How to add timestamp for CardView - date

Question

I am using FirebaseRecyclerAdapter my issue or problem is that I need to show timestamp for my posts card so I have searched for 3 months and I couldn't solve this problem so please brother I have done my best and it's time for getting help from others be in mind that I don't have any idea about timestamp ...
here's an example for how I want to show : 3 hours ago, 1 day, just now.
If some one solve me this problem by adding the solve for my JAVA fragment I will be proud for him.
Here's my fragment
public class Challenges extends Fragment{
private RecyclerView mPostList;
private DatabaseReference mDatabase,mDatabaseFriends,mDatabaseLike;
private SwipeRefreshLayout mRefreshLayout;
private boolean mProcessLike = false;
private String AA;
private FirebaseAuth mAuth;
private FirebaseAuth.AuthStateListener mListener;
private Query mQuery;
private FirebaseUser mCurrentUser;
public Challenges() {}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
MultiDex.install(getActivity());}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v= inflater.inflate(R.layout.challenges, container, false);
mListener = new FirebaseAuth.AuthStateListener() {
#Override
public void onAuthStateChanged(#NonNull FirebaseAuth firebaseAuth) {
final FirebaseUser User = firebaseAuth.getCurrentUser();
if (User == null) {
Intent A = new Intent(getActivity(), Login.class);
startActivity(A);}}};
mPostList=(RecyclerView)v.findViewById(R.id.PostList);
mPostList.setHasFixedSize(true);
mPostList.setItemAnimator(new DefaultItemAnimator());
mPostList.setLayoutManager(new LinearLayoutManager(getActivity()));
//Firebase
mDatabase= FirebaseDatabase.getInstance().getReference().child("Posts");
mDatabaseFriends= FirebaseDatabase.getInstance().getReference().child("Friends");
mDatabaseLike = FirebaseDatabase.getInstance().getReference().child("Likes");
mDatabase.keepSynced(true);
mDatabaseLike.keepSynced(true);
mAuth = FirebaseAuth.getInstance();
mCurrentUser = mAuth.getCurrentUser();
mRefreshLayout=(SwipeRefreshLayout)v.findViewById(R.id.RefreshLayout);
//mQuery = mDatabase.orderByChild("UID").equalTo(String.valueOf(mDatabaseFriends.child(mCurrentUser.getUid()).child("Accepted")));
mRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
#Override
public void onRefresh() {
onStart();}});
return v;}
#Override
public void onStart() {
super.onStart();
mAuth.addAuthStateListener(mListener);
mRefreshLayout.setRefreshing(true);
final FirebaseRecyclerAdapter<Getting_Posts, PostViewHolder> firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<Getting_Posts, PostViewHolder>(
Getting_Posts.class, R.layout.post_card_design, PostViewHolder.class, mDatabase) {
#SuppressLint("SetTextI18n")
#Override
protected void populateViewHolder(final PostViewHolder viewHolder, final Getting_Posts model, int position) {
final String Post_Key = getRef(position).getKey();
viewHolder.mView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent A = new Intent(getActivity(), com.pcsoftgroup.test.activities.Single_view.class);
A.putExtra("Key", Post_Key);
startActivity(A);}
});
viewHolder.setUsername(model.getUsername());
viewHolder.setProfile(getActivity().getApplicationContext(), model.getProfile());
viewHolder.setDescribe(model.getDescribe());
viewHolder.setWallpaper(getActivity().getApplicationContext(), model.getWallpaper());
viewHolder.setLike(Post_Key);
viewHolder.setLikeNum(Post_Key);
viewHolder.setCommentNum(Post_Key);
viewHolder.mPostTime.setText(model.getTime());
viewHolder.mLike.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
mProcessLike = true;
mDatabaseLike.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (mProcessLike) {
if (dataSnapshot.child(Post_Key).hasChild(mCurrentUser.getUid())) {
mDatabaseLike.child(Post_Key).child(mCurrentUser.getUid()).removeValue();
mProcessLike = false;
} else {
mDatabaseLike.child(Post_Key).child(mCurrentUser.getUid()).setValue("LIKED");
mProcessLike = false;
}
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
});
viewHolder.mShare.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent sendIntent = new Intent();
sendIntent.setAction(Intent.ACTION_SEND);
//sendIntent.putExtra(Intent.EXTRA_TEXT,viewHolder.mComment.getText().toString());
sendIntent.setType("text/plain");
Intent.createChooser(sendIntent, "Share via");
startActivity(sendIntent);
}
});
mRefreshLayout.setRefreshing(false);
mRefreshLayout.setEnabled(true);
}
};
mPostList.setAdapter(firebaseRecyclerAdapter);}
public static class PostViewHolder extends RecyclerView.ViewHolder{
//Main
View mView;
ImageButton mLike;
ImageButton mCommentBtn;
ImageButton mShare;
//Firebase
FirebaseAuth mAuth;
FirebaseUser mCurrentUser;
DatabaseReference mDatabaseLike;
DatabaseReference mDatabaseComment;
public PostViewHolder(View itemView) {
super(itemView);
//Main
mView=itemView;
mLike=(ImageButton) mView.findViewById(R.id.PostLike);
mCommentBtn = (ImageButton) mView.findViewById(R.id.PostCommentBtn);
mShare = (ImageButton) mView.findViewById(R.id.PostShare);
//Firebase
mAuth =FirebaseAuth.getInstance();
mCurrentUser=mAuth.getCurrentUser();
mDatabaseComment = FirebaseDatabase.getInstance().getReference().child("Comments");
mDatabaseLike= FirebaseDatabase.getInstance().getReference().child("Likes");
mDatabaseLike.keepSynced(true);
mDatabaseComment.keepSynced(true);
}
//Like
void setLike(final String Post_Key){
mDatabaseLike.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.child(Post_Key).hasChild(mCurrentUser.getUid())){
mLike.setImageResource(R.drawable.like_icon);
}else {mLike.setImageResource(R.drawable.unlike_icon);}}
#Override
public void onCancelled(DatabaseError databaseError) {}});}
void setLikeNum(final String Post_Key){
mDatabaseLike.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
String A = String.valueOf(dataSnapshot.child(Post_Key).getChildrenCount());
TextView PostLikeNum = (TextView) mView.findViewById(R.id.PostLikeNum);
PostLikeNum.setText(A);}
#Override
public void onCancelled(DatabaseError databaseError) {}});}
void setCommentNum(final String Post_Key){
mDatabaseComment.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
String C = String.valueOf(dataSnapshot.child(Post_Key).getChildrenCount());
TextView PostCommentNum = (TextView) mView.findViewById(R.id.PostCommentNum);
PostCommentNum.setText(C);}
#Override
public void onCancelled(DatabaseError databaseError) {}});}
//Username
public void setUsername(String Username){
TextView PostUsername = (TextView) mView.findViewById(R.id.PostUsername);
PostUsername.setText(Username);}
//Profile
void setProfile(Context ctx2, String Profile){
ImageView PostProfile = (ImageView) mView.findViewById(R.id.PostUserImage);
if (Profile == null){PostProfile.setVisibility(View.VISIBLE);}
else {PostProfile.setVisibility(View.VISIBLE);
Picasso.with(ctx2).load(Profile).resize(120,120).into(PostProfile);}}
//Describe
void setDescribe(String Describe){
TextView PostDescribe = (TextView) mView.findViewById(R.id.PostDesc);
PostDescribe.setText(Describe);}
//Image Load
void setWallpaper(Context ctx, String Image){
ImageView PostWallpaper = (ImageView) mView.findViewById(R.id.PostWallpaper);
if (Image == null){PostWallpaper.setVisibility(View.VISIBLE);}
else {
PostWallpaper.setVisibility(View.VISIBLE);
Picasso.with(ctx).load(Image).resize(1200,600).into(PostWallpaper);}}
}}
And here's my getter and setter java:
public class Getting_Posts {
private String Username;
private String Profile;
private String Describe;
private String Wallpaper;
public Getting_Posts() {
}
public Getting_Posts(String Username, String Profile, String Describe, String Wallpaper) {
this.Username = Username;
this.Profile = Profile;
this.Describe = Describe;
this.Wallpaper = Wallpaper;
}
public String getDescribe() {
return Describe;
}
public void setDescribe(String describe) {
Describe = describe;
}
public String getWallpaper() {
return Wallpaper;
}
public void setWallpaper(String wallpaper) {
Wallpaper = wallpaper;
}
public String getUsername() {
return Username;
}
public void setUsername(String username) {
Username = username;
}
public String getProfile() {
return Profile;
}
public void setProfile(String profile) {
Profile = profile;
}
}