TechnologyFragment.java

package com.example.raphaelli.bestnews;

/**
 * Created by Raphaelli on 12/04/2018.
 */

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.net.Uri;
import android.support.annotation.Nullable;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.LoaderManager;
import android.support.v4.content.Loader;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListView;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

public class TechnologyFragment extends Fragment implements LoaderManager.LoaderCallbacks<List<Report>> {
    private static final String THE_GUARDIAN_BASE_URL = "https://content.guardianapis.com/search";

    private static final String API_KEY = "7f497332-f1f5-4b2b-b30b-3b343464fc2b";

    private static final int REPORT_LOADER_ID = 1;

    private static final String LOG_TAG = TechnologyFragment.class.getName();

    /** Adapter da lista de reports */
    private ReportAdapter mAdapter;

    /** TextView that is displayed when the list is empty */
    private TextView mEmptyStateTextView;

    private View mLoadingIndicator;

    /** List of reports */
    private ListView mReportListView;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_technology, container, false);

        // Find a reference to the {@link ListView} in the layout
        mReportListView = (ListView) rootView.findViewById(R.id.list);
        mAdapter = new ReportAdapter(getActivity(), new ArrayList<Report>());
        mReportListView.setAdapter(mAdapter);

        // Find the reference to the empty text view in a layout and set empty view
        mEmptyStateTextView = (TextView) rootView.findViewById(R.id.empty_view);
        mLoadingIndicator = (View) rootView.findViewById(R.id.progress_bar);

        return rootView;
    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        if (isConnected()) {
            getLoaderManager().initLoader(REPORT_LOADER_ID, null, this);
        } else {
            mEmptyStateTextView.setVisibility(View.VISIBLE);
            mReportListView.setVisibility(View.GONE);
            mEmptyStateTextView.setText("Não foi possível conectar");
        }
    }

    // Helper method to check network connection
    private boolean isConnected() {
        ConnectivityManager connectivityManager = (ConnectivityManager) getActivity().getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
        return (networkInfo != null && networkInfo.isConnected());
    }


    @Override
    public Loader<List<Report>> onCreateLoader(int id, Bundle args) {

        // Parse breaks apart the URI string that is passed into its parameter
        Uri baseUri = Uri.parse(THE_GUARDIAN_BASE_URL);

        // buildUpon prepares the baseUri that we just parsed so we can add query parameters to it
        Uri.Builder uriBuilder = baseUri.buildUpon();

        uriBuilder.appendQueryParameter("q", "");
        uriBuilder.appendQueryParameter("format","json");
        uriBuilder.appendQueryParameter("api-key", API_KEY);

        Log.e(LOG_TAG,uriBuilder.toString());

        // Create a new loader for the given URL
        return new ReportLoader(getActivity(), uriBuilder.toString());
    }

    @Override
    public void onLoadFinished(android.support.v4.content.Loader<List<Report>> loader, List<Report> reports) {
        mLoadingIndicator.setVisibility(View.GONE);

        mEmptyStateTextView.setText("No news founded!");

        // Limpa o adapter dos antigos dados de report
        mAdapter.clear();

        // Se há uma lista válida de {@link Report}s, então adiciona-os ao data set do adapter.
        // Isso ativará a atualização da ListView.
        if (reports != null && !reports.isEmpty()) {
            mAdapter.addAll(reports);
        }
    }

    @Override
    public void onLoaderReset(android.support.v4.content.Loader<List<Report>> loader) {
        mAdapter.clear();
    }
}