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Android 通过滑动带有撤销功能的项目来删除 RecyclerView 的项目

Android 通过滑动带有撤销功能的项目来删除 RecyclerView 的项目

在本教程中，我们将创建一个示例，通过滑动带有撤销功能的项目来删除 RecyclerView 的项目。为此，我们将使用 ItemTouchHelper 类，该类已添加到Android Support Library V7中。此类用于创建滑动删除RecyclerView项目的功能。它具有 SimpleCallback 类，该类配置在RecyclerView上滑动或移动项目时执行的事件。

ItemTouchHelper类

这是一个实用类，用于为RecyclerView的项目添加滑动删除和拖动功能。根据我们实现的功能，它会重写onMove()或onSwipe()回调方法。

Android滑动删除RecyclerView项目示例

创建一个 MainActivity.java 类，并使用以下代码。

activity_main.xml

ass with the following code.
activity_main.xml
<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="example.javatpoint.com.recyclerviewswipedeleteundo.MainActivity">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/AppTheme.PopupOverlay" />

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

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


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

content_main.xml

<fragment 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:id="@+id/fragment"
    android:name="example.javatpoint.com.recyclerviewswipedeleteundo.MainActivityFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:layout="@layout/fragment_main" />

MainActivity.java

package example.javatpoint.com.recyclerviewswipedeleteundo;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;

public class MainActivity extends AppCompatActivity {

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

    }
}

创建一个布局 regular_item.xml 在正常模式下显示。

regular_item.xml

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

    <TextView
        android:id="@+id/list_item"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Regular Layout"
        android:textSize="28sp" />
</LinearLayout>

创建一个布局 swipe_item.xml 在滑动项期间显示。

swipe_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/swipeLayout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@color/swipebackground"
    android:orientation="horizontal"
    android:padding="@dimen/activity_horizontal_margin"
    android:visibility="visible"
    android:weightSum="3">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="@string/archived_label"
        android:textColor="@android:color/white"
        android:textSize="24sp" />


    <TextView
        android:id="@+id/undo"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="2"
        android:gravity="end"
        android:paddingBottom="5dp"
        android:paddingLeft="16dp"
        android:paddingRight="16dp"
        android:paddingTop="5dp"
        android:text="@string/undo_label"
        android:textColor="@android:color/white"
        android:textSize="22sp"
        android:textStyle="bold" />

</LinearLayout>

customlayout.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">
    <!-- Swipe Layout-->
    <include layout="@layout/swipe_item" />
    <!-- Regular Layout-->
    <include layout="@layout/regular_item" />
</FrameLayout>

创建一个实用程序类 SwipeUtil.java ，它扩展了 ItemTouchHelper.SimpleCallback 类并重写了它的onMove()、onSwiped()和onChildDraw()方法。当我们在一个项目上执行滑动操作时，会调用onSwiped()方法，而onChildDraw()方法包含了在RecyclerView中滑动项目时绘制画布的实现逻辑。

SwipeUtil.java

package example.javatpoint.com.recyclerviewswipedeleteundo;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.support.v4.content.ContextCompat;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.helper.ItemTouchHelper;
import android.view.View;

public abstract class SwipeUtil extends ItemTouchHelper.SimpleCallback {

    private Drawable background;
    private Drawable deleteIcon;
    private int xMarkMargin;
    private boolean initiated;
    private Context context;
    private int leftcolorCode;
    private String leftSwipeLable;

    public SwipeUtil(int dragDirs, int swipeDirs, Context context) {
        super(dragDirs, swipeDirs);
        this.context = context;
    }

    private void init() {
        background = new ColorDrawable();
        xMarkMargin = (int) context.getResources().getDimension(R.dimen.ic_clear_margin);
        deleteIcon = ContextCompat.getDrawable(context, android.R.drawable.ic_menu_delete);
        deleteIcon.setColorFilter(Color.WHITE, PorterDuff.Mode.SRC_ATOP);
        initiated = true;
    }

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

    @Override
    public abstract void onSwiped(RecyclerView.ViewHolder viewHolder, int direction);

    @Override
    public int getSwipeDirs(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {

        return super.getSwipeDirs(recyclerView, viewHolder);
    }

    @Override
    public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder,
                            float dX, float dY, int actionState, boolean isCurrentlyActive) {

        View itemView = viewHolder.itemView;
        if (!initiated) {
            init();
        }

        int itemHeight = itemView.getBottom() - itemView.getTop();
        //Setting Swipe Background
        ((ColorDrawable) background).setColor(getLeftcolorCode());
        background.setBounds(itemView.getRight() + (int) dX, itemView.getTop(), itemView.getRight(), itemView.getBottom());
        background.draw(c);

        int intrinsicWidth = deleteIcon.getIntrinsicWidth();
        int intrinsicHeight = deleteIcon.getIntrinsicWidth();

        int xMarkLeft = itemView.getRight() - xMarkMargin - intrinsicWidth;
        int xMarkRight = itemView.getRight() - xMarkMargin;
        int xMarkTop = itemView.getTop() + (itemHeight - intrinsicHeight) / 2;
        int xMarkBottom = xMarkTop + intrinsicHeight;

        //Setting Swipe Icon
        deleteIcon.setBounds(xMarkLeft, xMarkTop + 16, xMarkRight, xMarkBottom);
        deleteIcon.draw(c);

        //Setting Swipe Text
        Paint paint = new Paint();
        paint.setColor(Color.WHITE);
        paint.setTextSize(48);
        paint.setTextAlign(Paint.Align.CENTER);
        c.drawText(getLeftSwipeLable(), xMarkLeft + 40, xMarkTop + 10, paint);

        super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
    }

    public String getLeftSwipeLable() {
        return leftSwipeLable;
    }

    public void setLeftSwipeLable(String leftSwipeLable) {
        this.leftSwipeLable = leftSwipeLable;
    }

    public int getLeftcolorCode() {
        return leftcolorCode;
    }

    public void setLeftcolorCode(int leftcolorCode) {
        this.leftcolorCode = leftcolorCode;
    }
}

创建一个 ItemViewHolder.java 类并继承RecyclerView.ViewHolder。

ItemViewHolder.java

package example.javatpoint.com.recyclerviewswipedeleteundo;

import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.TextView;

public class ItemViewHolder extends RecyclerView.ViewHolder {

    public LinearLayout regularLayout;
    public LinearLayout swipeLayout;
    public TextView listItem;
    public TextView undo;

    public ItemViewHolder(View view) {
        super(view);

        regularLayout = view.findViewById(R.id.regularLayout);
        listItem =  view.findViewById(R.id.list_item);
        swipeLayout = view.findViewById(R.id.swipeLayout);
        undo =  view.findViewById(R.id.undo);
    }
}

创建一个适配器类 MyAdapter.java ，该类继承RecyclerView.Adapter 类，并重写其onCreateViewHolder()和onBindViewHolder()方法。

MyAdapter.java

package example.javatpoint.com.recyclerviewswipedeleteundo;

import android.os.Handler;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

public class MyAdapter extends RecyclerView.Adapter {

    private List dataList;
    private List itemsPendingRemoval;

    private static final int PENDING_REMOVAL_TIMEOUT = 3000; // 3sec
    private Handler handler = new Handler(); // hanlder for running delayed runnables
    HashMap pendingRunnables = new HashMap<>(); // map of items to pending runnable, to cancel the removal


    public MyAdapter(List dataList) {
        this.dataList = dataList;
        itemsPendingRemoval = new ArrayList<>();
    }

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

    @Override
    public void onBindViewHolder(ItemViewHolder itemViewHolder, int position) {

        final String data = dataList.get(position);

        if (itemsPendingRemoval.contains(data)) {
            /** show swipe layout and hide regular layout */
            itemViewHolder.regularLayout.setVisibility(View.GONE);
            itemViewHolder.swipeLayout.setVisibility(View.VISIBLE);
            itemViewHolder.undo.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    undoOpt(data);
                }
            });
        } else {
            /** show regular layout and hide swipe layout*/
            itemViewHolder.regularLayout.setVisibility(View.VISIBLE);
            itemViewHolder.swipeLayout.setVisibility(View.GONE);
            itemViewHolder.listItem.setText(data);
        }
    }

    private void undoOpt(String customer) {
        Runnable pendingRemovalRunnable = pendingRunnables.get(customer);
        pendingRunnables.remove(customer);
        if (pendingRemovalRunnable != null)
            handler.removeCallbacks(pendingRemovalRunnable);
        itemsPendingRemoval.remove(customer);
        // this will rebind the row in "normal" state
        notifyItemChanged(dataList.indexOf(customer));
    }

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

    public void pendingRemoval(int position) {

        final String data = dataList.get(position);
        if (!itemsPendingRemoval.contains(data)) {
            itemsPendingRemoval.add(data);
            // this will redraw row in "undo" state
            notifyItemChanged(position);
            //create, store and post a runnable to remove the data
            Runnable pendingRemovalRunnable = new Runnable() {
                @Override
                public void run() {
                    remove(dataList.indexOf(data));
                }
            };
            handler.postDelayed(pendingRemovalRunnable, PENDING_REMOVAL_TIMEOUT);
            pendingRunnables.put(data, pendingRemovalRunnable);
        }
    }

    public void remove(int position) {
        String data = dataList.get(position);
        if (itemsPendingRemoval.contains(data)) {
            itemsPendingRemoval.remove(data);
        }
        if (dataList.contains(data)) {
            dataList.remove(position);
            notifyItemRemoved(position);
        }
    }

    public boolean isPendingRemoval(int position) {
        String data = dataList.get(position);
        return itemsPendingRemoval.contains(data);
    }
}

创建一个 MainActivityFragment.java 类并继承Fragment类。在这个类中，设置适配器MyAdapter.java类和工具类SwipeUtil.java类。

fragment_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="example.javatpoint.com.recyclerviewswipedeleteundo.MainActivityFragment"
    tools:showIn="@layout/activity_main">

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

MainActivityFragment.java

package example.javatpoint.com.recyclerviewswipedeleteundo;

import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.support.v4.content.ContextCompat;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.helper.ItemTouchHelper;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import java.util.ArrayList;
import java.util.List;

public class MainActivityFragment extends Fragment {

    private RecyclerView mRecyclerView;
    private MyAdapter myAdapter;
    String[] listValue = {"C Tutorial","C++ Tutorial","Data Structure","Java Tutorial","Android Example","Kotlin Programing","Python language","Ruby Tutorial",".Net Tutorial","MySQL Database"};
    public MainActivityFragment() {
    }

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

    @Override
    public void onResume() {
        super.onResume();
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity());
        linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        mRecyclerView.setLayoutManager(linearLayoutManager);
        myAdapter = new MyAdapter(getData());
        mRecyclerView.setAdapter(myAdapter);

        setSwipeForRecyclerView();
    }

    private List getData() {
        List modelList = new ArrayList<>();
        for (int i = 0; i < listValue.length; i++) {
            modelList.add(listValue[i]);
        }
        return modelList;
    }

    private void setSwipeForRecyclerView() {

        SwipeUtil swipeHelper = new SwipeUtil(0, ItemTouchHelper.LEFT, getActivity()) {
            @Override
            public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
                int swipedPosition = viewHolder.getAdapterPosition();
                myAdapter = (MyAdapter)mRecyclerView.getAdapter();
                myAdapter.pendingRemoval(swipedPosition);
            }

            @Override
            public int getSwipeDirs(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
                int position = viewHolder.getAdapterPosition();
                myAdapter = (MyAdapter) mRecyclerView.getAdapter();
               if (myAdapter.isPendingRemoval(position)) {
                     return 0;
                }
                return super.getSwipeDirs(recyclerView, viewHolder);
            }
        };

        ItemTouchHelper mItemTouchHelper = new ItemTouchHelper(swipeHelper);
        mItemTouchHelper.attachToRecyclerView(mRecyclerView);
        //set swipe label
        swipeHelper.setLeftSwipeLable("Archive");
        //set swipe background-Color
        swipeHelper.setLeftcolorCode(ContextCompat.getColor(getActivity(), R.color.swipebackground));
    }
}

strings.xml

<resources>
    <string name="app_name">RecyclerView SwipeDeleteUndo</string>
    <string name="action_settings">Settings</string>
    <string name="hello_blank_fragment">Hello blank fragment</string>
    <string name="undo_label"><u>Undo</u></string>
    <string name="archived_label">Archive</string>
</resources>

dimens.xml

<resources>
    <dimen name="fab_margin">16dp</dimen>
    <dimen name="activity_horizontal_margin">16dp</dimen>
    <dimen name="activity_vertical_margin">16dp</dimen>
    <dimen name="ic_clear_margin">56dp</dimen>
    <dimen name="text_size_medium">20sp</dimen>
</resources>

color.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="colorPrimary">#3F51B5</color>
    <color name="colorPrimaryDark">#303F9F</color>
    <color name="colorAccent">#FF4081</color>
    <color name="swipebackground">#cf0b4e</color>
</resources>

输出：

Android 通过滑动带有撤销功能的项目来删除 RecyclerView 的项目

Camera课程

Camera API2 教程

API2 教程
Camera 性能教程

Perf 教程
Camera Native Framework 教程

Native FW 教程
Camera QCOM ISP 教程

ISP 教程
Camera QCOM Sensor 教程

Sensor 教程

Python教程

Python 教程

Python 教程
NumPy 教程

NumPy 教程
Django 教程

Django 教程

Java教程

Java 教程

Java 教程

Web教程

JavaScript 教程

JavaScript 教程
jQuery 教程

jQuery 教程
CSS 教程

CSS 教程
PHP 教程

PHP 教程
Laravel 教程

Laravel 教程
TypeScript 教程

TypeScript 教程
WordPress 教程

WordPress 教程

数据库教程

SQL 教程

SQL 教程
SQLite 教程

SQLite 教程
MySQL 教程

MySQL 教程
PL/SQL 教程

PL/SQL 教程
MongoDB 教程

MongoDB 教程

图形图像教程

OpenCV 教程

OpenCV 教程

办公软件教程

Excel 教程

Excel 教程

Linux教程

Linux命令全集

Linux命令全集
Linux内核API

Linux内核API
LVGL 教程

LVGL 教程

计算机教程

操作系统 教程

操作系统 教程
计算机网络 教程

计算机网络 教程
C语言 教程

C语言 教程
C++ 教程

C++ 教程
Swift 教程

Swift 教程

大数据教程

Hadoop 教程

Hadoop 教程
Spark 教程

Spark 教程
Scala 教程

Scala 教程

开发工具教程

Git 教程

Git 教程
Jenkins 教程

Jenkins 教程
ChatGPT 教程

ChatGPT 教程
IntelliJ 教程

IntelliJ 教程

Android 精选笔记