本文概述

• ItemTouchHelper类
• Android轻扫以删除RecyclerView项目示例

在本教程中，我们将创建示例以通过使用撤消功能滑动项目来删除RecyclerView的项目。为此，我们将使用Android支持库V7中添加的ItemTouchHelper类。此类用于创建滑动以删除RecyclerView的项目。它具有SimpleCallback类，该类配置了为滑动或移动RecyclerView的项目而执行的事件。
ItemTouchHelper类这是一个实用程序类，它提供了添加滑动以消除和拖动的功能
Android轻扫以删除RecyclerView项目示例使用以下代码创建MainActivity.java类。
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.srcmini.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.srcmini.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.srcmini.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); } }

【android使用undu滑动删除recyclerview上的条目】创建一个布局normal_item.xml，它以正常模式显示。
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，该布局出现在滑动项目期间。
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，该类扩展了ItemTouchHelper.SimpleCallback类，并覆盖其onMove（），onSwiped（）和onChildDraw（）方法。当我们对某个项目执行滑动操作时，将调用onSwiped（）方法，并且onChildDraw（）方法包含在滑动RecyclerView的项目时绘制画布的实现逻辑。
SwipeUtil.java

package example.srcmini.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，并扩展RecyclerView.ViewHolder。
ItemViewHolder.java

package example.srcmini.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，它扩展了RecyclerView.Adapter类并覆盖其onCreateViewHolder（），onBindViewHolder（）方法。
MyAdapter.java

package example.srcmini.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< ItemViewHolder> {private List< String> dataList; private List< String> itemsPendingRemoval; private static final int PENDING_REMOVAL_TIMEOUT = 3000; // 3sec private Handler handler = new Handler(); // hanlder for running delayed runnables HashMap< String, Runnable> pendingRunnables = new HashMap< >(); // map of items to pending runnable, to cancel the removalpublic MyAdapter(List< String> 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 = http://www.srcmini.com/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 = http://www.srcmini.com/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 = http://www.srcmini.com/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类并扩展Fragment类。在此类中，设置适配器MyAdapter.java类和实用程序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.srcmini.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.srcmini.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 = http://www.srcmini.com/{"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< String> getData() { List< String> 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>

colors.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：

文章图片

文章图片

文章图片

推荐阅读

• 

  原神白垩与黑龙急冻树单人怎么刷 急冻树挑战单人打法技巧
• 

  中国农业银行网上银行 错误代码5101 怎么解决,成都市身份证前四位5101的包括哪几个区？
• 

  崩坏3必备圣痕推荐 崩坏3高级区女武神毕业装一览
• 

  前些年琼瑶剧那么火现在怎么没什么人拍了？
• 

  人类历史上首架被击落的隐身战斗机就是美军的F-117战斗机,能否简单介绍一下？
• 

  mysql主从搭建教程 mysql如何实现的主从
• 

  嘴巴里老有一股鱼腥味 口水为什么有味道
• 

  winmount，在windows操作系统中WinMount虚拟磁盘软件附带挂载功能有
• 

  运动鞋气垫坏了怎么办 运动鞋气垫坏了如何处理
• 

  16|16 燕燕丨新的一周，持续精进
• 

  用Photoshop给南宁女孩照片调些古典绿色
• 

  mongodbapi实例 mongodbapi
• 

  芝麻酱和芝麻调味酱有什么区别 芝麻酱和芝麻调味酱有哪些不同
• 

  鸿蒙系统3.0什么时候发布？鸿蒙系统3.0发布时间介绍
• 

  万国醒悟KVK前置流动攻略,KVK前置义务及奖励详解
• 

  你知道哪些中国知名画家？
• 

  什么是烧胎疯狂轰油门 为什么要烧胎
• 

  红酒直接倒入酒杯可以醒酒吗
• 

  甩脂机用完身上痒怎么回事
• 

  描写芬芳的花用多点词语

• android recyclerview列表的例子
• android linkify的例子
• android介绍滑动条示例
• Android从url获取json数据的volley库
• android rss阅读器
• android间隙广告
• android横幅广告
• android谷歌admob
• Android毛玻璃模糊化效果处理