Method to update Query in Firebase and Firestore Adapters. (#1660)

Author: PatilShreyas

buildSrc/build.gradle.kts

@@ -4,4 +4,4 @@ repositories {
 
 plugins {
     `kotlin-dsl`
-}
+}

common/src/main/java/com/firebase/ui/common/BaseObservableSnapshotArray.java

@@ -160,6 +160,14 @@ public boolean isListening(@NonNull L listener) {
         return mListeners.contains(listener);
     }
 
+    /**
+     * Clear data and notify all listeners.
+     */
+    public void clear() {
+        getSnapshots().clear();
+        notifyOnDataChanged();
+    }
+
     protected final void notifyOnChildChanged(@NonNull ChangeEventType type,
                                               @NonNull S snapshot,
                                               int newIndex,

database/src/main/java/com/firebase/ui/database/FirebaseArray.java

@@ -32,7 +32,7 @@
  */
 public class FirebaseArray<T> extends ObservableSnapshotArray<T>
         implements ChildEventListener, ValueEventListener {
-    private final Query mQuery;
+    private Query mQuery;
     private final List<DataSnapshot> mSnapshots = new ArrayList<>();
 
     /**

database/src/main/java/com/firebase/ui/database/FirebaseIndexArray.java

@@ -34,7 +34,7 @@ public class FirebaseIndexArray<T> extends ObservableSnapshotArray<T>
         implements ChangeEventListener {
     private static final String TAG = "FirebaseIndexArray";
 
-    private final DatabaseReference mDataRef;
+    private DatabaseReference mDataRef;
     private final Map<DatabaseReference, ValueEventListener> mRefs = new HashMap<>();
 
     private final FirebaseArray<String> mKeySnapshots;

database/src/main/java/com/firebase/ui/database/FirebaseRecyclerAdapter.java

@@ -28,17 +28,19 @@ public abstract class FirebaseRecyclerAdapter<T, VH extends RecyclerView.ViewHol
         extends RecyclerView.Adapter<VH> implements FirebaseAdapter<T> {
     private static final String TAG = "FirebaseRecyclerAdapter";
 
-    private final ObservableSnapshotArray<T> mSnapshots;
+    private FirebaseRecyclerOptions<T> mOptions;
+    private ObservableSnapshotArray<T> mSnapshots;
 
     /**
      * Initialize a {@link RecyclerView.Adapter} that listens to a Firebase query. See
      * {@link FirebaseRecyclerOptions} for configuration options.
      */
     public FirebaseRecyclerAdapter(@NonNull FirebaseRecyclerOptions<T> options) {
+        mOptions = options;
         mSnapshots = options.getSnapshots();
 
-        if (options.getOwner() != null) {
-            options.getOwner().getLifecycle().addObserver(this);
+        if (mOptions.getOwner() != null) {
+            mOptions.getOwner().getLifecycle().addObserver(this);
         }
     }
 
@@ -117,6 +119,30 @@ public int getItemCount() {
         return mSnapshots.isListening(this) ? mSnapshots.size() : 0;
     }
 
+    /**
+     * Re-initialize the Adapter with a new set of options. Can be used to change the query
+     * without re-constructing the entire adapter.
+     */
+    public void updateOptions(@NonNull FirebaseRecyclerOptions<T> options) {
+        // Tear down old options
+        boolean wasListening = mSnapshots.isListening(this);
+        if (mOptions.getOwner() != null) {
+            mOptions.getOwner().getLifecycle().removeObserver(this);
+        }
+        mSnapshots.clear();
+        stopListening();
+
+        // Set up new options
+        mOptions = options;
+        mSnapshots = options.getSnapshots();
+        if (options.getOwner() != null) {
+            options.getOwner().getLifecycle().addObserver(this);
+        }
+        if (wasListening) {
+            startListening();
+        }
+    }
+
     @Override
     public void onBindViewHolder(@NonNull VH holder, int position) {
         onBindViewHolder(holder, position, getItem(position));

firestore/src/main/java/com/firebase/ui/firestore/FirestoreArray.java

@@ -22,7 +22,7 @@
  */
 public class FirestoreArray<T> extends ObservableSnapshotArray<T>
         implements EventListener<QuerySnapshot> {
-    private final Query mQuery;
+    private Query mQuery;
     private final MetadataChanges mMetadataChanges;
     private ListenerRegistration mRegistration;
 

firestore/src/main/java/com/firebase/ui/firestore/FirestoreRecyclerAdapter.java

@@ -25,7 +25,8 @@ public abstract class FirestoreRecyclerAdapter<T, VH extends RecyclerView.ViewHo
 
     private static final String TAG = "FirestoreRecycler";
 
-    private final ObservableSnapshotArray<T> mSnapshots;
+    private FirestoreRecyclerOptions<T> mOptions;
+    private ObservableSnapshotArray<T> mSnapshots;
 
     /**
      * Create a new RecyclerView adapter that listens to a Firestore Query.  See {@link
@@ -83,11 +84,41 @@ public T getItem(int position) {
         return mSnapshots.get(position);
     }
 
+    /**
+     * Gets the size of snapshots in adapter.
+     *
+     * @return the total count of snapshots in adapter.
+     * @see ObservableSnapshotArray#size()
+     */
     @Override
     public int getItemCount() {
         return mSnapshots.isListening(this) ? mSnapshots.size() : 0;
     }
 
+    /**
+     * Re-initialize the Adapter with a new set of options. Can be used to change the query without
+     * re-constructing the entire adapter.
+     */
+    public void updateOptions(@NonNull FirestoreRecyclerOptions<T> options) {
+        // Tear down old options
+        boolean wasListening = mSnapshots.isListening(this);
+        if (mOptions.getOwner() != null) {
+            mOptions.getOwner().getLifecycle().removeObserver(this);
+        }
+        mSnapshots.clear();
+        stopListening();
+
+        // Set up new options
+        mOptions = options;
+        mSnapshots = options.getSnapshots();
+        if (options.getOwner() != null) {
+            options.getOwner().getLifecycle().addObserver(this);
+        }
+        if (wasListening) {
+            startListening();
+        }
+    }
+
     @Override
     public void onChildChanged(@NonNull ChangeEventType type,
                                @NonNull DocumentSnapshot snapshot,