InstallLocation for Android

  InstallLocation for Android

    If you declare "preferExternal", you request that your application be installed on the external storage, but the system does not guarantee that your application will be installed on the external storage. If the external storage is full, the system will install it on the internal storage. The user can also move your application between the two locations.

      If you declare "auto", you indicate that your application may be installed on the external storage, but you don't have a preference of install location. The system will decide where to install your application based on several factors. The user can also move your application between the two locations.

android:installLocation="auto" or // "preferExternal"
    android:versionCode="1"
    android:versionName="1.0"

Scan barcode from an image in gallery android form Fragment

I have a working sample on how to implement this

/**
 * Created by shashi kumar on 12/14/2016.
 */
public class Main2Activity extends Fragment {
    private ImageView barcodeImageView;
    private Button pickBarcodeButton;
    private TextView barcodeResultTextView;
    Context ctx;
    private String result = "";

    protected static final int PICK_IMAGE_REQUEST = 100;




   /* @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);

        initializeViews();

    }*/




    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        ctx = this.getContext();

        View rootView = inflater.inflate(R.layout.activity_main2, container, false);

        barcodeImageView = (ImageView) rootView.findViewById(R.id.barcode_image);
        pickBarcodeButton = (Button) rootView.findViewById(R.id.pick_barcode_btn);
//        barcodeResultTextView = (TextView) rootView.findViewById(R.id.barcode_result_txtview);
//        showBackButton();

        ((AppMain) getActivity()).getSupportActionBar().setTitle("Help");

        initializeViews();
        return rootView;

    }

    private void initializeViews() {
      /*  barcodeImageView = (ImageView) rootView.findViewById(R.id.barcode_image);
        pickBarcodeButton = (Button) findViewById(R.id.pick_barcode_btn);
        barcodeResultTextView = (TextView) findViewById(R.id.barcode_result_txtview);*/

        pickBarcodeButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
               /* Intent intent = new Intent();
                intent.setType("image*//*");
                intent.setAction(Intent.ACTION_GET_CONTENT);
                startActivityForResult(Intent.createChooser(intent, "Select Picture"), PICK_IMAGE_REQUEST);*/


                Intent photoPic = new Intent(Intent.ACTION_PICK);
                photoPic.setType("image/*");
                startActivityForResult(photoPic, PICK_IMAGE_REQUEST);

            }
        });
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if(requestCode == PICK_IMAGE_REQUEST){

            if (resultCode == RESULT_OK) {

                if (data != null && data.getData() != null) {
                    Uri uri = data.getData();

                    try {
                        Bitmap bitmap = MediaStore.Images.Media.getBitmap(ctx.getContentResolver(), uri);
                        new ScanTask(bitmap).execute();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    }

    /**
     * @author dipenp
     * AsyncTask to scan barcode in background.
     */
    class ScanTask extends AsyncTask<String, String, String> {

        private Bitmap bitmap;


        public ScanTask(Bitmap bitmap) {
            this.bitmap = bitmap;
        }



        @Override
        protected String doInBackground(String... params) {
            try {

                Result[] results = decode(bitmap);

                if (null != results) {
                    for (int i = 0; i < results.length; i++) {
                        result = result +" ("+(i+1)+") "+ results[i].getText() + "\n";
                    }

                } else {
                    result = "No result found:::";
                }
            } catch (Exception e) {
                result = "Exception";
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(String res) {
//            barcodeResultTextView.setText(result);
            DialogShow();
            super.onPostExecute(res);
        }

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            barcodeImageView.setImageBitmap(bitmap);
        }
    }

    /**
     * @param imageBitmap : Bitmap image
     * @return Array of barcode result
     */
    public Result[] decode(Bitmap imageBitmap) {

        MultiFormatReader reader = null;
        Map<DecodeHintType, Object> hints = new EnumMap<DecodeHintType, Object>(DecodeHintType.class);

  /* There are different format to create barcode and qrcode,
   * while extracting we are adding all the possible format for better result.
   */
        hints.put(DecodeHintType.POSSIBLE_FORMATS, EnumSet.allOf(BarcodeFormat.class));
        hints.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);

        reader = new MultiFormatReader();
        reader.setHints(hints);

        int width = imageBitmap.getWidth();
        int height = imageBitmap.getHeight();
        int[] pixels = new int[width * height];
        imageBitmap.getPixels(pixels, 0, width, 0, 0, width, height);

        RGBLuminanceSource source = new RGBLuminanceSource(width, height, pixels);
        BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));

        MultipleBarcodeReader multiReader = new GenericMultipleBarcodeReader(reader);
        Result[] theResults = null;
        try {
   /* decode multiple is used so that if multiple barcode is present in single image we can get result for all of them.
    */
            theResults = multiReader.decodeMultiple(bitmap, hints);
        } catch (NotFoundException e1) {
            e1.printStackTrace();
        }

        return theResults;
    }

    protected void DialogShow() {

        android.app.AlertDialog.Builder builder = new android.app.AlertDialog.Builder(ctx);
        builder.setTitle("Confirmation?");
        //builder.setIcon( R.drawable.ic_local_offer_black_24dp );
        builder.setCancelable(false);
        builder.setMessage(result);

        builder.setNegativeButton("Share", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int whichButton) {
                final Intent shareIntent = new Intent(Intent.ACTION_SEND);
                shareIntent.setType("text/plain");
                shareIntent.putExtra(android.content.Intent.EXTRA_TEXT, result);
                getContext().startActivity(Intent.createChooser(shareIntent, "Share text"));
            }
        });

        builder.setNeutralButton("Cancel", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int whichButton) {
                dialog.dismiss();
            }
        });

        // create an alert dialog
        android.app.AlertDialog alert = builder.create();
        alert.show();
    }

}

Scan barcode from an image in gallery android

Scan barcode from an image in gallery android

You could use this class MultiFormatReader from ZXing library.

You have to get Gallery image in BitMap and convert it as this

Bitmap bMap = [...];

String contents = null;

int[] intArray = new int[bMap.getWidth()*bMap.getHeight()]; 

//copy pixel data from the Bitmap into the 'intArray' array 

bMap.getPixels(intArray, 0, bMap.getWidth(), 0, 0, bMap.getWidth(), bMap.getHeight()); 

LuminanceSource source = new RGBLuminanceSource(bMap.getWidth(), bMap.getHeight(), intArray);

BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));

Reader reader = new MultiFormatReader();

Result result = reader.decode(bitmap);

contents = result.getText();

Android working with Card View and Recycler View

 CardView is another major element introduced in Material Design. Using CardView you can represent the information in a card manner with a drop shadow (elevation) and corner radius which looks consistent across the platform.

How to Add CardView?

To use the CardView in your app, add the CardView dependency in build.gradle and Sync the project.

dependencies {
    // CardView
    compile 'com.android.support:cardview-v7:23.3.+'
}

Add the <android.support.v7.widget.CardView> widget to your layout and place other UI widgets like TextViews, ImageViews inside it. You can notice that the below CardView widget contains a single TextView.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:card_view="http://schemas.android.com/apk/res-auto">

    <android.support.v7.widget.CardView
        xmlns:card_view="http://schemas.android.com/apk/res-auto"
        android:id="@+id/card_view"
        android:layout_gravity="center"
        android:layout_width="250dp"
        android:layout_height="250dp"
        card_view:cardCornerRadius="4dp">

        <TextView
            android:text="Hello Card"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />

    </android.support.v7.widget.CardView>

</LinearLayout>

Creating New Project.

Create a new project in Android Studio from File New Project. When it prompts you to select the default activity, select Empty Activity and proceed.

Add album covers and icons required for this project.

Add the below strings, colors and dimen resources to strings.xml, colors.xml and dimens.xml files.

<resources>
    <string name="app_name">Card View</string>
    <string name="action_settings">Settings</string>
    <string name="action_add_favourite">Add to Favourites</string>
    <string name="action_play_next">Play Next</string>
    <string name="backdrop_title">LOVE MUSIC</string>
    <string name="backdrop_subtitle">This season top 20 albums</string>
</resources>

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="colorPrimary">#F50057</color>
    <color name="colorPrimaryDark">#F50057</color>
    <color name="colorAccent">#FF4081</color>
    <color name="viewBg">#f1f5f8</color>
    <color name="album_title">#4c4c4c</color>
</resources>  

<resources>
    <dimen name="activity_horizontal_margin">16dp</dimen>
    <dimen name="activity_vertical_margin">16dp</dimen>
    <dimen name="fab_margin">16dp</dimen>
    <dimen name="item_offset">10dp</dimen>
    <dimen name="detail_backdrop_height">250dp</dimen>
    <dimen name="backdrop_title">30dp</dimen>
    <dimen name="backdrop_subtitle">18dp</dimen>
    <dimen name="card_margin">5dp</dimen>
    <dimen name="card_album_radius">0dp</dimen>
    <dimen name="album_cover_height">160dp</dimen>
    <dimen name="album_title_padding">10dp</dimen>
    <dimen name="album_title">15dp</dimen>
    <dimen name="songs_count_padding_bottom">5dp</dimen>
    <dimen name="songs_count">12dp</dimen>
    <dimen name="ic_album_overflow_width">20dp</dimen>
    <dimen name="ic_album_overflow_height">30dp</dimen>
    <dimen name="ic_album_overflow_margin_top">10dp</dimen>
</resources>

Open build.gradle and add CardView, RecyclerView and Glide dependencies. RecyclerView is used to display the albums in grid manner. CardView is used to display single album item. Glide is used to display the album cover images.

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.3.0'
    compile 'com.android.support:design:23.3.0'

    // RecyclerView
    compile 'com.android.support:recyclerview-v7:23.3.+'

    // CardView
    compile 'com.android.support:cardview-v7:23.3.+'

    // Glide
    compile 'com.github.bumptech.glide:glide:3.7.0'
}

 To create instance of a single album, we need a model class denoting the album properties like name, number of songs and cover image. So create a class named Album.java and add the below code.

package com.singh.cardview;

/**
 * Created by Singh on 20/11/16.
 */
public class Album {
    private String name;
    private int numOfSongs;
    private int thumbnail;

    public Album() {
    }

    public Album(String name, int numOfSongs, int thumbnail) {
        this.name = name;
        this.numOfSongs = numOfSongs;
        this.thumbnail = thumbnail;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getNumOfSongs() {
        return numOfSongs;
    }

    public void setNumOfSongs(int numOfSongs) {
        this.numOfSongs = numOfSongs;
    }

    public int getThumbnail() {
        return thumbnail;
    }

    public void setThumbnail(int thumbnail) {
        this.thumbnail = thumbnail;
    }
}

We also need an xml layout to display the album card. Create an xml layout named album_card.xml under res layout. Here you can notice that I have added <android.support.v7.widget.CardView> and added all the album properties like name, number of songs and cover image inside it. I also added a 3 dot icon which shows a popup menu on tapping it.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <android.support.v7.widget.CardView
        android:id="@+id/card_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_gravity="center"
        android:layout_margin="@dimen/card_margin"
        android:elevation="3dp"
        card_view:cardCornerRadius="@dimen/card_album_radius">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <ImageView
                android:id="@+id/thumbnail"
                android:layout_width="match_parent"
                android:layout_height="@dimen/album_cover_height"
                android:background="?attr/selectableItemBackgroundBorderless"
                android:clickable="true"
                android:scaleType="fitXY" />

            <TextView
                android:id="@+id/title"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@id/thumbnail"
                android:paddingLeft="@dimen/album_title_padding"
                android:paddingRight="@dimen/album_title_padding"
                android:paddingTop="@dimen/album_title_padding"
                android:textColor="@color/album_title"
                android:textSize="@dimen/album_title" />

            <TextView
                android:id="@+id/count"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_below="@id/title"
                android:paddingBottom="@dimen/songs_count_padding_bottom"
                android:paddingLeft="@dimen/album_title_padding"
                android:paddingRight="@dimen/album_title_padding"
                android:textSize="@dimen/songs_count" />

            <ImageView
                android:id="@+id/overflow"
                android:layout_width="@dimen/ic_album_overflow_width"
                android:layout_height="@dimen/ic_album_overflow_height"
                android:layout_alignParentRight="true"
                android:layout_below="@id/thumbnail"
                android:layout_marginTop="@dimen/ic_album_overflow_margin_top"
                android:scaleType="centerCrop"
                android:src="@drawable/ic_dots" />

        </RelativeLayout>

    </android.support.v7.widget.CardView>

</LinearLayout>

Create a menu file named menu_album.xml under res  menu folder. This menu will be shown as popup menu on tapping on dots icons on each album card item.

<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools">
    <item
        android:id="@+id/action_add_favourite"
        android:orderInCategory="100"
        android:title="@string/action_add_favourite" />

    <item
        android:id="@+id/action_play_next"
        android:orderInCategory="101"
        android:title="@string/action_play_next" />
</menu>

To render the RecyclerView, we need an adapter class which inflates the album_card.xml by keeping appropriate information. Create a class named AlbumsAdapter.java and add the below content.

package com.singh.cardview;

import android.content.Context;
import android.support.v7.widget.PopupMenu;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

import com.bumptech.glide.Glide;

import java.util.List;

/**
 * Created by Singh on 20/11/16.
 */
public class AlbumsAdapter extends RecyclerView.Adapter<AlbumsAdapter.MyViewHolder> {

    private Context mContext;
    private List<Album> albumList;

    public class MyViewHolder extends RecyclerView.ViewHolder {
        public TextView title, count;
        public ImageView thumbnail, overflow;

        public MyViewHolder(View view) {
            super(view);
            title = (TextView) view.findViewById(R.id.title);
            count = (TextView) view.findViewById(R.id.count);
            thumbnail = (ImageView) view.findViewById(R.id.thumbnail);
            overflow = (ImageView) view.findViewById(R.id.overflow);
        }
    }


    public AlbumsAdapter(Context mContext, List<Album> albumList) {
        this.mContext = mContext;
        this.albumList = albumList;
    }

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

        return new MyViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(final MyViewHolder holder, int position) {
        Album album = albumList.get(position);
        holder.title.setText(album.getName());
        holder.count.setText(album.getNumOfSongs() + " songs");

        // loading album cover using Glide library
        Glide.with(mContext).load(album.getThumbnail()).into(holder.thumbnail);

        holder.overflow.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                showPopupMenu(holder.overflow);
            }
        });
    }

  
    private void showPopupMenu(View view) {
        // inflate menu
        PopupMenu popup = new PopupMenu(mContext, view);
        MenuInflater inflater = popup.getMenuInflater();
        inflater.inflate(R.menu.menu_album, popup.getMenu());
        popup.setOnMenuItemClickListener(new MyMenuItemClickListener());
        popup.show();
    }

    /**
     * Click listener for popup menu items
     */
    class MyMenuItemClickListener implements PopupMenu.OnMenuItemClickListener {

        public MyMenuItemClickListener() {
        }

        @Override
        public boolean onMenuItemClick(MenuItem menuItem) {
            switch (menuItem.getItemId()) {
                case R.id.action_add_favourite:
                    Toast.makeText(mContext, "Add to favourite", Toast.LENGTH_SHORT).show();
                    return true;
                case R.id.action_play_next:
                    Toast.makeText(mContext, "Play next", Toast.LENGTH_SHORT).show();
                    return true;
                default:
            }
            return false;
        }
    }

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

Open the layout files main activity activity_main.xml and content_main.xml, add AppBarLayout, CollapsingToolbarLayout, Toolbar and RecyclerView.

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/main_content"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/white"
    android:fitsSystemWindows="true">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appbar"
        android:layout_width="match_parent"
        android:layout_height="@dimen/detail_backdrop_height"
        android:fitsSystemWindows="true"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

        <android.support.design.widget.CollapsingToolbarLayout
            android:id="@+id/collapsing_toolbar"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:fitsSystemWindows="true"
            app:contentScrim="?attr/colorPrimary"
            app:expandedTitleMarginEnd="64dp"
            app:expandedTitleMarginStart="48dp"
            app:expandedTitleTextAppearance="@android:color/transparent"
            app:layout_scrollFlags="scroll|exitUntilCollapsed">

            <RelativeLayout
                android:layout_width="wrap_content"
                android:layout_height="wrap_content">

                <ImageView
                    android:id="@+id/backdrop"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:fitsSystemWindows="true"
                    android:scaleType="centerCrop"
                    app:layout_collapseMode="parallax" />

                <LinearLayout
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_centerInParent="true"
                    android:gravity="center_horizontal"
                    android:orientation="vertical">

                    <TextView
                        android:id="@+id/love_music"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:text="@string/backdrop_title"
                        android:textColor="@android:color/white"
                        android:textSize="@dimen/backdrop_title" />

                    <TextView
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:text="@string/backdrop_subtitle"
                        android:textColor="@android:color/white"
                        android:textSize="@dimen/backdrop_subtitle" />

                </LinearLayout>
            </RelativeLayout>

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                app:layout_collapseMode="pin"
                app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />

        </android.support.design.widget.CollapsingToolbarLayout>

    </android.support.design.widget.AppBarLayout>

    <include layout="@layout/content_main" />

</android.support.design.widget.CoordinatorLayout>

content_main.xml

?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/viewBg"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="info.androidhive.cardview.MainActivity"
    tools:showIn="@layout/activity_main">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:clipToPadding="false"
        android:scrollbars="vertical" />

</RelativeLayout>

Finally open MainActivity.java and do the necessary changes.

 initCollapsingToolbar()  Shows or hides the toolbar title when the toolbar is collapsed or expanded.

 prepareAlbums()  Adds sample albums data required for the recycler view.

 GridLayoutManager is used to display the RecyclerView in Grid manner instead of list.

GridSpacingItemDecoration is used to give equal margins around RecyclerView grid items.

AlbumsAdapter instance is created and assigned to RecyclerView which renders the CardView albums in grid fashion.

package com.singh.cardview;

import android.content.res.Resources;
import android.graphics.Rect;
import android.os.Bundle;
import android.support.design.widget.AppBarLayout;
import android.support.design.widget.CollapsingToolbarLayout;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.util.TypedValue;
import android.view.View;
import android.widget.ImageView;

import com.bumptech.glide.Glide;

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

public class MainActivity extends AppCompatActivity {

    private RecyclerView recyclerView;
    private AlbumsAdapter adapter;
    private List<Album> albumList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        initCollapsingToolbar();

        recyclerView = (RecyclerView) findViewById(R.id.recycler_view);

        albumList = new ArrayList<>();
        adapter = new AlbumsAdapter(this, albumList);

        RecyclerView.LayoutManager mLayoutManager = new GridLayoutManager(this, 2);
        recyclerView.setLayoutManager(mLayoutManager);
        recyclerView.addItemDecoration(new GridSpacingItemDecoration(2, dpToPx(10), true));
        recyclerView.setItemAnimator(new DefaultItemAnimator());
        recyclerView.setAdapter(adapter);

        prepareAlbums();

        try {
            Glide.with(this).load(R.drawable.cover).into((ImageView) findViewById(R.id.backdrop));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

  
    private void initCollapsingToolbar() {
        final CollapsingToolbarLayout collapsingToolbar =
                (CollapsingToolbarLayout) findViewById(R.id.collapsing_toolbar);
        collapsingToolbar.setTitle(" ");
        AppBarLayout appBarLayout = (AppBarLayout) findViewById(R.id.appbar);
        appBarLayout.setExpanded(true);

        // hiding & showing the title when toolbar expanded & collapsed
        appBarLayout.addOnOffsetChangedListener(new AppBarLayout.OnOffsetChangedListener() {
            boolean isShow = false;
            int scrollRange = -1;

            @Override
            public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {
                if (scrollRange == -1) {
                    scrollRange = appBarLayout.getTotalScrollRange();
                }
                if (scrollRange + verticalOffset == 0) {
                    collapsingToolbar.setTitle(getString(R.string.app_name));
                    isShow = true;
                } else if (isShow) {
                    collapsingToolbar.setTitle(" ");
                    isShow = false;
                }
            }
        });
    }

    /**
     * Adding albums for testing
     */
    private void prepareAlbums() {
        int[] covers = new int[]{
                R.drawable.album1,
                R.drawable.album2,
                R.drawable.album3,
                R.drawable.album4,
                R.drawable.album5,
                R.drawable.album6};

        Album a = new Album("Album", 6, covers[0]);
        albumList.add(a);

        a = new Album("Album", 10, covers[1]);
        albumList.add(a);

        a = new Album("Album", 4, covers[2]);
        albumList.add(a);

        a = new Album("Album", 2, covers[3]);
        albumList.add(a);

        a = new Album("Album", 11, covers[4]);
        albumList.add(a);

        a = new Album("Album", 9, covers[5]);
        albumList.add(a);

       
        adapter.notifyDataSetChanged();
    }

    /**
     * RecyclerView item decoration - give equal margin around grid item
     */
    public class GridSpacingItemDecoration extends RecyclerView.ItemDecoration {

        private int spanCount;
        private int spacing;
        private boolean includeEdge;

        public GridSpacingItemDecoration(int spanCount, int spacing, boolean includeEdge) {
            this.spanCount = spanCount;
            this.spacing = spacing;
            this.includeEdge = includeEdge;
        }

        @Override
        public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
            int position = parent.getChildAdapterPosition(view); // item position
            int column = position % spanCount; // item column

            if (includeEdge) {
                outRect.left = spacing - column * spacing / spanCount; // spacing - column * ((1f / spanCount) * spacing)
                outRect.right = (column + 1) * spacing / spanCount; // (column + 1) * ((1f / spanCount) * spacing)

                if (position < spanCount) { // top edge
                    outRect.top = spacing;
                }
                outRect.bottom = spacing; // item bottom
            } else {
                outRect.left = column * spacing / spanCount; // column * ((1f / spanCount) * spacing)
                outRect.right = spacing - (column + 1) * spacing / spanCount; // spacing - (column + 1) * ((1f /    spanCount) * spacing)
                if (position >= spanCount) {
                    outRect.top = spacing; // item top
                }
            }
        }
    }

    /**
     * Converting dp to pixel
     */
    private int dpToPx(int dp) {
        Resources r = getResources();
        return Math.round(TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp, r.getDisplayMetrics()));
    }
}