"Drag and swipe with RecyclerView" files

fragment_main.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  ~ Copyright (C) 2015 Paul Burke
  ~
  ~ Licensed under the Apache License, Version 2.0 (the "License");
  ~ you may not use this file except in compliance with the License.
  ~ You may obtain a copy of the License at
  ~
  ~      http://www.apache.org/licenses/LICENSE-2.0
  ~
  ~ Unless required by applicable law or agreed to in writing, software
  ~ distributed under the License is distributed on an "AS IS" BASIS,
  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  ~ See the License for the specific language governing permissions and
  ~ limitations under the License.
  -->
<android.support.v7.widget.RecyclerView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/recycler_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

item_main.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  ~ Copyright (C) 2015 Paul Burke
  ~
  ~ Licensed under the Apache License, Version 2.0 (the "License");
  ~ you may not use this file except in compliance with the License.
  ~ You may obtain a copy of the License at
  ~
  ~      http://www.apache.org/licenses/LICENSE-2.0
  ~
  ~ Unless required by applicable law or agreed to in writing, software
  ~ distributed under the License is distributed on an "AS IS" BASIS,
  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  ~ See the License for the specific language governing permissions and
  ~ limitations under the License.
  -->
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/text"
    android:layout_width="wrap_content"
    android:layout_height="?listPreferredItemHeight"
    android:layout_gravity="center_vertical"
    android:paddingLeft="16dp"
    android:textAppearance="?android:attr/textAppearanceMedium" />

ItemViewHolder.java

/*
 * Copyright (C) 2015 Paul Burke
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
import android.support.v7.widget.RecyclerView;
import android.widget.TextView;

public class ItemViewHolder extends RecyclerView.ViewHolder {

    public final TextView textView;

    public ItemViewHolder(View itemView) {
        super(itemView);
        textView = (TextView) itemView;
    }
    
}

MainFragment.java

/*
 * Copyright (C) 2015 Paul Burke
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class MainFragment extends Fragment {

    public MainFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_main, container, false);
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        RecyclerView recyclerView = (RecyclerView) view.findViewById(R.id.recycler_view);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
        
        RecyclerListAdapter adapter = new RecyclerListAdapter();
        recyclerView.setAdapter(adapter);
    }
}

RecyclerListAdapter.java

/*
 * Copyright (C) 2015 Paul Burke
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

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

public class RecyclerListAdapter extends RecyclerView.Adapter<ItemViewHolder> {

    private static final String[] STRINGS = new String[]{
            "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten"
    };

    private final List<String> mItems = new ArrayList<>();

    public RecyclerListAdapter() {
        mItems.addAll(Arrays.asList(STRINGS));
    }

    @Override
    public ItemViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_main, parent, false);
        return new ItemViewHolder(view);
    }

    @Override
    public void onBindViewHolder(ItemViewHolder holder, int position) {
        holder.textView.setText(mItems.get(position));
    }

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

}

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/text"
    android:layout_width="wrap_content"
    android:layout_height="?listPreferredItemHeight"
    android:layout_gravity="center_vertical"
    android:paddingStart="16dp"
    android:textAppearance="?android:attr/textAppearanceMedium" />

package com.example.dragndropgrid

import android.view.View
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView.ViewHolder


class ItemViewHolder(itemView: View) : ViewHolder(itemView) {
    val textView: TextView? = itemView as? TextView

}

package com.example.dragndropgrid

import android.os.Bundle
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.fragment.app.Fragment
import androidx.recyclerview.widget.ItemTouchHelper
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView


class MainFragment : Fragment() {
    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View {
        return inflater.inflate(R.layout.fragment_main, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        val recyclerView =
            view.findViewById<View>(R.id.recycler_view) as RecyclerView
        recyclerView.setHasFixedSize(true)
        recyclerView.layoutManager = LinearLayoutManager(activity)
        val adapter = RecyclerListAdapter()
        recyclerView.adapter = adapter

        val callback: ItemTouchHelper.Callback = SimpleItemTouchHelperCallback(adapter)
        val touchHelper = ItemTouchHelper(callback)
        touchHelper.attachToRecyclerView(recyclerView)
    }
}

package com.example.dragndropgrid

import android.view.LayoutInflater
import android.view.ViewGroup
import androidx.recyclerview.widget.RecyclerView
import java.util.*


class RecyclerListAdapter : RecyclerView.Adapter<ItemViewHolder>(), ItemTouchHelperAdapter {
    private val mItems: MutableList<String> =
        ArrayList()

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ItemViewHolder {
        val view =
            LayoutInflater.from(parent.context).inflate(R.layout.item_main, parent, false)
        return ItemViewHolder(view)
    }

    override fun onBindViewHolder(holder: ItemViewHolder, position: Int) {
        holder.textView!!.text = mItems[position]
    }

    override fun getItemCount(): Int {
        return mItems.size
    }

    companion object {
        private val STRINGS = arrayOf(
            "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten"
        )
    }

    init {
        mItems.addAll(listOf(*STRINGS))
    }

    override fun onItemMove(fromPosition: Int, toPosition: Int) {
        if (fromPosition < toPosition) {
            for (i in fromPosition until toPosition) {
                Collections.swap(mItems, i, i + 1)
            }
        } else {
            for (i in fromPosition downTo toPosition + 1) {
                Collections.swap(mItems, i, i - 1)
            }
        }
        notifyItemMoved(fromPosition, toPosition)
    }

    override fun onItemDismiss(position: Int) {
        mItems.removeAt(position)
        notifyItemRemoved(position)
    }
}