PullToRefresh上拉加载和下拉刷新

1—添加依赖

implementation ‘com.github.userswlwork:pull-to-refresh:1.0.0’
implementation ‘com.google.code.gson:gson:2.8.5’

2— 添加权限

3—添加布局

<com.handmark.pulltorefresh.library.PullToRefreshListView
android:id="@+id/plv"
android:layout_width=“match_parent”
android:layout_height=“match_parent”
/>

4.MainActivity

public class MainActivity extends AppCompatActivity {
String urlString = “http://api.expoon.com/AppNews/getNewsList/type/1/p/1”;
private PullToRefreshListView plv;
ArrayList list=new ArrayList<>();
private ArrayAdapter madapter;
int page=0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
plv = findViewById(R.id.plv);
//上下拉都支持
plv.setMode(PullToRefreshBase.Mode.BOTH);
madapter = new ArrayAdapter<>(MainActivity.this,android.R.layout.simple_list_item_1,list);

    plv.setAdapter(madapter);
    //请求网络
    getNetData(0);
    //处理上拉和下拉的操作;
    plv.setOnRefreshListener(new PullToRefreshBase.OnRefreshListener2<ListView>() {
        @Override
        public void onPullDownToRefresh(PullToRefreshBase<ListView> pullToRefreshBase) {
            list.clear();
            getNetData(0);
        }

        @Override
        public void onPullUpToRefresh(PullToRefreshBase<ListView> pullToRefreshBase) {
            page++;
            getNetData(page);
        }
    });
}

private void getNetData(int page) {
    String murl=urlString+page;
    new MAsyncTask().execute(murl);
}

private class MAsyncTask extends AsyncTask<String,Void,String>{


    @Override
    protected String doInBackground(String... strings) {
        return NetWordUtils.getNetjson(strings[0]);
    }

    @Override
    protected void onPostExecute(String s) {
        super.onPostExecute(s);
        Gson gson = new Gson();
        Product product = gson.fromJson(s, Product.class);
        List<Product.DataBean> data = product.getData();

        ArrayList<String> strlist=new ArrayList<String>();
        for (int i = 0; i < data.size(); i++) {
            strlist.add(data.get(i).getNews_title());
        }
        list.addAll(strlist);
        madapter.notifyDataSetChanged();
        plv.onRefreshComplete();//让刷新头和刷新底部返回

    }
}

}