Enable FilePicker to select multiple files

Good morning, I'm new to Android app programming and I'm wondering how to enable filepicker to select multiple files. My code works, but only selects one file at a time.

Follow the code:

BaseActivity.java

 @Override
    protected void onActivityResult(int reqCode, int resultCode, Intent data) {
        super.onActivityResult(reqCode, resultCode, data);
        if (resultCode == Activity.RESULT_OK) {
            if (reqCode == WebEngine.KEY_FILE_PICKER) {
                String picturePath = FilePicker.getPickedFilePath(this, data);
                if (webEngine != null) {
                    webEngine.uploadFile(data, picturePath);
                }
            }
        }
    }

FilePicker.java

package com.teste.final.utility;
FilePicker.java
import android.content.Context;
import android.content.Intent;
import android.content.pm.ResolveInfo;
import android.database.Cursor;
import android.net.Uri;
import android.os.Environment;
import android.os.Parcelable;
import android.provider.MediaStore;

import java.io.File;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Locale;

/**
 * Created by Ashiq on 6/1/16.
 */

public class FilePicker {

    private static String pictureTempPath = "";
    private static final String CHOOSER_MSG = "Escolha uma opção";
    private static final String IMAGE_PREFIX = "IMG_";
    private static final String IMAGE_EXTENSION = ".jpg";

    /**
     * Start picker intent
     *
     * @param context
     * @return
     */
    public static Intent getPickFileIntent(Context context) {
        Intent chooserIntent = null;

        List<Intent> intentList = new ArrayList<Intent>();
        addIntentsToList(context, intentList, getGalleryIntent());
        addIntentsToList(context, intentList, getCameraIntent(context));
        addIntentsToList(context, intentList, getFileIntent());

        if (intentList.size() > 0) {
            chooserIntent = Intent.createChooser(intentList.remove(intentList.size() - 1), CHOOSER_MSG);
            chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS, intentList.toArray(new Parcelable[]{}));
        }

        return chooserIntent;
    }

    /**
     * Start camera picker intent
     *
     * @param context
     * @return
     */
    public static Intent getCameraPickerIntent(Context context) {
        Intent chooserIntent = null;

        List<Intent> intentList = new ArrayList<Intent>();
        addIntentsToList(context, intentList, getCameraIntent(context));

        if (intentList.size() > 0) {
            chooserIntent = Intent.createChooser(intentList.remove(intentList.size() - 1), CHOOSER_MSG);
            chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS, intentList.toArray(new Parcelable[]{}));
        }

        return chooserIntent;
    }

    /**
     * Start gallery picker intent
     *
     * @param context
     * @return
     */
    public static Intent getGalleryPickerIntent(Context context) {
        Intent chooserIntent = null;

        List<Intent> intentList = new ArrayList<Intent>();
        addIntentsToList(context, intentList, getGalleryIntent());

        if (intentList.size() > 0) {
            chooserIntent = Intent.createChooser(intentList.remove(intentList.size() - 1), CHOOSER_MSG);
            chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS, intentList.toArray(new Parcelable[]{}));
        }

        return chooserIntent;
    }

    /**
     * Get captured image path
     *
     * @param context
     * @param data
     * @return
     */
    public static String getPickedFilePath(Context context, Intent data) {
        String filePath = null;

        boolean isCameraIntent = (data == null || data.getData() == null);

        if (isCameraIntent) {
            filePath = pictureTempPath;
        } else {
            filePath = getImagePath(context, data.getData());
            /*if (filePath == null) {
                filePath = data.getData().getPath();
            }*/
        }

        return filePath;
    }

    private static String getImagePath(Context context, Uri imageUri) {
        String path = null;
        try {
            String[] filePathColumn = {MediaStore.Images.Media.DATA};
            // Get DB Cursor to get Image link
            Cursor cursor = context.getContentResolver().query(imageUri, filePathColumn, null, null, null);
            if (cursor != null && cursor.moveToFirst()) {
                int columnIndex = cursor.getColumnIndex(MediaStore.Images.Media.DATA);
                // Get image path
                path = cursor.getString(columnIndex);
                cursor.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return path;
    }

    /**
     * Creates a gallery intent
     *
     * @return
     */
    private static Intent getGalleryIntent() {
        // Define gallery intent
        return new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
    }

    private static Intent getFileIntent() {
        // Define file intent
        Intent chooseFile = new Intent(Intent.ACTION_GET_CONTENT);
        chooseFile.setType("*/*");
        return chooseFile;
    }


    /**
     * Creates a camera intent
     *
     * @return
     */
    private static Intent getCameraIntent(Context ctx) {
        Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        // Ensure that there's a camera activity to handle the intent
        if (cameraIntent.resolveActivity(ctx.getPackageManager()) != null) {

            cameraIntent.putExtra("return-data", true);

            File path = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM);
            String timeStamp = new SimpleDateFormat(DateUtils.DateTimeFormat.YYMMDD_HHMMSS.toString(), Locale.US).format(new Date());
            String imageFileName = IMAGE_PREFIX + timeStamp;
            File photoFile = new File(path, imageFileName + IMAGE_EXTENSION);

            pictureTempPath = photoFile.getAbsolutePath();

            cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(photoFile));
        }

        return cameraIntent;
    }

    /**
     * Make a list of choices to display to user
     *
     * @param context
     * @param list
     * @param intent
     * @return
     */
    private static void addIntentsToList(Context context, List<Intent> list, Intent intent) {

        List<ResolveInfo> resInfo = context.getPackageManager().queryIntentActivities(intent, 0);
        for (ResolveInfo resolveInfo : resInfo) {
            String packageName = resolveInfo.activityInfo.packageName;
            Intent targetedIntent = new Intent(intent);
            targetedIntent.setPackage(packageName);
            list.add(targetedIntent);
        }
    }
}