思路
1、列表页面（MainActivity）为登录成功的跳转页面
2、使用httpclient发送分页查询的异步请求
3、开发分页查询的接口，对app客户端发送的请求进行处理
4、使用SwipeRefreshLayout组件
5、SwipeRefreshLayout组件只接受一个子组件：即需要刷新的那个组件。使用一个侦听机制来通知拥有该组件的监听器有刷新事件发生，换句话说我们的Activity必须实现通知的接口。该Activity负责处理事件刷新和刷新相应的视图。一旦监听者接收到该事件，就决定了刷新过程中应处理的地方。
6、如果要展示一个“刷新动画”，它必须调用setRefrshing（true），否则取消动画就调用setRefreshing（false）。
image.png
参考资料：
下拉刷新、分页，AsyncTask
android官方下拉刷新控件SwipeRefreshLayout的使用
列表页面设计
Java代码如下：
package com.yangzc.myerp;
import android.os.Handler;
import android.os.Message;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AbsListView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.TextHttpResponseHandler;
import java.util.ArrayList;
import java.util.List;
import cz.msebera.android.httpclient.Header;
public class MainActivity extends AppCompatActivity implements AbsListView.OnScrollListener {
private SwipeRefreshLayout swipeRefreshLayout;
private ListView lv;
private ArrayAdapter adapter;
private List<String> list;
private View footerView;
private AsyncHttpClient ahc;
private int page=1;
private int visibleLastIndex;//用来可显示的最后一条数据的索引
private Handler handler = new Handler(){
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
switch (msg.what){
case 0x101:
if (swipeRefreshLayout.isRefreshing()){
adapter.notifyDataSetChanged();
swipeRefreshLayout.setRefreshing(false);//设置不刷新
}
break;
}
}
};
class MyTextHttpResponseHandler extends TextHttpResponseHandler{
@Override
public void onFailure(int statusCode, Header[] headers, String responseBody, Throwable error) {
//super.onFailure(statusCode, headers, responseBody, error);
}
@Override
public void onSuccess(int statusCode, Header[] headers, String responseBody) {
System.out.println("服务器返回的内容为："+responseBody);
//JSONObject obj = (JSONObject)JSON.parse(responseBody);
JSONArray arr = JSON.parseArray(responseBody);
for(Object o:arr){
JSONObject emp = (JSONObject)o;
JSONObject dept = (JSONObject)emp.get("dept");
list.add(dept.getString("city")+"-"+dept.getString("dName")+"-"+emp.getString("name"));
}
handler.sendEmptyMessage(0x101);//通过handler发送一个更新数据的标记
//吐司Android studio与web后台数据交互获得的值
Toast.makeText(MainActivity.this, "刷新了"+arr.size()+"条数据", Toast.LENGTH_SHORT).show();
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
swipeRefreshLayout = findViewById(R.id.main_srl);
lv = findViewById(R.id.main_lv);
footerView = getLayoutInflater().inflate(R.layout.loading_layout,null);
lv.addFooterView(footerView);
lv.setOnScrollListener(this);
list = new ArrayList<>();
String path="http://192.168.1.14:8080/myerp/list.action?page="+page;
//创建客户端工具
ahc=new AsyncHttpClient();
adapter = new ArrayAdapter(this,R.layout.simple_list,
android.R.id.text1,list);
lv.setAdapter(adapter);
//发送请求
ahc.get(path,new MyTextHttpResponseHandler());
swipeRefreshLayout.setColorSchemeResources(android.R.color.holo_blue_bright, android.R.color.holo_green_light,
android.R.color.holo_orange_light, android.R.color.holo_red_light);
swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
page++;
String path="http://192.168.1.14:8080/myerp/list.action?page="+page;
//设值提交方式
ahc.get(path,new MyTextHttpResponseHandler());
handler.sendEmptyMessage(0x101);//通过handler发送一个更新数据的标记
}
});
lv.removeFooterView(footerView);
}
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
if(adapter.getCount() == visibleLastIndex && scrollState == SCROLL_STATE_IDLE){
//new LoadDataThread().start();
}
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
visibleLastIndex = firstVisibleItem + visibleItemCount - 1;//减去最后一个加载中那条
}
}
activity_main.xml配置如下：
<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"
tools:context=".MainActivity" >
<android.support.v4.widget.SwipeRefreshLayout
android:id="@+id/main_srl"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<ListView
android:id="@+id/main_lv"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</ListView>
</android.support.v4.widget.SwipeRefreshLayout>
</RelativeLayout>
loading_layout.xml配置如下：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<ProgressBar
style="?android:attr/progressBarStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/progressBar"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="正在玩命加载中...."
android:id="@+id/textView2"/>
</RelativeLayout>
simple_list.xml配置如下：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@android:id/text1"
android:textColor="#00F"
android:textSize="30sp"/>
</RelativeLayout>
开发分页查询的接口
后台代码如下：
package com.myerp.handler;
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import com.alibaba.fastjson.JSON;
import com.myerp.dao.EmployeeDAO;
import com.myerp.dao.UserDAO;
import com.myerp.model.Employee;
import com.myerp.model.MyPage;
public class ActionServlet2 extends HttpServlet {
public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setCharacterEncoding("UTF-8");
//1.获取URI
String uri = request.getRequestURI();
HttpSession session = request.getSession();
//2.截取URI中的动作
uri = uri.substring(uri.lastIndexOf("/"),uri.lastIndexOf("."));
if(uri.equals("/login")){
//判断用户名和密码
String uname = request.getParameter("name");
String pwd = request.getParameter("pwd");
UserDAO udao = new UserDAO();
try{
//登录认证
if(udao.auth(uname,pwd)==false){
//登录失败
//request.setAttribute("msg","用户名或密码不正确");
response.getWriter().print("{\"result\":\"fail\",\"message\":\"用户或密码错误\"}");
}else{
//登录成功,记录用户信息到session中
session.setAttribute("uname",uname);
//session过期时间设置为5分钟
session.setMaxInactiveInterval(300);
response.getWriter().print("{\"result\":\"success\",\"message\":\"登录成功\"}");
}
}catch(Exception e){
e.printStackTrace();
}
}else if(uri.equals("/list")) {
int pageNum = 1;
MyPage<Employee> page = null;
List<Employee> emps = null;
if(request.getParameter("page")!=null){
pageNum = Integer.parseInt(request.getParameter("page"));
}
//创建dao对象
EmployeeDAO dao = new EmployeeDAO();
//调用findAll()方法获取数据
try {
page = dao.findAllByPage(pageNum,15);
emps = page.getList();
System.out.println(JSON.toJSONString(emps));
response.getWriter().print(JSON.toJSONString(emps));
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
测试
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