Pick multiple images from gallery OR Custom gallery

import android.content.ClipData;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Parcelable;
import android.provider.MediaStore;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.ClipboardManager;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;

import java.util.ArrayList;

import static android.R.attr.action;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    Button camera,gallery;
    private LinearLayout lnrImages;
    private Button btnAddPhots;
    private Button btnSaveImages;
    private ArrayList<String> imagesPathList;
    private Bitmap yourbitmap;
    private Bitmap resized;
    private final int PICK_IMAGE_MULTIPLE =1;

private final int SELECT_PHOTO =2;
private ArrayList<String>photos;
@Override    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        camera = (Button) findViewById(R.id.camera);
        gallery = (Button) findViewById(R.id.gallery);

        camera.setOnClickListener(this);
        gallery.setOnClickListener(this);
    }

    @Override    public void onClick(View v) {
        if(v == camera){          
Intent photoPickerIntent = new Intent(Intent.ACTION_PICK);
photoPickerIntent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true);

photoPickerIntent.setType("image/*");
startActivityForResult(photoPickerIntent, SELECT_PHOTO);
}
        if(v == gallery){
            Intent intent = new Intent(MainActivity.this,CustomPhotoGalleryActivity.class);
            startActivityForResult(intent,PICK_IMAGE_MULTIPLE);
        }
    }

    public String getRealPathFromURI(Context context, Uri contentUri) {
        Cursor cursor = null;
        try {
            String[] proj = { MediaStore.Images.Media.DATA };
            cursor = context.getContentResolver().query(contentUri, proj, null,
                    null, null);
            int column_index = cursor
                    .getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
            cursor.moveToFirst();
            return cursor.getString(column_index);
        } finally {
            if (cursor != null) {
                cursor.close();
            }
        }
    }

@Overrideprotected void onActivityResult(int requestCode, int resultCode, Intent imageReturnedIntent) {
    super.onActivityResult(requestCode, resultCode, imageReturnedIntent);

    switch (requestCode) {
        case SELECT_PHOTO:
            if (resultCode == RESULT_OK) {
                if (imageReturnedIntent.getData() != null) {
                    //If uploaded with Android Gallery (max 1 image)                    Uri selectedImage = imageReturnedIntent.getData();
                    InputStream imageStream;
                    try {
                        imageStream = getContentResolver().openInputStream(selectedImage);
                        Bitmap yourSelectedImage = BitmapFactory.decodeStream(imageStream);
                      //  photos.add(String.valueOf(yourSelectedImage));                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    }
                } else {
                    //If uploaded with the new Android Photos gallery                    ClipData clipData = imageReturnedIntent.getClipData();
                    for (int i = 0; i < clipData.getItemCount(); i++) {
                        clipData.getItemAt(i);
                        Log.e("imahe",clipData.getItemAt(i)+"");
                        //What now?                    }
                }
            }
            break;
    }
}
}

---------------------------****---------------------------------

Layout =  activity_main

<?xml version="1.0" encoding="utf-8"?><android.support.constraint.ConstraintLayout 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"    tools:context="com.nagraj.customiamge.MainActivity"    tools:layout_editor_absoluteY="81dp"    tools:layout_editor_absoluteX="0dp">

    
    <LinearLayout        android:layout_width="368dp"        android:layout_height="wrap_content"        tools:layout_editor_absoluteY="0dp"        tools:layout_editor_absoluteX="8dp"       >
        <LinearLayout            android:layout_width="match_parent"            android:layout_height="match_parent"            android:orientation="vertical">
            <Button                android:id="@+id/camera"                android:layout_width="match_parent"                android:layout_height="wrap_content"                android:text="Camera"/>

            <Button                android:id="@+id/gallery"                android:layout_width="match_parent"                android:layout_height="wrap_content"                android:text="gallery"/>
        </LinearLayout>

    </LinearLayout>

</android.support.constraint.ConstraintLayout>

----------------------------------*****-----------------------------------------
CALSS =  CustomPhotoGalleryActivity 

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.os.AsyncTask;
import android.os.Bundle;
import android.provider.MediaStore;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.Toast;

/** * Created by Nagraj on 5/18/2017. */
class CustomPhotoGalleryActivity extends Activity {

    private GridView grdImages;
    private Button btnSelect;

    private ImageAdapter imageAdapter;
    private String[] arrPath;
    private boolean[] thumbnailsselection;
    private int ids[];
    private int count;


    /**     * Overrides methods     */    @Override    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.custom_gallery);
        grdImages= (GridView) findViewById(R.id.grdImages);
        btnSelect= (Button) findViewById(R.id.btnSelect);

        final String[] columns = { MediaStore.Images.Media.DATA, MediaStore.Images.Media._ID };
        final String orderBy = MediaStore.Images.Media._ID;
        @SuppressWarnings("deprecation")
        Cursor imagecursor = managedQuery(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, columns, null, null, orderBy);
        int image_column_index = imagecursor.getColumnIndex(MediaStore.Images.Media._ID);
        this.count = imagecursor.getCount();
        this.arrPath = new String[this.count];
        ids = new int[count];
        this.thumbnailsselection = new boolean[this.count];
        for (int i = 0; i < this.count; i++) {
            imagecursor.moveToPosition(i);
            ids[i] = imagecursor.getInt(image_column_index);
            int dataColumnIndex = imagecursor.getColumnIndex(MediaStore.Images.Media.DATA);
            arrPath[i] = imagecursor.getString(dataColumnIndex);
        }

        imageAdapter = new ImageAdapter();
        grdImages.setAdapter(imageAdapter);
        imagecursor.close();


        btnSelect.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {
                final int len = thumbnailsselection.length;
                int cnt = 0;
                String selectImages = "";
                for (int i = 0; i < len; i++) {
                    if (thumbnailsselection[i]) {
                        cnt++;
                        selectImages = selectImages + arrPath[i] + "|";
                    }
                }
                if (cnt == 0) {
                    Toast.makeText(getApplicationContext(), "Please select at least one image", Toast.LENGTH_LONG).show();
                } else {

                    Log.d("SelectedImages", selectImages);
                    Intent i = new Intent();
                    i.putExtra("data", selectImages);
                    setResult(Activity.RESULT_OK, i);
                    finish();
                }
            }
        });
    }
    @Override    public void onBackPressed() {
        setResult(Activity.RESULT_CANCELED);
        super.onBackPressed();

    }

    /**     * Class method     */
    /**     * This method used to set bitmap.     * @param iv represented ImageView     * @param id represented id     */
    private void setBitmap(final ImageView iv, final int id) {

        new AsyncTask<Void, Void, Bitmap>() {

            @Override            protected Bitmap doInBackground(Void... params) {
                return MediaStore.Images.Thumbnails.getThumbnail(getApplicationContext().getContentResolver(), id, MediaStore.Images.Thumbnails.MICRO_KIND, null);
            }

            @Override            protected void onPostExecute(Bitmap result) {
                super.onPostExecute(result);
                iv.setImageBitmap(result);
            }
        }.execute();
    }


    /**     * List adapter     * @author tasol     */
    public class ImageAdapter extends BaseAdapter {
        private LayoutInflater mInflater;

        public ImageAdapter() {
            mInflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        }

        public int getCount() {
            return count;
        }

        public Object getItem(int position) {
            return position;
        }

        public long getItemId(int position) {
            return position;
        }

        public View getView(int position, View convertView, ViewGroup parent) {
            final ViewHolder holder;
            if (convertView == null) {
                holder = new ViewHolder();
                convertView = mInflater.inflate(R.layout.custom_gallery_item, null);
                holder.imgThumb = (ImageView) convertView.findViewById(R.id.imgThumb);
                holder.chkImage = (CheckBox) convertView.findViewById(R.id.chkImage);

                convertView.setTag(holder);
            } else {
                holder = (ViewHolder) convertView.getTag();
            }
            holder.chkImage.setId(position);
            holder.imgThumb.setId(position);
            holder.chkImage.setOnClickListener(new View.OnClickListener() {

                public void onClick(View v) {
                    CheckBox cb = (CheckBox) v;
                    int id = cb.getId();
                    if (thumbnailsselection[id]) {
                        cb.setChecked(false);
                        thumbnailsselection[id] = false;
                    } else {
                        cb.setChecked(true);
                        thumbnailsselection[id] = true;
                    }
                }
            });
            holder.imgThumb.setOnClickListener(new View.OnClickListener() {

                public void onClick(View v) {
                    int id = holder.chkImage.getId();
                    if (thumbnailsselection[id]) {
                        holder.chkImage.setChecked(false);
                        thumbnailsselection[id] = false;
                    } else {
                        holder.chkImage.setChecked(true);
                        thumbnailsselection[id] = true;
                    }
                }
            });
            try {
                setBitmap(holder.imgThumb, ids[position]);
            } catch (Throwable e) {
            }
            holder.chkImage.setChecked(thumbnailsselection[position]);
            holder.id = position;
            return convertView;
        }
    }


    /**     * Inner class     * @author tasol     */    class ViewHolder {
        ImageView imgThumb;
        CheckBox chkImage;
        int id;
    }


}

-----------------------**********--------------------------------

LAYOUT  :=   custom_gallery_item

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    >
    <LinearLayout        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:orientation="vertical">
        <ImageView            android:id="@+id/imgThumb"            android:layout_width="match_parent"            android:layout_height="match_parent"/>

        <CheckBox            android:id="@+id/chkImage"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_gravity="top|right"/>
    </LinearLayout>

</LinearLayout>


--------------------------***************------------------------
Layout := custom_gallery


<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"        android:layout_width="match_parent"        android:layout_height="match_parent"        android:gravity="center"        android:orientation="vertical">
        <GridView            android:id="@+id/grdImages"            android:layout_width="match_parent"            android:layout_height="0dp"            android:layout_weight="1"            android:numColumns="auto_fit"            android:verticalSpacing="10dp"            android:horizontalSpacing="10dp"            android:columnWidth="90dp"            android:stretchMode="columnWidth"            android:gravity="center"/>

        <Button            android:id="@+id/btnSelect"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="Select"            android:layout_marginTop="5dp"/>

    </LinearLayout>
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