Android RecyclerView + ActiveAndroid [英] Android RecyclerView + ActiveAndroid

问题描述

使用ActiveAndroid ORM填充RecyclerView并跟踪数据更改的首选方法是什么？

What is the preffered way of populating a RecyclerView and keeping track of data changes using ActiveAndroid ORM?

我已经最近对此主题提出了疑问。但是它太冗长了，人们是如此懒惰，以至于几乎没人读到最后。

I've asked a question on this topic recently. But it got too verbose, and people are so lazy, that someone would scarcely read it till the end.

它的本质：有人有吗一个通过ActiveAndroid从数据库填充的RecyclerView的工作示例？

The very essence of it: Does somebody have a working example of RecyclerView populated from a database through ActiveAndroid?

推荐答案

每当我向其中添加数据时，我都会使用eventbus通知我的recyclerview适配器我的数据库。

I use eventbus to notify my recyclerview's adapter whenever i add data to my database.

MainActivity.java

MainActivity.java

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private final String TAG = "MainActivity";
    private EditText etName, etAge;
    private Button btnAdd;
    private EventBus bus = EventBus.getDefault();

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

        //declare all views
        etName = (EditText) findViewById(R.id.et_name);
        etAge = (EditText) findViewById(R.id.et_age);
        btnAdd = (Button) findViewById(R.id.btn_add);

        //add onClickListener to button
        btnAdd.setOnClickListener(this);

        android.support.v4.app.FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
        transaction.replace(R.id.frame_layout, ListFragment.newInstance());
        transaction.commit();
    }

    @Override
    public void onClick(View v) {
        int id = v.getId();

        switch (id) {
            case R.id.btn_add:
                PersonModel personModel = new PersonModel();

                if (isEmpty(etName) || isEmpty(etAge)) {
                    Toast.makeText(this, "Please fill in all details", Toast.LENGTH_LONG).show();
                } else {
                    personModel.name = etName.getText().toString();
                    personModel.age = etAge.getText().toString();

                    //Save data to database
                    personModel.save();

                    //Broadcast the event to notify fragment
                    bus.post("NOTIFY");
                }
                break;
            default:
                Log.e(TAG, "Invalid view ID");
                break;
        }
    }

    //Check edit text whether is empty or not
    private boolean isEmpty(EditText etText) {
        return etText.getText().toString().trim().length() == 0;
    }
}

PersonModel.java

PersonModel.java

@Table(name = "PersonModel")
public class PersonModel extends Model {
    @Column(name = "NAME")
    public String name;

    @Column(name = "AGE")
    public String age;
}

PersonAdapter.java

PersonAdapter.java

public class PersonAdapter extends RecyclerView.Adapter<PersonAdapter.MyViewHolder> {
    private Context mContext;
    private List<PersonModel> models;

    public PersonAdapter(Context context, List<PersonModel> models) {
        this.mContext = context;
        this.models = models;
    }

    public class MyViewHolder extends RecyclerView.ViewHolder {
        public TextView name, age;

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

            name = (TextView) itemView.findViewById(R.id.name);
            age = (TextView) itemView.findViewById(R.id.age);
        }
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View itemView = LayoutInflater.from(mContext).inflate(R.layout.person_cell, parent, false);

        return new MyViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {
        PersonModel personModel = models.get(position);

        holder.name.setText(personModel.name);
        holder.age.setText(personModel.age);
    }

    @Override
    public int getItemCount() {
        return models.size();
    }
}

ListFragment.java

ListFragment.java

public class ListFragment extends Fragment {
    private final String TAG = "ListFragment";
    private EventBus bus = EventBus.getDefault();
    private List<PersonModel> models = new ArrayList<PersonModel>();
    private Context mContext;
    private RecyclerView recyclerView;
    private PersonAdapter personAdapter;

    public static ListFragment newInstance() {
        // Required empty public constructor
        ListFragment listFragment = new ListFragment();

        return listFragment;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View rootView = inflater.inflate(R.layout.fragment_list, container, false);

        bus.register(this);

        recyclerView = (RecyclerView) rootView.findViewById(R.id.list_rv);

        //Load and add all data from database to array list
        models = getAll();

        personAdapter = new PersonAdapter(mContext, models);
        RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(mContext);
        recyclerView.setLayoutManager(mLayoutManager);
        recyclerView.setItemAnimator(new DefaultItemAnimator());
        recyclerView.setAdapter(personAdapter);
        personAdapter.notifyDataSetChanged();

        return rootView;
    }

    //Load all data from database
    private List<PersonModel> getAll() {
        return new Select()
                .all()
                .from(PersonModel.class)
                .orderBy("NAME ASC")
                .execute();
    }

    //Load the last data added to database
    private List<PersonModel> getLast() {
        return new Select()
                .all()
                .from(PersonModel.class)
                .orderBy("NAME DESC")
                .limit(1)
                .execute();
    }

    //Subscribe to event bus
    //Receive notification/event from MainActivity when added a data to database
    @Subscribe(threadMode = ThreadMode.MAIN)
    public void onEventMainThread(String STATUS) {
        switch (STATUS) {
            case "NOTIFY":
                //Add last added item to current array list
                models.add(getLast().get(0));

                //refresh recyclerView's adapter
                personAdapter.notifyDataSetChanged();
                break;
            default:
                Log.e(TAG, "Invalid STATUS");
        }
    }

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);

        this.mContext = context;
    }
}

这篇关于Android RecyclerView + ActiveAndroid的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！