picasso does not load image on start of appication

Question

I have used picasso on my MainActivity. On start of application it does not load image from the firebase link. However, when i go to another activity and go back, it starts loading image and show it. Actually, i am trying to get user image according to user ID (uid) in post.

My MainActivity code: P.S. Sorry for such ugly coding, I am very beginner.

String userImage = null;
String postKey = null;
String uid = null;

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mDatabase = FirebaseDatabase.getInstance().getReference().child("Posts");
    mDatabaseUsers = FirebaseDatabase.getInstance().getReference("Users");
    mUsers = FirebaseDatabase.getInstance().getReference("Users");
    mDatabaseUsers.keepSynced(true);
    mAuth = FirebaseAuth.getInstance();
    mPostList = findViewById(R.id.postList);

    mPostList.setHasFixedSize(true);
    mPostList.setLayoutManager(new LinearLayoutManager(this));
}

@Override
protected void onStart() {
    super.onStart();

    mAuth.addAuthStateListener(mAuthListener);

    final FirebaseRecyclerAdapter<Post, PostViewHolder> firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<Post, PostViewHolder>(
            Post.class,
            R.layout.post_row,
            PostViewHolder.class,
            mDatabase) {

        @Override
        protected void populateViewHolder(PostViewHolder viewHolder, Post model, int position) {

            postKey = getRef(position).getKey();

            viewHolder.setImage(getUserImage());
            viewHolder.setFrom(model.getFrom());
            viewHolder.setTo(model.getTo());
            viewHolder.setPrice(model.getPrice());
            viewHolder.setDate(model.getDate());
            viewHolder.setDate(model.getDate());
            viewHolder.setCar(model.getCar());

            viewHolder.mView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {

                    Intent particularPostIntent = new Intent(MainActivity.this, ParticularPostActivity.class);
                    particularPostIntent.putExtra("PostId", postKey);
                    startActivity(particularPostIntent);
                }
            });
        }
    };

    mPostList.setAdapter(firebaseRecyclerAdapter);
}

public static class PostViewHolder extends RecyclerView.ViewHolder {

    View mView;

    public PostViewHolder(View itemView) {
        super(itemView);

        mView = itemView;
    }

    public void setFrom(String from){

        TextView postFrom = mView.findViewById(R.id.rowFrom);
        postFrom.setText("From: " +from);
    }

    public void setTo(String to){

        TextView postTo = mView.findViewById(R.id.rowTo);
        postTo.setText("To: " + to);
    }

    public void setPrice(String price){

        TextView postPrice = mView.findViewById(R.id.rowPrice);
        postPrice.setText("Price: " + price);
    }

    public void setDate(String date){

        TextView postDate = mView.findViewById(R.id.rowDate);
        postDate.setText("Date: " + date);
    }

    public void setCar(String car){

        TextView postCar = mView.findViewById(R.id.rowCar);
        postCar.setText("Car: " + car);
    }

    public void setImage(String image){

        ImageView userImageView = mView.findViewById(R.id.rowProfileImage);

        Picasso.with(mView.getContext()).setLoggingEnabled(true);
        Picasso.with(mView.getContext()).load(image).placeholder(R.mipmap.ic_account_circle_black_48dp).into(userImageView);
    }
}

public String getUserImage(){
    mDatabase.child(postKey).addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {

            uid = (String) dataSnapshot.child("userID").getValue();
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });

    mUsers.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            userImage = (String) dataSnapshot.child(uid).child("Image").getValue();
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });

    return userImage;
}

Answer 1

To solve this, i recomand you using Glide instead of Picasso. To make it work, add the following line of code in the dependencies of your build.gradle (Module: app) file.

compile 'com.github.bumptech.glide:glide:3.7.0'

To display the image just use the following line of code:

Glide.with(getApplicationContext())
    .load(photoUrl)
    .centerCrop()
    .transform(new CircleTransform(getApplicationContext()))
    .override(45,45)
    .into(imageView);

Where photoUrl is the actual url of your photo and imageView is the ImageView where you want to display the photo.