Saved Games Snapshot Initialization (null Object Reference)

I am trying to use the new Saved Games (Snapshot) API But I keep getting this error: java.lang.NullPointerException: Attempt to invoke interface method 'boolean com.google.android.

Solution 1:

The Snapshot API is very specific in how you must do things. The following is the high-level procedure for Snapshot save:

• Open the snapshot
• Resolve conflicts
• Save

The following code is from the Google Play Games Snapshot sample which shows you how to use Snapshots cross-platform across Android and iOS.

First, you must open the snapshot and resolve conflicts on open.

/**
 * Prepares saving Snapshot to the user's synchronized storage, conditionally resolves errors,
 * and stores the Snapshot.
 */voidsaveSnapshot() {
    AsyncTask<Void, Void, Snapshots.OpenSnapshotResult> task =
            newAsyncTask<Void, Void, Snapshots.OpenSnapshotResult>() {
                @OverrideprotectedSnapshots.OpenSnapshotResultdoInBackground(Void... params) {
                    Snapshots.OpenSnapshotResult result = Games.Snapshots.open(getApiClient(),
                            currentSaveName, true).await();
                    return result;
                }

                @OverrideprotectedvoidonPostExecute(Snapshots.OpenSnapshotResult result) {
                    Snapshot toWrite = processSnapshotOpenResult(result, 0);

                    Log.i(TAG, writeSnapshot(toWrite));
                }
            };

    task.execute();
}

Next, you must handle conflict resolution:

/**
 * Conflict resolution for when Snapshots are opened.
 * @param result The open snapshot result to resolve on open.
 * @return The opened Snapshot on success; otherwise, returns null.
 */
Snapshot processSnapshotOpenResult(Snapshots.OpenSnapshotResult result, int retryCount){
    SnapshotmResolvedSnapshot=null;
    retryCount++;
    intstatus= result.getStatus().getStatusCode();

    Log.i(TAG, "Save Result status: " + status);

    if (status == GamesStatusCodes.STATUS_OK) {
        return result.getSnapshot();
    } elseif (status == GamesStatusCodes.STATUS_SNAPSHOT_CONTENTS_UNAVAILABLE) {
        return result.getSnapshot();
    } elseif (status == GamesStatusCodes.STATUS_SNAPSHOT_CONFLICT){
        Snapshotsnapshot= result.getSnapshot();
        SnapshotconflictSnapshot= result.getConflictingSnapshot();

        // Resolve between conflicts by selecting the newest of the conflicting snapshots.
        mResolvedSnapshot = snapshot;

        if (snapshot.getMetadata().getLastModifiedTimestamp() <
                conflictSnapshot.getMetadata().getLastModifiedTimestamp()){
            mResolvedSnapshot = conflictSnapshot;
        }

        Snapshots.OpenSnapshotResultresolveResult= Games.Snapshots.resolveConflict(
                getApiClient(), result.getConflictId(), mResolvedSnapshot)
                .await();

        if (retryCount < MAX_SNAPSHOT_RESOLVE_RETRIES){
            return processSnapshotOpenResult(resolveResult, retryCount);
        }else{
            Stringmessage="Could not resolve snapshot conflicts";
            Log.e(TAG, message);
            Toast.makeText(getBaseContext(), message, Toast.LENGTH_LONG);
        }

    }
    // Fail, return null.returnnull;
}

The following code is how this is done in the Google Play Games Snapshots sample app:

/**
 * Generates metadata, takes a screenshot, and performs the write operation for saving a
 * snapshot.
 */privateStringwriteSnapshot(Snapshot snapshot){
    // Set the data payload for the snapshot.
    snapshot.writeBytes(mSaveGame.toBytes());

    // Save the snapshot.SnapshotMetadataChange metadataChange = newSnapshotMetadataChange.Builder()
            .setCoverImage(getScreenShot())
            .setDescription("Modified data at: " + Calendar.getInstance().getTime())
            .build();
    Games.Snapshots.commitAndClose(getApiClient(), snapshot, metadataChange);
    return snapshot.toString();
}

Solution 2:

I think, instead of creating Snapshot object explicitly. It should get generated in onActivityResult. So you need to handle it in onActivityResult. Then your writeBytes() will perform further operations.

Check documentation, In that loadFromSnapshot() contains

Snapshotsnapshot= result.getSnapshot();

So I think, you are getting null/false response on your onActivityResult. If not then follow same steps given in loadFromSnapshot() documentation.