Add Lab 3 (Book)

app/build.gradle

@@ -24,6 +24,7 @@ repositories {
 }
 
 dependencies {
+    implementation 'com.android.support:support-annotations:28.0.0'
     implementation fileTree(dir: 'libs', include: ['*.jar'])
     implementation 'androidx.appcompat:appcompat:1.0.0'
     implementation 'androidx.constraintlayout:constraintlayout:1.1.3'

app/src/main/AndroidManifest.xml

@@ -2,8 +2,10 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="ua.kpi.comsys.io8227.jackshen">
 
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
+    <uses-permission android:name="android.permission.INTERNET"/>
 
     <application
         android:allowBackup="true"
@@ -55,6 +57,16 @@
                 <category android:name="android.intent.category.DEFAULT" />
             </intent-filter>
         </activity>
+
+        <activity android:name=".BookActivity"
+            android:theme="@style/Theme.AppCompat.NoActionBar"
+            android:configChanges="orientation|screenSize">
+            <intent-filter>
+                <action android:name="android.intent.action.BookActivity" />
+
+                <category android:name="android.intent.category.DEFAULT" />
+            </intent-filter>
+        </activity>
     </application>
 
 </manifest>

app/src/main/java/ua/kpi/comsys/io8227/jackshen/Book.java

@@ -0,0 +1,67 @@
+package ua.kpi.comsys.io8227.jackshen;
+
+/** An {@link Book} object contains information related to a single book. */
+
+class Book {
+
+    /** Title of the book */
+    private String mTitle;
+
+    /** Subtitle of the book */
+    private String mSubtitle;
+
+    /** ISBN of the book*/
+    private String mIsbn;
+
+    /** Retail price of the book */
+    private String mPrice;
+
+    /** Cover of the book */
+    private String mImageUrl;
+
+    /**
+     * Create book object
+     *
+     * @param title    - title of the book
+     * @param subtitle - subtitle of the book
+     * @param isbn     - isbn number of the book
+     * @param price    - retail price of the book
+     * @param imageUrl - the URL to find cover of the book
+     */
+    Book(String title, String subtitle, String isbn, String price, String imageUrl) {
+        this.mTitle = title;
+        this.mSubtitle = subtitle;
+        this.mIsbn = isbn;
+        this.mPrice = price;
+        this.mImageUrl = imageUrl;
+    }
+
+    /**
+     * Return the title information of the book
+     *
+     * @return the title of the book
+     */
+    String getTitle() {
+        return mTitle;
+    }
+
+    /** Return the subtitle of the book */
+    String getSubtitle() {
+        return mSubtitle;
+    }
+
+    /** Return the ISBN number of the book */
+    String getISBN() {
+        return mIsbn;
+    }
+
+    /** Return the retail price of the book */
+    String getPrice() {
+        return mPrice;
+    }
+
+    /** Return the URL to find cover of the book */
+    String getImageUrl() {
+        return mImageUrl;
+    }
+}

app/src/main/java/ua/kpi/comsys/io8227/jackshen/BookActivity.java

@@ -0,0 +1,123 @@
+package ua.kpi.comsys.io8227.jackshen;
+
+import android.app.LoaderManager;
+import android.content.Context;
+import android.content.Loader;
+import android.net.ConnectivityManager;
+import android.net.NetworkInfo;
+import android.net.Uri;
+import android.os.Build;
+import android.os.Bundle;
+import android.view.View;
+import android.widget.ListView;
+import android.widget.TextView;
+
+import androidx.annotation.RequiresApi;
+import androidx.appcompat.app.AppCompatActivity;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+
+public class BookActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<List<Book>> {
+
+    /** URL for book data */
+    private static final String REQUEST_URL = "https://api.jsonbin.io/b/6023ffbd87173a3d2f5b37e9";
+
+    /**
+     * Constant value for the book loader ID.
+     * We can choose any int, it`s really needed for multiple loaders
+     */
+    private static final int BOOK_LOADER_ID = 1;
+
+    /** Adapter for the list of books */
+    private BookAdapter mAdapter;
+
+    /** TextView that is displayed when the list is empty */
+    private TextView mEmptyTextView;
+
+    @RequiresApi(api = Build.VERSION_CODES.KITKAT)
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        // Initialize activity on main thread.
+        // Bundle holds previous state when re-initialized
+        super.onCreate(savedInstanceState);
+
+        // Inflate the activity's UI
+        setContentView(R.layout.activity_book);
+
+        // Find a reference to the {@link ListView} in the layout
+        ListView bookListView = findViewById(R.id.list);
+
+        // Set empty view when there is no data
+        mEmptyTextView = findViewById(R.id.empty_view);
+        bookListView.setEmptyView(mEmptyTextView);
+
+        // Create a new adapter that takes an empty list of books as input
+        mAdapter = new BookAdapter(this, new ArrayList<Book>());
+
+        // Set the adapter on the {@link ListView} so the list can be populated in UI
+        bookListView.setAdapter(mAdapter);
+
+        // Get a reference to the ConnectivityManager to check state of network connectivity
+        ConnectivityManager connMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
+
+        // Get details on the currently active default data network
+        NetworkInfo networkInfo = Objects.requireNonNull(connMgr).getActiveNetworkInfo();
+
+        // If there is a network connection -> get data
+        if (networkInfo != null && networkInfo.isConnected()) {
+            // Get a reference to the LoaderManager, in order to interact with loaders.
+            LoaderManager loaderManager = getLoaderManager();
+
+            // Get the loader initialized. Go through the above specified int ID constant
+            // and pass the bundle to null.
+            loaderManager.initLoader(BOOK_LOADER_ID, null, this);
+        } else {
+
+            // Otherwise, display error and hide loading indicator so error message will be visible
+            View loadingIndicator = findViewById(R.id.progress_bar);
+            loadingIndicator.setVisibility(View.GONE);
+
+            // Update empty state with no connection error message
+            mEmptyTextView.setText("No internet connection.");
+        }
+    }
+
+    @Override
+    public Loader<List<Book>> onCreateLoader(int i, Bundle bundle) {
+        // Create a new loader for the given URL
+        Uri baseUri = Uri.parse(REQUEST_URL);
+
+        return new BookLoader(this, baseUri.toString());
+    }
+
+    /**
+     * The loader requests and parses information downloader from the internet on a background
+     * thread pool, keeping the UI thread unblocked
+     */
+    @Override
+    public void onLoadFinished(Loader<List<Book>> loader, List<Book> books) {
+
+        // Hide progress bar
+        View loadingIndicator = findViewById(R.id.progress_bar);
+        loadingIndicator.setVisibility(View.GONE);
+
+        // Set empty state text to display "No books to display."
+        mEmptyTextView.setText("No books to display.");
+
+        // Clear the adapter of previous data
+        mAdapter.clear();
+
+        // Add valid list of books to the adapter
+        if (books != null && !books.isEmpty())
+            mAdapter.addAll(books);
+    }
+
+    @Override
+    public void onLoaderReset(Loader<List<Book>> loader) {
+        // Clear existing data on adapter as loader is reset
+        mAdapter.clear();
+    }
+}

app/src/main/java/ua/kpi/comsys/io8227/jackshen/BookAdapter.java

@@ -0,0 +1,119 @@
+package ua.kpi.comsys.io8227.jackshen;
+
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.os.AsyncTask;
+import android.os.Build;
+import android.util.Log;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.ArrayAdapter;
+import android.widget.ImageView;
+import android.widget.TextView;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.RequiresApi;
+
+import java.io.InputStream;
+import java.util.List;
+import java.util.Objects;
+
+
+/**
+ * Class {@link BookAdapter} is used to create a list item layout for each book
+ * in the data source (a list of {@link Book} objects).
+ *
+ * An adapter view such as ListView will be provided with these
+ * list item layouts to be presented to the user.
+ */
+
+public class BookAdapter extends ArrayAdapter<Book> {
+
+    /**
+     * Constructs a new {@link BookAdapter}.
+     *
+     * @param context of the app
+     * @param books - list of books
+     */
+
+    BookAdapter(Context context, List<Book> books) {
+        super(context, 0, books);
+    }
+
+    /**
+     * Returns the view of the list item that shows information about the book in the book list.
+     */
+
+    @RequiresApi(api = Build.VERSION_CODES.KITKAT)
+    @NonNull
+    @Override
+    public View getView(int position, View convertView, @NonNull ViewGroup parent) {
+        // Check if there is an existing convertView that we can reuse, otherwise,
+        // if convertView is null, then inflate a new list item layout.
+        View listItemView = convertView;
+        if (listItemView == null) {
+            listItemView = LayoutInflater.from(getContext()).inflate(R.layout.book_list_item, parent, false);
+        }
+
+        // Find the book at the given position in the list of books
+        Book currentBook = getItem(position);
+
+        // Find the TextView with view ID titleBook
+        TextView titleView = listItemView.findViewById(R.id.titleBook);
+        // Find the TextView with view ID subtitleBook
+        TextView subtitleView = listItemView.findViewById(R.id.subtitleBook);
+        // Find the TextView with view ID isbnBook
+        TextView isbnView = listItemView.findViewById(R.id.isbnBook);
+        // Find the TextView with view ID priceBook
+        TextView priceView = listItemView.findViewById(R.id.priceBook);
+        // Find the ImageView with view ID imageBook
+        ImageView imageView = listItemView.findViewById(R.id.imageBook);
+
+        // Display the title of the current book in that TextView
+        titleView.setText(Objects.requireNonNull(currentBook).getTitle());
+        // Display the subtitle of the current book in that TextView
+        subtitleView.setText(currentBook.getSubtitle());
+        // Display the ISBN of the current book in that TextView
+        isbnView.setText(currentBook.getISBN());
+        // Display the price of the current book in that TextView
+        priceView.setText(currentBook.getPrice());
+
+        // Display image in the ImageView widget
+        if (currentBook.getImageUrl().equals("")) {
+            imageView.setImageResource(R.drawable.noimage);
+        } else {
+            new DownloadImage(imageView).execute(currentBook.getImageUrl());
+        }
+
+        return listItemView;
+    }
+
+    /** Class to download an image from URL */
+    private class DownloadImage extends AsyncTask<String, Void, Bitmap> {
+        final ImageView bmImage;
+
+        DownloadImage(ImageView bmImage) {
+            this.bmImage = bmImage;
+        }
+
+        @RequiresApi(api = Build.VERSION_CODES.KITKAT)
+        protected Bitmap doInBackground(String... urls) {
+            String urlDisplay = urls[0];
+            Bitmap mIcon = null;
+            try {
+                InputStream in = new java.net.URL(urlDisplay).openStream();
+                mIcon = BitmapFactory.decodeStream(in);
+            } catch (Exception e) {
+                Log.e("Error", Objects.requireNonNull(e.getMessage()));
+                e.printStackTrace();
+            }
+            return mIcon;
+        }
+
+        protected void onPostExecute(Bitmap result) {
+            bmImage.setImageBitmap(result);
+        }
+    }
+}