CategoryActivity.java

package com.example.todos;

import android.app.LoaderManager;
import android.content.ContentValues;
import android.content.CursorLoader;
import android.content.DialogInterface;
import android.content.Loader;
import android.database.Cursor;
import android.databinding.DataBindingUtil;
import android.databinding.ObservableArrayList;
import android.net.Uri;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;
import com.example.todos.data.TodosContract;
import com.example.todos.data.TodosQueryHandler;
import com.example.todos.databinding.ActivityCategoryBinding;
import com.example.todos.model.Category;
import com.example.todos.model.CategoryList;

public class CategoryActivity extends AppCompatActivity
        implements LoaderManager.LoaderCallbacks<Cursor>{
    protected Category category;
    protected CategoryList categories;
    private static final int URL_LOADER = 0;
    ObservableArrayList<Category> list;
    Cursor cursor;
    CategoryListAdapter adapter;
    ActivityCategoryBinding binding;
    TodosQueryHandler handler;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        LayoutInflater inflater = getLayoutInflater();
        binding = DataBindingUtil.setContentView(this, R.layout.activity_category);
        getLoaderManager().initLoader(URL_LOADER, null, this);
        handler =  new TodosQueryHandler(getContentResolver());
    }
    
    @Override
    public void onResume(){
        getLoaderManager().restartLoader(URL_LOADER, null, this);
        super.onResume();
    }

    @Override
    public Loader<Cursor> onCreateLoader(int id, Bundle args) {
        String[] projection = {TodosContract.CategoriesEntry.TABLE_NAME
                + "." + TodosContract.CategoriesEntry._ID,
                TodosContract.CategoriesEntry.COLUMN_DESCRIPTION};
        return new CursorLoader(
                this,
                TodosContract.CategoriesEntry.CONTENT_URI,
                projection,
                null, null, null);
    }

    @Override
    public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
        final ListView lv=(ListView) findViewById(R.id.lvCategories);
        list = new ObservableArrayList<>();
        int i=0;
        //fills the observablelist of categories
        // Move cursor before first so we can still iterate after config change
        data.moveToPosition(-1);
        while (data.moveToNext())
        {
            list.add(i, new Category(
                    data.getInt(0),
                    data.getString(1)
            ));
            i++;
        }
        adapter = new CategoryListAdapter(list);
        lv.setAdapter(adapter);
        //set bindings
        //classes
        category = new Category();
        categories = new CategoryList(list);
        binding.setCategories(categories);
        binding.setCategory(category);
    }

    @Override
    public void onLoaderReset(Loader<Cursor> loader) {
        adapter.list = null;
    }
}