getLoaderManager().initLoader(Id, args, callback);
getLoaderManager().initLoader(0, null, this);

getSupportLoaderManager().initLoader(0, null, this);

public static class StringListLoader 
		extends AsyncTaskLoader<List<String>> {
    
    public StringListLoader(Context context, String queryString) {
       	super(context);
       	mQueryString = queryString;
    }
    
    @Override
    public List<String> loadInBackground() {
        List<String> data = new ArrayList<String>;
        
        // TODO: Muat data dari jaringan atau basis data 
        
        return data;
    }
	
    @Override
    protected void onStartLoading() {  
    	forceLoad();  
    }

}

public class MainActivity extends AppCompatActivity {
	
    ...
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mBookInput = findViewById(R.id.bookInput);
        mTitleText = findViewById(R.id.titleText);
        mAuthorText = findViewById(R.id.authorText);

        if (getSupportLoaderManager().getLoader(0) != null) {
            getSupportLoaderManager().initLoader(0, null, this);
        }
    }
    
    // onCreateLoader
    @Override
    public Loader<List<String>> onCreateLoader(int id, Bundle args) {
        return new StringListLoader(this,args.getString("queryString"));
    }
	
    // Hasil dari pemanggilan metode loadInBackground() disampaikan ke 
    // metode onLoadFinished() ini, di mana Anda dapat menunjukkannya
    // di sini
    @Override
    public void onLoadFinished(Loader<List<String>> loader, List<String> data) {
        mAdapter.setData(data);
    }
    
    // Hanya dipanggil ketika loader dimusnahkan
    @Override 
    public void onLoaderReset(final LoaderList<String>> loader) { 
    	// Biasanya dibiarkan kosong
    }


    ...
}

public class MainActivity extends AppCompatActivity {
	
    ...
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mBookInput = findViewById(R.id.bookInput);
        mTitleText = findViewById(R.id.titleText);
        mAuthorText = findViewById(R.id.authorText);

        if (getSupportLoaderManager().getLoader(0) != null) {
            getSupportLoaderManager().initLoader(0, null, this);
        }
    }
    
    // onCreateLoader
    @Override
    public Loader<List<String>> onCreateLoader(int id, Bundle args) {
        return new StringListLoader(this,args.getString("queryString"));
    }
	
    // Hasil dari pemanggilan metode loadInBackground() disampaikan ke 
    // metode onLoadFinished() ini, di mana Anda dapat menunjukkannya
    // di sini
    @Override
    public void onLoadFinished(Loader<List<String>> loader, List<String> data) {
        mAdapter.setData(data);
    }
    
    // Hanya dipanggil ketika loader dimusnahkan
    @Override 
    public void onLoaderReset(final LoaderList<String>> loader) { 
    	// Biasanya dibiarkan kosong
    }


    ...
}

/*
 * Kelas BookLoader.java
 * Sumber: https://github.com/google-developer-training/android-fundamentals-apps-v2/blob/master/WhoWroteItLoader/app/src/main/java/com/example/android/whowroteitloader/BookLoader.java
 */

package com.example.android.whowroteitloader;

import android.content.Context;
import android.support.annotation.Nullable;
import android.support.v4.content.AsyncTaskLoader;

public class BookLoader extends AsyncTaskLoader<String> {

    private String mQueryString;

    BookLoader(Context context, String queryString) {
        super(context);
        mQueryString = queryString;
    }

    @Override
    protected void onStartLoading() {
        super.onStartLoading();

        forceLoad();
    }

    @Nullable
    @Override
    public String loadInBackground() {
        return NetworkUtils.getBookInfo(mQueryString);
    }
}

/*
 * Kelas MainActivity.java
 * Sumber: https://github.com/google-developer-training/android-fundamentals-apps-v2/blob/master/WhoWroteItLoader/app/src/main/java/com/example/android/whowroteitloader/MainActivity.java
 */

package com.example.android.whowroteitloader;

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.LoaderManager;
import android.support.v4.content.Loader;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.inputmethod.InputMethodManager;
import android.widget.EditText;
import android.widget.TextView;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

/**
 * The WhoWroteIt app queries the Book Search API for books based
 * on a user's search.  It uses an AsyncTask to run the search task in
 * the background.
 */
public class MainActivity extends AppCompatActivity
        implements LoaderManager.LoaderCallbacks<String> {

    private EditText mBookInput;
    private TextView mTitleText;
    private TextView mAuthorText;

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

        mBookInput = findViewById(R.id.bookInput);
        mTitleText = findViewById(R.id.titleText);
        mAuthorText = findViewById(R.id.authorText);

        if (getSupportLoaderManager().getLoader(0) != null) {
            getSupportLoaderManager().initLoader(0, null, this);
        }
    }

    /**
     * onClick handler for the "Search Books" button.
     *
     * @param view The view (Button) that was clicked.
     */
    public void searchBooks(View view) {
        // Get the search string from the input field.
        String queryString = mBookInput.getText().toString();

        // Hide the keyboard when the button is pushed.
        InputMethodManager inputManager = (InputMethodManager)
                getSystemService(Context.INPUT_METHOD_SERVICE);
        if (inputManager != null) {
            inputManager.hideSoftInputFromWindow(view.getWindowToken(),
                    InputMethodManager.HIDE_NOT_ALWAYS);
        }

        // Check the status of the network connection.
        ConnectivityManager connMgr = (ConnectivityManager)
                getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo = null;
        if (connMgr != null) {
            networkInfo = connMgr.getActiveNetworkInfo();
        }

        // If the network is available, connected, and the search field
        // is not empty, start a BookLoader AsyncTask.
        if (networkInfo != null && networkInfo.isConnected()
                && queryString.length() != 0) {

            Bundle queryBundle = new Bundle();
            queryBundle.putString("queryString", queryString);
            getSupportLoaderManager().restartLoader(0, queryBundle, this);

            mAuthorText.setText("");
            mTitleText.setText(R.string.loading);
        }
        // Otherwise update the TextView to tell the user there is no
        // connection, or no search term.
        else {
            if (queryString.length() == 0) {
                mAuthorText.setText("");
                mTitleText.setText(R.string.no_search_term);
            } else {
                mAuthorText.setText("");
                mTitleText.setText(R.string.no_network);
            }
        }
    }


    @NonNull
    @Override
    public Loader<String> onCreateLoader(int id, @Nullable Bundle args) {
        String queryString = "";

        if (args != null) {
            queryString = args.getString("queryString");
        }

        return new BookLoader(this, queryString);
    }

    @Override
    public void onLoadFinished(@NonNull Loader<String> loader, String data) {
        try {
            // Convert the response into a JSON object.
            JSONObject jsonObject = new JSONObject(data);
            // Get the JSONArray of book items.
            JSONArray itemsArray = jsonObject.getJSONArray("items");

            // Initialize iterator and results fields.
            int i = 0;
            String title = null;
            String authors = null;

            // Look for results in the items array, exiting when both the
            // title and author are found or when all items have been checked.
            while (i < itemsArray.length() &&
                    (authors == null && title == null)) {
                // Get the current item information.
                JSONObject book = itemsArray.getJSONObject(i);
                JSONObject volumeInfo = book.getJSONObject("volumeInfo");

                // Try to get the author and title from the current item,
                // catch if either field is empty and move on.
                try {
                    title = volumeInfo.getString("title");
                    authors = volumeInfo.getString("authors");
                } catch (JSONException e) {
                    e.printStackTrace();
                }

                // Move to the next item.
                i++;
            }

            // If both are found, display the result.
            if (title != null && authors != null) {
                mTitleText.setText(title);
                mAuthorText.setText(authors);
                //mBookInput.setText("");
            } else {
                // If none are found, update the UI to show failed results.
                mTitleText.setText(R.string.no_results);
                mAuthorText.setText("");
            }

        } catch (Exception e) {
            // If onPostExecute does not receive a proper JSON string,
            // update the UI to show failed results.
            mTitleText.setText(R.string.no_results);
            mAuthorText.setText("");
            e.printStackTrace();
        }

    }

    @Override
    public void onLoaderReset(@NonNull Loader<String> loader) {
        // Do nothing.  Required by interface.
    }
}