How to use

getInBackground

method

in

com.avos.avoscloud.AVQuery

/**
 * Constructs a AVObject whose id is already known by fetching data from the server in a
 * background thread. This does not use caching. This is preferable to using the
 * AVObject(className, objectId) constructor, unless your code is already running in a background
 * thread.
 *
 * @param objectId Object id of the AVObject to fetch
 * @param callback callback.done(object, e) will be called when the fetch completes.
 */
public void getInBackground(String objectId, GetCallback<T> callback) {
 final GetCallback<T> internalCallback = callback;
 this.getInBackground(objectId, false, new GetCallback<T>() {
  @Override
  public void done(T object, AVException e) {
   if (internalCallback != null) {
    internalCallback.internalDone(object, e);
   }
  }
 });
}

/**
 * Constructs a AVObject whose id is already known by fetching data from the server in a
 * background thread. This does not use caching. This is preferable to using the
 * AVObject(className, objectId) constructor, unless your code is already running in a background
 * thread.
 *
 * @param objectId Object id of the AVObject to fetch
 * @param callback callback.done(object, e) will be called when the fetch completes.
 */
public void getInBackground(String objectId, GetCallback<T> callback) {
 final GetCallback<T> internalCallback = callback;
 this.getInBackground(objectId, false, new GetCallback<T>() {
  @Override
  public void done(T object, AVException e) {
   if (internalCallback != null) {
    internalCallback.internalDone(object, e);
   }
  }
 });
}

/**
 * Retrieve a AVFile object by object id from AVOSCloud in background.If the file is not found,it
 * will call the callback with java.io.FileNotFoundException.
 *
 * @param objectId The file object id.
 * @param cb The GetFileCallback instance.
 * @since 2.0.2
 */
public static void withObjectIdInBackground(final String objectId,
  final GetFileCallback<AVFile> cb) {
 AVQuery<AVObject> query = new AVQuery<AVObject>("_File");
 query.getInBackground(objectId, new GetCallback<AVObject>() {
  @Override
  public void done(AVObject object, AVException e) {
   if (e != null) {
    cb.internalDone(null, e);
    return;
   }
   if (object != null && !AVUtils.isBlankString(object.getObjectId())) {
    AVFile file = createFileFromAVObject(object);
    if (cb != null) {
     cb.internalDone(file, null);
    }
   } else {
    cb.internalDone(null, new AVException(AVException.OBJECT_NOT_FOUND,
      "Could not find file object by id:" + objectId));
   }
  }
 });
}

                     final GetFileCallback<AVFile> cb) {
AVQuery<AVObject> query = new AVQuery<AVObject>("_File");
query.getInBackground(objectId, new GetCallback<AVObject>() {

/**
 * Constructs a AVObject whose id is already known by fetching data from the server. This mutates
 * the AVQuery.
 *
 * @param theObjectId Object id of the AVObject to fetch.
 */
@SuppressWarnings("unchecked")
public T get(String theObjectId) throws AVException {
 final Object[] result = {null};
 this.getInBackground(theObjectId, true, new GetCallback<T>() {
  @Override
  public void done(T object, AVException e) {
   if (e == null) {
    result[0] = object;
   } else {
    AVExceptionHolder.add(e);
   }
  }
  @Override
  protected boolean mustRunOnUIThread() {
   return false;
  }
 });
 if (AVExceptionHolder.exists()) {
  throw AVExceptionHolder.remove();
 }
 return (T) result[0];
}

/**
 * Constructs a AVObject whose id is already known by fetching data from the server. This mutates
 * the AVQuery.
 *
 * @param theObjectId Object id of the AVObject to fetch.
 */
@SuppressWarnings("unchecked")
public T get(String theObjectId) throws AVException {
 final Object[] result = {null};
 this.getInBackground(theObjectId, true, new GetCallback<T>() {
  @Override
  public void done(T object, AVException e) {
   if (e == null) {
    result[0] = object;
   } else {
    AVExceptionHolder.add(e);
   }
  }
  @Override
  protected boolean mustRunOnUIThread() {
   return false;
  }
 });
 if (AVExceptionHolder.exists()) {
  throw AVExceptionHolder.remove();
 }
 return (T) result[0];
}