如何根据位置从回收视图中删除 Firebase 数据库密钥

Question

I'm building an app as college project for Blood Donation where user can register using Firebase authentication Email and Password and can post request for Blood which is then added to Firebase DataBase which is shown in Recycle view inside an app I'was able to complete that part.

Now I want to add button which will be visible in the recycle view with option to delete the request if He wish in case he received call from donor or if he no longer in need. But this button should only be visible to user who has posted for request and will remain hidden for other help post inside recycle adapter.

and when he click the button it should delete the particular Data from Firebase Database also.

To summarize. 1. I need button visible only to user who has posted the help request which will delete the post if he wish to

2. On click event of that Button, will also delete the particular post from Firebase Database

I'm using Firebase authentication sing in of Email and Password.

Here is the Firebase Database Structure

Here is the Code where user wants to upload the Help request and is added to firebase Data as well

public class EnquiryActivity extends AppCompatActivity {

    //UI
    Button btnRequest;
    EditText edtName,edtBlood,edtPlace,edtMobile,edtEmail;
    //DB
    DatabaseReference mHelper;
    FirebaseAuth mAuth;
    //progress
    ProgressDialog mProgress;
    @Override
    protected void onCreate(final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_enquiry);
        //initialisation
        edtBlood=(EditText)findViewById(R.id.enq_blood);
        edtMobile=(EditText)findViewById(R.id.enq_mobile);
        edtEmail=(EditText)findViewById(R.id.enq_email);
        edtName=(EditText)findViewById(R.id.enq_name);
        edtPlace=(EditText)findViewById(R.id.enq_place);
        btnRequest=(Button)findViewById(R.id.button2);
        //firebase
        mHelper= FirebaseDatabase.getInstance().getReference();
        final String mCurrentUser=FirebaseAuth.getInstance().getCurrentUser().getUid().toString();
        mAuth=FirebaseAuth.getInstance();
        //progress
        mProgress=new ProgressDialog(this);
        mProgress.setTitle("Loading");
        mProgress.setMessage("Please wait..");

        btnRequest.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                mProgress.show();
                String blood=edtBlood.getText().toString();
                String name=edtName.getText().toString();
                String mobile=edtMobile.getText().toString();
                String email=edtMobile.getText().toString();
                String  place=edtPlace.getText().toString();
                String temp=blood.toUpperCase();
                if(!TextUtils.isEmpty(blood)||!TextUtils.isEmpty(name)||!TextUtils.isEmpty(mobile)||
                        !TextUtils.isEmpty(place)){

                        HashMap<String, String> userMap = new HashMap<>();
                        userMap.put("name", name);
                        userMap.put("blood_group","Blood Group:- " + blood);
                        userMap.put("email", email);
                        userMap.put("mobile", mobile);
                        userMap.put("place","Location:- " + place);

                        mHelper.child("Help").child(mCurrentUser).setValue(userMap).addOnCompleteListener(new OnCompleteListener<Void>() {
                            @Override
                            public void onComplete(@NonNull Task<Void> task) {
                                mProgress.dismiss();
                                Toast.makeText(getApplicationContext(), "Registered Successfully..!", Toast.LENGTH_LONG).show();
                                Intent intent = new Intent(getApplicationContext(), MainActivity.class);
                                intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
                                startActivity(intent);
                            }
                        });

            }else{
                    Toast.makeText(getApplicationContext(),"Please enter the details in all fields",Toast.LENGTH_LONG).show();
                }
            }
        });


    }
}

Here is the Code where list of help post is show including user who has posted of his/her own

 * A simple {@link Fragment} subclass.
 */
public class NeedHelpFragment extends Fragment {

    FloatingActionButton floatingActionButton;
    private View mMainView;
    private RecyclerView mHelpList;
    private DatabaseReference mUsersDatabase;
    private DatabaseReference mUsers;

    private FirebaseAuth mAuth;

    private String mCurrent_user_id;

    public NeedHelpFragment() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        mMainView = inflater.inflate(R.layout.fragment_need_help, container, false);
        floatingActionButton = (FloatingActionButton) mMainView.findViewById(R.id.float_add);
        floatingActionButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                startActivity(new Intent(getActivity(), EnquiryActivity.class));
            }
        });

        //init
        mHelpList = (RecyclerView) mMainView.findViewById(R.id.need_recyclerview);
        mAuth = FirebaseAuth.getInstance();
        mUsersDatabase = FirebaseDatabase.getInstance().getReference().child("Help");
        mUsers = FirebaseDatabase.getInstance().getReference().child("Users");
        mCurrent_user_id = mAuth.getCurrentUser().getUid();

        //
        mHelpList.setHasFixedSize(true);
        LinearLayoutManager linearVertical = new LinearLayoutManager(getContext(), LinearLayoutManager.VERTICAL, false);
        mHelpList.setLayoutManager(linearVertical);

        DividerItemDecoration mDividerItemDecoration = new DividerItemDecoration(
                mHelpList.getContext(),
                linearVertical.getOrientation()
        );
        mHelpList.addItemDecoration(mDividerItemDecoration);
        return mMainView;
    }

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

        FirebaseRecyclerAdapter<Help, HelpViewHolder> friendsRecyclerViewAdapter = new FirebaseRecyclerAdapter<Help, HelpViewHolder>(

                Help.class,
                R.layout.help_single_layout,
                HelpViewHolder.class,
                mUsersDatabase) {
            @Override
            protected void populateViewHolder(final HelpViewHolder helpViewHolder, Help help, int i) {

                helpViewHolder.setDate(help.getDate());

                final String list_user_id = getRef(i).getKey();

                mUsersDatabase.child(list_user_id).addValueEventListener(new ValueEventListener() {
                    @Override
                    public void onDataChange(DataSnapshot dataSnapshot) {
                        final String userName = dataSnapshot.child("name").getValue().toString();
                        String blood = dataSnapshot.child("blood_group").getValue().toString();
                        final String phone = dataSnapshot.child("mobile").getValue().toString();
                        final String email = dataSnapshot.child("email").getValue().toString();
                        String address = dataSnapshot.child("place").getValue().toString();


                        helpViewHolder.setName(userName);
                        helpViewHolder.setBlood(blood);
                        helpViewHolder.setAddress(address);
                        helpViewHolder.setPhone(phone);
                        helpViewHolder.setEmail(email);
                        helpViewHolder.mView.setOnClickListener(new View.OnClickListener() {
                            @Override
                            public void onClick(View view) {

                                CharSequence options[] = new CharSequence[]{"Email", "Call"};

                                final AlertDialog.Builder builder = new AlertDialog.Builder(getContext());

                                builder.setTitle("Select Options");
                                builder.setItems(options, new DialogInterface.OnClickListener() {
                                    @Override
                                    public void onClick(DialogInterface dialogInterface, int i) {

                                        //Click Event for each item.
                                        if (i == 0) {

                                        }

                                        if (i == 1) {

                                            String uri = phone;


                                            if (ActivityCompat.checkSelfPermission(getActivity(), android.Manifest.permission.CALL_PHONE) != PackageManager.PERMISSION_GRANTED) {



                                            }

                                        }

                                    }
                                });

                                builder.show();

                            }
                        });


                    }

                    @Override
                    public void onCancelled(DatabaseError databaseError) {

                    }
                });

            }
        };

        mHelpList.setAdapter(friendsRecyclerViewAdapter);


    }

    // viewholder class..

    public static class HelpViewHolder extends RecyclerView.ViewHolder {
        View mView;
        public HelpViewHolder(View itemView) {
            super(itemView);
            mView = itemView;
        }
        public void setBlood(String blood){
            TextView userStatusView = (TextView) mView.findViewById(R.id.help_blood);
            userStatusView.setText(blood.toUpperCase());
        }
        public void setName(String name){

            TextView userNameView = (TextView) mView.findViewById(R.id.help_name);
            userNameView.setText(name.toUpperCase());
        }
        public void setPhone(String phone){

            TextView userNameView = (TextView) mView.findViewById(R.id.help_mobile);
            userNameView.setText(phone);
        }


        public void setEmail(String name){

            TextView userNameView = (TextView) mView.findViewById(R.id.help_email);
            userNameView.setText(name.toUpperCase());
        }


        public void setAddress(String address) {

            TextView userNameView = (TextView) mView.findViewById(R.id.help_place);
            address.toUpperCase();
            userNameView.setText(address.toUpperCase());
        }
        public void setDate(String date){


        }
    }

}

Any help is well appreciated

Thanks in advance.

Answer 1

Add delete button in your help_single_layout . And add a new key posted in firebase database to check whether this user posted or not . On that basis , you can define visibiltiy of Delete button.