实现下拉刷新和上拉加载的完整代码如下：
一、布局文件代码如下：
主界面main.xml代码:
<?xml version="1.0" encoding="utf-8"?> <LinearLayout 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"> <androidx.swiperefreshlayout.widget.SwipeRefreshLayout android:id="@+id/refreshLayout" android:layout_width="match_parent" android:layout_height="match_parent"> <androidx.recyclerview.widget.RecyclerView android:id="@+id/recyclerView" android:layout_width="match_parent" android:layout_height="match_parent" /> </androidx.swiperefreshlayout.widget.SwipeRefreshLayout> </LinearLayout>
item的列表布局：
<?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="match_parent" android:orientation="vertical" > <TextView android:id="@+id/tv" android:layout_width="match_parent" android:layout_height="50dp" android:background="@android:color/holo_blue_dark" android:gravity="center" android:textSize="30sp" android:textColor="#ffffff" android:text="11" android:layout_marginBottom="1dp"/> </LinearLayout>
底部footView的布局代码如下：
<?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="match_parent" android:orientation="vertical" > <TextView android:id="@+id/tips" android:layout_width="match_parent" android:layout_height="wrap_content" android:gravity="center" android:padding="10dp" android:textSize="15sp" android:layout_marginBottom="1dp"/> </LinearLayout>
二、后台代码逻辑代码如下：
适配器MyAdapter代码如下：
具体的详解已经在注释中写出
package com.example.swiperefreshdemo; import android.content.Context; import android.os.Handler; import android.os.Looper; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.ProgressBar; import android.widget.TextView; import androidx.annotation.NonNull; import androidx.recyclerview.widget.RecyclerView; import java.util.ArrayList; import java.util.List; public class MyAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> { private List<String> datas; private Context context; private int normalType = 0; private int footType = 1; private boolean hasMore = true; private boolean fadeTips = false; private Handler mHandler = new Handler(Looper.getMainLooper()); public MyAdapter(List<String> datas, Context context, boolean hasMore) { this.datas = datas; this.context = context; this.hasMore = hasMore; } @Override public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { if (viewType == normalType) { return new NormalHolder(LayoutInflater.from(context).inflate(R.layout.item, null)); } else { return new FootHolder(LayoutInflater.from(context).inflate(R.layout.footview, null)); } } @Override public void onBindViewHolder(final RecyclerView.ViewHolder holder, int position) { if (holder instanceof NormalHolder) { ((NormalHolder) holder).textView.setText(datas.get(position)); } else { ((FootHolder) holder).tips.setVisibility(View.VISIBLE); if (hasMore == true) { fadeTips = false; if (datas.size() > 0) { ((FootHolder) holder).tips.setText("正在加载更多..."); } } else { if (datas.size() > 0) { ((FootHolder) holder).tips.setText("没有更多数据了"); mHandler.postDelayed(new Runnable() { @Override public void run() { ((FootHolder) holder).tips.setVisibility(View.GONE); fadeTips = true; hasMore = true; } }, 500); } } } } @Override public int getItemCount() { return datas.size() + 1; } public int getRealLastPosition() { return datas.size(); } public void updateList(List<String> newDatas, boolean hasMore) { if (newDatas != null) { datas.addAll(newDatas); } this.hasMore = hasMore; notifyDataSetChanged(); } class NormalHolder extends RecyclerView.ViewHolder { private TextView textView; public NormalHolder(View itemView) { super(itemView); textView = (TextView) itemView.findViewById(R.id.tv); } } class FootHolder extends RecyclerView.ViewHolder { private TextView tips; public FootHolder(View itemView) { super(itemView); tips = (TextView) itemView.findViewById(R.id.tips); } } public boolean isFadeTips() { return fadeTips; } public void resetDatas() { datas = new ArrayList<>(); } @Override public int getItemViewType(int position) { if (position == getItemCount() - 1) { return footType; } else { return normalType; } } }
MainActivity代码如下：
package com.example.swiperefreshdemo; import androidx.appcompat.app.AppCompatActivity; import androidx.recyclerview.widget.DefaultItemAnimator; import androidx.recyclerview.widget.GridLayoutManager; import androidx.recyclerview.widget.RecyclerView; import androidx.swiperefreshlayout.widget.SwipeRefreshLayout; import android.os.Bundle; import android.os.Handler; import android.os.Looper; import java.util.ArrayList; import java.util.List; public class MainActivity extends AppCompatActivity implements SwipeRefreshLayout.OnRefreshListener { //声明一个下拉刷新的对象 private SwipeRefreshLayout refreshLayout; private RecyclerView recyclerView; private List<String> list; private int lastVisibleItem = 0; private final int PAGE_COUNT = 30; //声明一个网格布局管理器 private GridLayoutManager mLayoutManager; private MyAdapter adapter; private Handler mHandler = new Handler(Looper.getMainLooper()); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initData(); findView(); initRefreshLayout(); initRecyclerView(); } private void initData() { list = new ArrayList<>(); for (int i = 1; i <= 60; i++) { list.add("条目" + i); } } private void findView() { //从布局文件中获取名叫refreshLayout的下拉刷新布局 refreshLayout = (SwipeRefreshLayout) findViewById(R.id.refreshLayout); recyclerView = (RecyclerView) findViewById(R.id.recyclerView); } private void initRefreshLayout() { //设置下拉刷新布局的进度圆圈颜色 refreshLayout.setColorSchemeResources(android.R.color.holo_blue_light, android.R.color.holo_red_light, android.R.color.holo_orange_light, android.R.color.holo_green_light); //给refreshLayout设置下拉刷新监听器 refreshLayout.setOnRefreshListener(this); } private void initRecyclerView() { adapter = new MyAdapter(getDatas(0, PAGE_COUNT), this, getDatas(0, PAGE_COUNT).size() > 0 ? true : false); //网格布局管理器,参数设置为1,表示该数据独占一行 mLayoutManager = new GridLayoutManager(this, 1); recyclerView.setLayoutManager(mLayoutManager); recyclerView.setAdapter(adapter); recyclerView.setItemAnimator(new DefaultItemAnimator()); recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() { @Override public void onScrollStateChanged(RecyclerView recyclerView, int newState) { super.onScrollStateChanged(recyclerView, newState); if (newState == RecyclerView.SCROLL_STATE_IDLE) { //判断是否滑动到底部 if (adapter.isFadeTips() == false && lastVisibleItem + 1 == adapter.getItemCount()) { mHandler.postDelayed(new Runnable() { @Override public void run() { //加载更多数据,一次加载40个数据 updateRecyclerView(adapter.getRealLastPosition(), adapter.getRealLastPosition() + PAGE_COUNT); } }, 500); } if (adapter.isFadeTips() == true && lastVisibleItem + 2 == adapter.getItemCount()) { mHandler.postDelayed(new Runnable() { @Override public void run() { updateRecyclerView(adapter.getRealLastPosition(), adapter.getRealLastPosition() + PAGE_COUNT); } }, 500); } } } @Override public void onScrolled(RecyclerView recyclerView, int dx, int dy) { super.onScrolled(recyclerView, dx, dy); //findLastVisibleItemPosition显示界面的最后一个位置 lastVisibleItem = mLayoutManager.findLastVisibleItemPosition(); } }); } private List<String> getDatas(final int firstIndex, final int lastIndex) { List<String> resList = new ArrayList<>(); for (int i = firstIndex; i < lastIndex; i++) { if (i < list.size()) { resList.add(list.get(i)); } } return resList; } private void updateRecyclerView(int fromIndex, int toIndex) { List<String> newDatas = getDatas(fromIndex, toIndex); if (newDatas.size() > 0) { adapter.updateList(newDatas, true); } else { adapter.updateList(null, false); } } @Override public void onRefresh() { refreshLayout.setRefreshing(true); adapter.resetDatas(); updateRecyclerView(0, PAGE_COUNT); mHandler.postDelayed(new Runnable() { @Override public void run() { refreshLayout.setRefreshing(false); } }, 1000); } }
以上就是实现下拉刷新和上拉加载的完整代码，这是加载的本地数据，如果在项目中运用的话，把本地获取数据，替换为网络获取即可。
效果图如下：
这个功能就到此结束了，写的很简陋，有不当之处，可在评论区指正，一起学习，共同进步！
