使用ItemTouchHelper实现RecyclerView Item的滑动删除

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/ShenQiXiaYang/article/details/83829259

本篇文章我们来使用ItemTouchHelper实现RecyclerView Item的滑动删除。
先看一下关于ItemTouchHelper官方文档解释：

This is a utility class to add swipe to dismiss and drag & drop support to RecyclerView.
ItemTouchHelper是一个用于在RecyclerView中实现滑动删除和拖拽的工具类。

在Module中使用RecyclerView，需要修改build.gradle文件，添加依赖。

// RecyclerView
    implementation 'com.android.support:recyclerview-v7:28.0.0'

然后数据类型，People.java

/**
 * 作者    yunyang
 * 时间    2018/11/7 17:39
 * 文件    RecyclerViewDemo
 * 描述   实体类
 */
public class People {

    private String profile;

    public People(String profile) {
        this.profile = profile;
    }

    public String getProfile() {
        return profile;
    }

    public void setProfile(String profile) {
        this.profile = profile;
    }
}

RecyclerView的适配器，DataProfileAdapter.java

import android.content.Context;
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import com.maigu.yang.itemtouchremove.R;
import com.maigu.yang.itemtouchremove.entity.People;

import java.util.List;

/**
 * 作者    yunyang
 * 时间    2018/11/7 17:37
 * 文件    RecyclerViewDemo
 * 描述   适配器
 */
public class DataProfileAdapter extends RecyclerView.Adapter<DataProfileAdapter.MyHolder> {

    private List<People> mList;
    private Context mContext;

    public DataProfileAdapter(Context context, List<People> list) {
        mContext = context;
        mList = list;
    }

    @NonNull
    @Override
    public MyHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        View view = LayoutInflater.from(mContext).inflate(R.layout.item_profile, viewGroup, false);
        return new MyHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull MyHolder myHolder, int i) {
        myHolder.profile.setText(mList.get(i).getProfile());
    }

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

    static class MyHolder extends RecyclerView.ViewHolder {

        TextView profile;

        MyHolder(View view) {
            super(view);
            profile = (TextView) view.findViewById(R.id.item_text_profile);
        }
    }

    public void remove(int position) {
        mList.remove(position);
        notifyItemRemoved(position);
    }

}

Item项的item_profile.xml布局文件。

<?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="50dp"
    android:orientation="horizontal">

    <TextView
        android:id="@+id/item_text_profile"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:ellipsize="end"
        android:gravity="center_vertical"
        android:textColor="@color/colorAccent"
        android:textSize="18sp" />

</LinearLayout>

构建好了实体类People和DataProfileAdapter，在构建DataProfileAdapter时，需要添加一个方法。也就是移除时，刷新RecyclerView适配器（Adapter）的列表。

public void remove(int position) {
        mList.remove(position);
        notifyItemRemoved(position);
    }

在这里为了处理拖动和滑动事件，需要创建ItemTouchHelper.SimpleCallback的实现类。MovieItemTouchHelper.java

import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.helper.ItemTouchHelper;

import com.maigu.yang.itemtouchremove.adapter.DataProfileAdapter;

/**
 * 作者    yunyang
 * 时间    2018/11/7 17:53
 * 文件    RecyclerViewDemo
 * 描述   为了处理拖动和滑动事件，需要创建ItemTouchHelper.SimpleCallback的实现类。
 */
public class MovieItemTouchHelper extends ItemTouchHelper.SimpleCallback {

    private DataProfileAdapter adapter;

    public MovieItemTouchHelper(DataProfileAdapter adapter) {
        super(ItemTouchHelper.UP | ItemTouchHelper.DOWN, ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT);
        this.adapter = adapter;
    }

    /**
     * If you don't support drag & drop, this method will never be called.
     * 如果不支持拖拽，那么这个方法就不会被执行。
     *
     * @param recyclerView The RecyclerView to which ItemTouchHelper is attached to. ItemTouchHelper需要附加到的RecyclerView
     * @param viewHolder   The ViewHolder which is being dragged by the user. 拖动的ViewHolder
     * @param target       The ViewHolder over which the currently active item is being dragged. 目标位置的ViewHolder
     * @return True if the viewHolder has been moved to the adapter position of target. viewHolder是否被移动到目标位置
     */

    @Override
    public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
        return false;
    }

    /**
     * Called when a ViewHolder is swiped by the user.
     * If you don't support swiping, this method will never be called.
     * 如果不支持滑动，方法不会被执行。
     *
     * @param viewHolder The ViewHolder which has been swiped by the user.
     * @param direction  The direction to which the ViewHolder is swiped.
     *                   It is one of UP, DOWN, LEFT or RIGHT.
     *                   If your getMovementFlags(RecyclerView, ViewHolder) method returned relative flags instead of LEFT / RIGHT;
     *                   `direction` will be relative as well. (START or END).
     */

    @Override
    public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
        //Remove item
        adapter.remove(viewHolder.getAdapterPosition());
    }

}

MovieItemTouchHelper默认的构造方法需要传入两个参数。

/**
 * Creates a Callback for the given drag and swipe allowance.
 * @param dragDirs 表示拖拽的方向，有六个类型的值：LEFT、RIGHT、START、END、UP、DOWN
 * @param swipeDirs 表示滑动的方向，有六个类型的值：LEFT、RIGHT、START、END、UP、DOWN
  */
  ItemTouchHelper.SimpleCallback(int dragDirs, int swipeDirs)

MovieItemTouchHelper默认需要实现两个方法onMove(),onSwiped()，

• onMove()是对拖拽的实现
• onSwiped()是对滑动的实现

最后将创建完毕的MovieItemTouchHelper附加到RecyclerView类上即可使用滑动删除功能。
查看MainActivity.java文件。

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.helper.ItemTouchHelper;

import com.maigu.yang.itemtouchremove.adapter.DataProfileAdapter;
import com.maigu.yang.itemtouchremove.entity.People;
import com.maigu.yang.itemtouchremove.utils.MovieItemTouchHelper;

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

public class MainActivity extends AppCompatActivity {

    private RecyclerView mRecyclerView;
    private DataProfileAdapter mAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        initRecy();
    }

    private void initRecy() {
        LinearLayoutManager manager = new LinearLayoutManager(this);
        mAdapter = new DataProfileAdapter(this, Data());
        mRecyclerView.setLayoutManager(manager);
        mRecyclerView.setAdapter(mAdapter);
        ItemTouchHelper.Callback callback = new MovieItemTouchHelper(mAdapter);
        ItemTouchHelper helper = new ItemTouchHelper(callback);
        helper.attachToRecyclerView(mRecyclerView);
    }

    private List<People> Data() {
        List<People> mPeople = new ArrayList<>();
        for (int i = 0; i < 50; i++) {
            mPeople.add(new People("暖暖的云阳 始终唯一，不为所动。   " + i));
        }
        return mPeople;
    }

    private void initView() {
        mRecyclerView = (RecyclerView) findViewById(R.id.recy_index);
    }
}

主要在initRecy方法中，这三方关键代码，调用滑动删除功能。

   ItemTouchHelper.Callback callback = new MovieItemTouchHelper(mAdapter);
   ItemTouchHelper helper = new ItemTouchHelper(callback);
   helper.attachToRecyclerView(mRecyclerView);

接下来看一下MainActivity的布局文件

<?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"
    tools:context=".MainActivity">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recy_index"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

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

</RelativeLayout>

最后是测试结果图演示