本文主要是介绍RecycleView结合ItemTouchHelper实现拖动排序，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
最近项目中需要实现对某一类条目进行拖动排序功能，实现技术方案就是利用ItemTouchHelper绑定RecyclerView、ItemTouchHelper.Callback来实现UI更新，并且实现动态控制是否开启拖动功能。其中，ItemTouchHelper是Google在androidx包中添加的，其于RecyclerView配合可以比较容易地实现这个功能。
1、布局文件
a、activity的布局文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:orientation="vertical"android:layout_width="match_parent"android:layout_height="match_parent"android:background="@color/cf5f5f5"><include layout="@layout/title_layout"/><Viewandroid:layout_width="match_parent"android:layout_height="1dp"android:background="@color/ce5e5e5"/><RelativeLayoutandroid:layout_width="match_parent"android:layout_height="50dp"android:background="@color/white"><TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="@string/custom_order"android:textColor="@color/c333333"android:textSize="14sp"android:layout_centerVertical="true"android:layout_marginLeft="12dp"/><ToggleButtonandroid:id="@+id/toggleBtn"android:layout_width="48dp"android:layout_height="28dp"android:layout_centerVertical="true"android:layout_marginRight="12dp"android:background="@drawable/toggle_drawable_selector"android:button="@null"android:textOff=""android:textOn=""android:layout_alignParentRight="true"/></RelativeLayout><RelativeLayoutandroid:id="@+id/tipLayout"android:layout_width="match_parent"android:layout_height="50dp"android:layout_marginTop="20dp"><TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="@string/custom_order_tip1"android:textColor="@color/c808080"android:textSize="12sp"android:layout_centerVertical="true"android:layout_marginLeft="12dp"/><TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text="@string/custom_order_tip2"android:textColor="@color/c808080"android:textSize="12sp"android:layout_centerVertical="true"android:layout_marginRight="12dp"android:layout_alignParentRight="true"/></RelativeLayout><androidx.recyclerview.widget.RecyclerViewandroid:id="@+id/recycleView"android:layout_width="match_parent"android:layout_height="wrap_content"/>
</LinearLayout>
b、RecycleView的listitem布局文件
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="match_parent"android:layout_height="50dp"><ImageViewandroid:id="@+id/image"android:layout_width="24dp"android:layout_height="24dp"android:layout_alignParentLeft="true"android:layout_centerVertical="true"android:layout_marginLeft="12dp"android:src="@mipmap/icon_bank_others"/><TextViewandroid:id="@+id/cardTypeTxt"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="xx借记卡"android:textColor="@color/c333333"android:textSize="14sp"android:layout_centerVertical="true"android:layout_marginLeft="12dp"android:layout_toRightOf="@id/image"/><TextViewandroid:id="@+id/cardNoTxt"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="(8800)"android:textColor="@color/c808080"android:textSize="14sp"android:layout_centerVertical="true"android:layout_marginLeft="6dp"android:layout_toRightOf="@id/cardTypeTxt"/><ImageViewandroid:id="@+id/selectImage"android:layout_width="50dp"android:layout_height="50dp"android:scaleType="center"android:layout_alignParentRight="true"android:layout_centerVertical="true"android:src="@mipmap/sort_line"/>
</RelativeLayout>2、实现ItemTouchHelper.Callback
private ItemTouchHelper.Callback callback =
new ItemTouchHelper.Callback() {public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {//首先回调的方法,返回int表示是否监听该方向int dragFlag = ItemTouchHelper.DOWN | ItemTouchHelper.UP;//拖拽int swipeFlag = 0;//侧滑删除return makeMovementFlags(dragFlag, swipeFlag);}@Overridepublic void onSwiped(@NonNull RecyclerView.ViewHolder viewHolder, int direction) {}public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {if (mAdapter != null) {mAdapter.onMove(viewHolder.getAdapterPosition(), target.getAdapterPosition());}return true;}public void onSelectedChanged(ViewHolder viewHolder, int actionState) {if (actionState != 0) {viewHolder.itemView.setAlpha(0.9f);}super.onSelectedChanged(viewHolder, actionState);}public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {super.clearView(recyclerView, viewHolder);viewHolder.itemView.setAlpha(1.0f);if (mAdapter != null) {mAdapter.notifyDataSetChanged();mSortedList = mAdapter.getSortedDataList();LogUtils.debug(TAG, "callback clearView: " + JSONObject.toJSONString(mSortedList));refreshCardSort(mSortedList);}}};3、初始化RecycleView，并绑定ItemTouchHelper
mAdapter = new MyAdapter(mSortedList);recyclerView.setAdapter(mAdapter);LinearLayoutManager llm = new LinearLayoutManager(mContext, LinearLayoutManager.VERTICAL, false);recyclerView.setLayoutManager(llm);//这两句是关键，完成RecycleView和ItemTouchHelper的绑定ItemTouchHelper helper = new ItemTouchHelper(callback);helper.attachToRecyclerView(recyclerView);
4、定义自己的Adapter
private class MyAdapter extends RecyclerView.Adapter<ViewHolder> {private List<AccountInfo> mDataList;public MyAdapter (List<AccountInfo> dataList) {this.mDataList = dataList;}public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {return new ViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.card_order_listitem, parent, false));}public void onBindViewHolder(ViewHolder holder, final int position) {final AccountInfo item = mDataList.get(position);if (item != null) {holder.tvContentType.setText(getCardNoType(item.getAccountType()));holder.tvContentNo.setText(getCardNo(item.getAccountNo()));}}public int getItemCount() {return mDataList.size();}public void onMove(int fromPosition, int toPosition) {//对原数据进行移动Collections.swap(mDataList, fromPosition, toPosition);//通知数据移动notifyItemMoved(fromPosition, toPosition);LogUtils.debug(TAG, "MyAdapter onMove fromPosition: " + fromPosition + ", toPosition: " + toPosition);}public List<AccountInfo> getSortedDataList() {return this.mDataList;}}public class ViewHolder extends RecyclerView.ViewHolder {public TextView tvContentType;public TextView tvContentNo;public ViewHolder(View view) {super(view);this.tvContentType = (TextView)view.findViewById(R.id.cardTypeTxt);this.tvContentNo = (TextView)view.findViewById(R.id.cardNoTxt);}}其他参数定义：private List<AccountInfo> mSortedList;private MyAdapter mAdapter;bean定义如下：
package com.qdone.qrcode.pay.qrcodesdkdemo.model;/*** Time: 2024/1/26* Author:* Description:*/
public class AccountInfo {private String accountId;private String custId;private String accountNo;private String accountType;private String bankName;private String displayOrder;/*** 是否是默认账户，0-普通账户 1-默认账户*/private String defaultFlag;@Overridepublic String toString() {return "AccountInfo{" +"accountId='" + accountId + '\'' +", custId='" + custId + '\'' +", accountNo='" + accountNo + '\'' +", accountType='" + accountType + '\'' +", bankName='" + bankName + '\'' +", displayOrder='" + displayOrder + '\'' +", defaultFlag='" + defaultFlag + '\'' +'}';}public String getAccountId() {return accountId;}public void setAccountId(String accountId) {this.accountId = accountId;}public String getCustId() {return custId;}public void setCustId(String custId) {this.custId = custId;}public String getAccountNo() {return accountNo;}public void setAccountNo(String accountNo) {this.accountNo = accountNo;}public String getAccountType() {return accountType;}public void setAccountType(String accountType) {this.accountType = accountType;}public String getBankName() {return bankName;}public void setBankName(String bankName) {this.bankName = bankName;}public String getDisplayOrder() {return displayOrder;}public void setDisplayOrder(String displayOrder) {this.displayOrder = displayOrder;}public String getDefaultFlag() {return defaultFlag;}public void setDefaultFlag(String defaultFlag) {this.defaultFlag = defaultFlag;}
}
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