Add login to android project

Question

Guys sorry if this is too trivial, but I’m starting to study android, I have an example project that you add note and edit them, this project is already working with this mainActivity:

public class MainActivity extends AppCompatActivity {
    private NotesAdapter mAdapter;
    private List<Note> notesList = new ArrayList<>();
    private CoordinatorLayout coordinatorLayout;
    private RecyclerView recyclerView;
    private TextView noNotesView;

    private DatabaseHelper db;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        coordinatorLayout = findViewById(R.id.coordinator_layout);
        recyclerView = findViewById(R.id.recycler_view);
        noNotesView = findViewById(R.id.empty_notes_view);

        db = new DatabaseHelper(this);

        notesList.addAll(db.getAllNotes());

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                showNoteDialog(false, null, -1);
            }
        });

        mAdapter = new NotesAdapter(this, notesList);
        RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getApplicationContext());
        recyclerView.setLayoutManager(mLayoutManager);
        recyclerView.setItemAnimator(new DefaultItemAnimator());
        recyclerView.addItemDecoration(new MyDividerItemDecoration(this, LinearLayoutManager.VERTICAL, 16));
        recyclerView.setAdapter(mAdapter);

        toggleEmptyNotes();

        /**
         * On long press on RecyclerView item, open alert dialog
         * with options to choose
         * Edit and Delete
         * */
        recyclerView.addOnItemTouchListener(new RecyclerTouchListener(this,
                recyclerView, new RecyclerTouchListener.ClickListener() {
            @Override
            public void onClick(View view, final int position) {
                showActionsDialog(position);
            }

            @Override
            public void onLongClick(View view, int position) {
                showActionsDialog(position);
            }
        }));
    }

    /**
     * Inserting new note in db
     * and refreshing the list
     */
    private void createNote(String note) {
        // inserting note in db and getting
        // newly inserted note id
        long id = db.insertNote(note);

        // get the newly inserted note from db
        Note n = db.getNote(id);

        if (n != null) {
            // adding new note to array list at 0 position
            notesList.add(0, n);

            // refreshing the list
            mAdapter.notifyDataSetChanged();

            toggleEmptyNotes();
        }
    }

    /**
     * Updating note in db and updating
     * item in the list by its position
     */
    private void updateNote(String note, int position) {
        Note n = notesList.get(position);
        // updating note text
        n.setNote(note);

        // updating note in db
        db.updateNote(n);

        // refreshing the list
        notesList.set(position, n);
        mAdapter.notifyItemChanged(position);

        toggleEmptyNotes();
    }

    /**
     * Deleting note from SQLite and removing the
     * item from the list by its position
     */
    private void deleteNote(int position) {
        // deleting the note from db
        db.deleteNote(notesList.get(position));

        // removing the note from the list
        notesList.remove(position);
        mAdapter.notifyItemRemoved(position);

        toggleEmptyNotes();
    }

    /**
     * Opens dialog with Edit - Delete options
     * Edit - 0
     * Delete - 0
     */
    private void showActionsDialog(final int position) {
        CharSequence colors[] = new CharSequence[]{"Edit", "Delete"};

        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("Choose option");
        builder.setItems(colors, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                if (which == 0) {
                    showNoteDialog(true, notesList.get(position), position);
                } else {
                    deleteNote(position);
                }
            }
        });
        builder.show();
    }


    /**
     * Shows alert dialog with EditText options to enter / edit
     * a note.
     * when shouldUpdate=true, it automatically displays old note and changes the
     * button text to UPDATE
     */
    private void showNoteDialog(final boolean shouldUpdate, final Note note, final int position) {
        LayoutInflater layoutInflaterAndroid = LayoutInflater.from(getApplicationContext());
        View view = layoutInflaterAndroid.inflate(R.layout.note_dialog, null);

        AlertDialog.Builder alertDialogBuilderUserInput = new AlertDialog.Builder(MainActivity.this);
        alertDialogBuilderUserInput.setView(view);

        final EditText inputNote = view.findViewById(R.id.note);
        TextView dialogTitle = view.findViewById(R.id.dialog_title);
        dialogTitle.setText(!shouldUpdate ? getString(R.string.lbl_new_note_title) : getString(R.string.lbl_edit_note_title));

        if (shouldUpdate && note != null) {
            inputNote.setText(note.getNote());
        }
        alertDialogBuilderUserInput
                .setCancelable(false)
                .setPositiveButton(shouldUpdate ? "update" : "save", new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialogBox, int id) {

                    }
                })
                .setNegativeButton("cancel",
                        new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialogBox, int id) {
                                dialogBox.cancel();
                            }
                        });

        final AlertDialog alertDialog = alertDialogBuilderUserInput.create();
        alertDialog.show();

        alertDialog.getButton(AlertDialog.BUTTON_POSITIVE).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // Show toast message when no text is entered
                if (TextUtils.isEmpty(inputNote.getText().toString())) {
                    Toast.makeText(MainActivity.this, "Enter note!", Toast.LENGTH_SHORT).show();
                    return;
                } else {
                    alertDialog.dismiss();
                }

                // check if user updating note
                if (shouldUpdate && note != null) {
                    // update note by it's id
                    updateNote(inputNote.getText().toString(), position);
                } else {
                    // create new note
                    createNote(inputNote.getText().toString());
                }
            }
        });
    }

    /**
     * Toggling list and empty notes view
     */
    private void toggleEmptyNotes() {
        // you can check notesList.size() > 0

        if (db.getNotesCount() > 0) {
            noNotesView.setVisibility(View.GONE);
        } else {
            noNotesView.setVisibility(View.VISIBLE);
        }
    }
}

So there in the view tablet, I went with the right button and added a new Loginactivity, android created a java class and an xml, with its standards.

What I wanted, that the first time I started my project, it asked for the information on the login screen, (for now ta with password and login, then I want to ask for the name and an image), and when the person clicked on the button went to the screen to insert the notes, after the first time the person entered the login information, it was no longer requested, but there was the option to edit.

Currently my main xml is like this:

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/coordinator_layout"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="info.androidhive.sqlite.view.MainActivity">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/AppTheme.PopupOverlay" />

    </android.support.design.widget.AppBarLayout>

    <include layout="@layout/content_main" />

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="@dimen/fab_margin"
        app:srcCompat="@drawable/ic_add_white_24dp" />

</android.support.design.widget.CoordinatorLayout>

Can anyone help me or point out what changes I should make?

I am mostly doubtful, because to insert the notes I had to create a class for sqlite, both to make the creation of the base, as one for the template of the notes, in case of login I will have to do too? Or there is already a treat of this in android standard?

I imagine that the test already exists the login do on the main onCreate, but I have no idea how to make a conditional to appear login screen, or the screen of notes. And nor as in the standard Activity login, how do I so enter the information go to the other screen.