I'm trying to migrate a Parse project to Backendless. Therefore, I'm following a Tutorial to learn Backendless. The Tutorial is by Samantha Squires, and it's on Youtube. What I'm building here is the ability to add 2 people as a friend. I'm logged in as a testuser and I want to add a friend to my friend list. Here's the method to add 2 friends as a friend in Backendless. I get the following error message:
E/AndroidRuntime: FATAL EXCEPTION: IntentService[AddFriendService]
java.lang.NoClassDefFoundError: java.util.Objects
at com.backendless.Persistence.find(Persistence.java:638)
at com.backendless.DataStoreFactory$1.find(DataStoreFactory.java:188)
at com.example.muhammadahsan.a27sam01.AddFriendService.addFriends(AddFriendService.java:121)
at com.example.muhammadahsan.a27sam01.AddFriendService.onHandleIntent(AddFriendService.java:90)
at android.app.IntentService$ServiceHandler.handleMessage(IntentService.java:65)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.os.HandlerThread.run(HandlerThread.java:61)
My method to add 2 people as a friend is:
private void addFriends (String firstUserName, String secondUserName){
Log.i("addFriendsMethod: ", "addFriendsMethod is Running");
DataQueryBuilder query = DataQueryBuilder.create();
query.setWhereClause(String.format("name = '%s' or name = '%s'", firstUserName, secondUserName));
Backendless.Persistence.of(BackendlessUser.class).find(query, new AsyncCallback<List<BackendlessUser>>() {
@Override
public void handleResponse(List<BackendlessUser> response) {
Log.i("Query Response:" , response.toString());
List<BackendlessUser> users = response;
if (users.size() !=2){
broadcastAddFriendFailure();
//That means we have more that one users or one of users wasn't found
} else {
BackendlessUser user1 = users.get(0);//First user
final BackendlessUser user2 = users.get(1);//Second user
//Update first user, adding second user as a friend.
updateFriendsList(user1,user2);
Backendless.UserService.update(user1, new AsyncCallback<BackendlessUser>() {
@Override
public void handleResponse(BackendlessUser user) {
//Now Update second user adding first user as a friend
updateFriendsList(user2, user);//user is the updated version of user1
Backendless.UserService.update(user2, new AsyncCallback<BackendlessUser>() {
@Override
public void handleResponse(BackendlessUser response) {
broadcastAddFriendSuccess();
}
@Override
public void handleFault(BackendlessFault fault) {
broadcastAddFriendFailure();
}
});
}
@Override
public void handleFault(BackendlessFault fault) {
broadcastAddFriendFailure();
}
});
}
}
@Override
public void handleFault(BackendlessFault fault) {
}
});
}
I know there's something wrong with the
Backendless.Persistence.of(BackendlessUser.class).find(query, new AsyncCallback<List<BackendlessUser>>()
Because I tried to test the output of whereclause in logs. Any help will be appreciated.
It seems that in order to use Backendless SDK you have to specify Android SDK 19+ as minimal. The reason is that the Objects class' static methods (which apparently Backendless SDK uses) are only available from this version.