("TAG", product);
        }
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {}
};
productsRef.addListenerForSingleValueEvent(eventListener);

但是我遇到了这些错误：

Undefined class DatabaseReference
Undefined class FirebaseDatabase
Undefined class DataSnapshot

等等。

在build.gradle（app）内部，我有以下实现：

dependencies {
...
    implementation 'com.google.firebase:firebase-core:16.0.7'
    implementation 'com.google.firebase:firebase-database:16.0.6'
    implementation 'com.google.firebase:firebase-firestore:21.3.0'
}

我想念什么？

Answer 1

在pubspec.yaml文件中添加FlutterFire插件，如下所示

dependencies:
  flutter:
    sdk: flutter
  # Add the dependency for the Firebase Core Flutter SDK
  firebase_core: ^0.4.0+9
  cloud_firestore: ^0.12.9+5
  firebase_database: ^3.1.0

遵循此link以获得更多详细信息

未定义的类DatabaseReference

1 个答案: