import com.google.firebase.firestore.FirebaseFirestoreSettings; //导入依赖的package包/类
@Override
public void onCreate() {
    super.onCreate();
    LocalBroadcastManager.getInstance(this);
    FirebaseApp.initializeApp(this);
    FirebaseFirestoreSettings settings = new FirebaseFirestoreSettings.Builder()
            .setPersistenceEnabled(true)
            .build();
    FirebaseFirestore.getInstance().setFirestoreSettings(settings);
}
 

import com.google.firebase.firestore.FirebaseFirestoreSettings; //导入依赖的package包/类
private void setup() {
    // [START get_firestore_instance]
    FirebaseFirestore db = FirebaseFirestore.getInstance();
    // [END get_firestore_instance]

    // [START set_firestore_settings]
    FirebaseFirestoreSettings settings = new FirebaseFirestoreSettings.Builder()
            .setPersistenceEnabled(true)
            .build();
    db.setFirestoreSettings(settings);
    // [END set_firestore_settings]
}
 

import com.google.firebase.firestore.FirebaseFirestoreSettings; //导入依赖的package包/类
@Before
public void setUp() throws Exception {
    FirebaseApp app = getAppInstance(InstrumentationRegistry.getContext());

    // Configure Firestore and disable persistence
    FirebaseFirestore.getInstance(app)
            .setFirestoreSettings(new FirebaseFirestoreSettings.Builder()
                    .setPersistenceEnabled(false)
                    .build());

    // Get a fresh 'test' subcollection for each test
    mCollectionRef = FirebaseFirestore.getInstance(app).collection("firestorearray")
            .document().collection("test");

    Log.d(TAG, "Test Collection: " + getConsoleLink(mCollectionRef));

    // Query is the whole collection ordered by field
    mArray = new FirestoreArray<>(
            mCollectionRef.orderBy("field", Query.Direction.ASCENDING),
            new ClassSnapshotParser<>(IntegerDocument.class));

    // Add a listener to the array so that it's active
    mListener = mArray.addChangeEventListener(new LoggingListener());

    // Add some initial data
    runAndVerify(new Callable<Task<?>>() {
        @Override
        public Task<?> call() {
            List<Task> tasks = new ArrayList<>();
            for (int i = 0; i < INITIAL_SIZE; i++) {
                tasks.add(mCollectionRef.document().set(new IntegerDocument(i)));
            }

            return Tasks.whenAll(tasks.toArray(new Task[tasks.size()]));
        }
    }, new Callable<Boolean>() {
        @Override
        public Boolean call() {
            return mArray.size() == INITIAL_SIZE;
        }
    });
}