recyclerview.setLayoutManager()

Question

What is the use of recyclerview.setLayoutManager() in this code? Please elaborate it in detail.I know about recyclerview but i am confused on what is the use of setLayoutManager() here?

public class MainActivity extends AppCompatActivity {

public static final int NEW_WORD_ACTIVITY_REQUEST_CODE = 1;

private WordViewModel mWordViewModel;

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

    Toolbar toolbar = findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    RecyclerView recyclerView = findViewById(R.id.recyclerview);
    final WordListAdapter adapter = new WordListAdapter(this);
    recyclerView.setAdapter(adapter);
    recyclerView.setLayoutManager(new LinearLayoutManager(this));

Answer 1

More than a year late but the idea behind the setLayoutManager is to set the layout of the contents, i.e. list of repeating views in the recycler view. If you scroll down to the documentation here, it will tell you that there are several strategies for lists and grids so that should give you a clue. Furthermore, it tells you that without it, RecyclerView will not function i.e. there is no out of the box default.

So if you want e.g. to set the LinearLayoutto be horizontal (by default it is vertical) then you have to specify that.

LinearLayoutManager layoutManager
    = new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false);

RecyclerView myItems = findViewById(R.id.my_recycler_view);
myItems.setLayoutManager(layoutManager);