android ListView 分页加载数据

时间：2021-10-31 16:28:46

1.mainActivity

<LinearLayout 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:paddingLeft="@dimen/activity_horizontal_margin"

    android:orientation="vertical"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    android:paddingBottom="@dimen/activity_vertical_margin" tools:context="mydemo.mycom.demo2.Home">

    <LinearLayout

        android:orientation="horizontal"

        android:layout_width="fill_parent"

        android:layout_height="wrap_content">

        <Button

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:id="@+id/btn_home_to_login"

            android:text="@string/btn_to_register"/>

        <Button

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:id="@+id/btn_exit"

            android:text="@string/btn_to_exit"/>

        </LinearLayout>

   <ListView

       android:id="@+id/lv"

       android:layout_width="fill_parent"

       android:layout_height="match_parent"></ListView>

</LinearLayout>

2.ListView的itemActivity

<LinearLayout 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:paddingLeft="@dimen/activity_horizontal_margin"

    android:orientation="horizontal"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    android:paddingBottom="@dimen/activity_vertical_margin" tools:context="mydemo.mycom.demo2.Home">

        <TextView

            android:id="@+id/tv_id"

            android:layout_width="wrap_content"

            android:textColor="#FF172366"

            android:padding="5dp"

            android:layout_height="wrap_content" />

        <TextView

            android:id="@+id/tv_username"

            android:layout_width="wrap_content"

            android:padding="5dp"

            android:textColor="#FF870918"

            android:layout_height="wrap_content" />

        <TextView

            android:id="@+id/tv_password"

            android:layout_width="wrap_content"

            android:padding="5dp"

            android:layout_height="wrap_content" />

</LinearLayout>

3.ListView footerActivity

<LinearLayout 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:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    android:paddingBottom="@dimen/activity_vertical_margin"

    tools:context="mydemo.mycom.demo2.Footer">

    <ProgressBar

        android:layout_width="50dp"

        android:layout_height="wrap_content"

        style="?android:attr/progressBarStyle"

        />

    <TextView android:text="@string/load_text"

        android:textSize="20sp"

        android:gravity="center_vertical"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content" />

</LinearLayout>

4.MainActivity.java

package mydemo.mycom.demo2;

import android.content.Intent;

import android.os.Handler;

import android.os.Message;

import android.support.v7.app.ActionBarActivity;

import android.os.Bundle;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.view.ViewGroup;

import android.widget.AbsListView;

import android.widget.AdapterView;

import android.widget.BaseAdapter;

import android.widget.Button;

import android.widget.ListView;

import android.widget.TextView;

import android.widget.Toast;

import java.util.List;

import mydemo.mycom.demo2.dao.UserDao;

import mydemo.mycom.demo2.entity.UserInfo;

import mydemo.mycom.demo2.service.LoginService;

public class Home extends ActionBarActivity implements View.OnClickListener {

    private ListView lv;

    private Button btn_home_to_login;

    private Button btn_exit;

    private List<UserInfo> list;

    // 设置一个最大的数据条数，超过即不再加载

    private int pageSize=10; //每次获取多少条数据

    // 最后可见条目的索引

    private int pages;//总共有多少页

    private boolean loadfinished = true;

    private MyAdapter myAdapter;

    private View footer;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_home);

        btn_home_to_login = (Button)findViewById(R.id.btn_home_to_login);

        btn_exit = (Button)findViewById(R.id.btn_exit);

        lv = (ListView)findViewById(R.id.lv);

        btn_home_to_login.setOnClickListener(this);

        btn_exit.setOnClickListener(this);

        footer = getLayoutInflater().inflate(R.layout.activity_footer,null);

        UserDao dao = new UserDao(this);

        list = dao.getUserInfo(1,10);

        int total = dao.getTotal();

        System.out.println(total+"===================================");

        pages = total%pageSize==0 ? total/pageSize : total/pageSize+1;

        lv.setOnScrollListener(new MyOnScrollListener());

        myAdapter = new MyAdapter();

        //添加页脚（放在ListView最后）

        lv.addFooterView(footer);

        lv.setAdapter(myAdapter);

        lv.removeFooterView(footer);

        lv.setOnItemClickListener(new MyItemClickListener());

    }

    @Override

    public boolean onCreateOptionsMenu(Menu menu) {

        getMenuInflater().inflate(R.menu.menu_home, menu);

        return true;

    }

    @Override

    public boolean onOptionsItemSelected(MenuItem item) {

        int id = item.getItemId();

        if (id == R.id.action_settings) {

            return true;

        }

        return super.onOptionsItemSelected(item);

    }

    @Override

    public void onClick(View view) {

        switch(view.getId())

        {

            case R.id.btn_home_to_login:

                Intent intent = new Intent();

                intent.setClass(Home.this,Register.class);

                startActivity(intent);

                break;

            case R.id.btn_exit:

                //清除登录数据

                LoginService.removeLoginInfo(this);

                Toast.makeText(this,"退出成功",Toast.LENGTH_SHORT).show();

                Intent toLogin = new Intent();

                toLogin.setClass(Home.this,MainActivity.class);

                startActivity(toLogin);

                break;

        }

    }

    public class MyAdapter extends BaseAdapter

    {

        public int getCount() {

            return list.size();

        }

        @Override

        public Object getItem(int i) {

            return null;

        }

        @Override

        public long getItemId(int i) {

            return 0;

        }

        @Override

        public View getView(int i, View view, ViewGroup viewGroup) {

            UserInfo user = list.get(i);

            View itemview = View.inflate(Home.this,R.layout.activity_item,null);

            TextView tv_id = (TextView)itemview.findViewById(R.id.tv_id);

            TextView tv_username = (TextView)itemview.findViewById(R.id.tv_username);

            TextView tv_password = (TextView)itemview.findViewById(R.id.tv_password);

            tv_id.setText(user.getId()+"");

            tv_username.setText(user.getUsername());

            tv_password.setText(user.getPassword());

            return itemview;

        }

    }

    public class MyItemClickListener implements AdapterView.OnItemClickListener

    {

        @Override

        public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {

            ListView lView = (ListView)lv;

            TextView tv_id = (TextView)view.findViewById(R.id.tv_id);

            TextView tv_username = (TextView)view.findViewById(R.id.tv_username);

            TextView tv_password = (TextView)view.findViewById(R.id.tv_password);

            String id = tv_id.getText().toString();

            String username = tv_username.getText().toString();

            String password = tv_password.getText().toString();

            Toast.makeText(getApplicationContext(), id+","+username, Toast.LENGTH_SHORT).show();

            //不同的activity之间的传值

            Intent intent = new Intent();

            intent.putExtra("username",username);

            intent.putExtra("password",password);

            intent.putExtra("id",id);

            intent.setClass(Home.this,Edit.class);

            startActivity(intent);

        }

    }

    public class MyOnScrollListener implements AbsListView.OnScrollListener

    {

        @Override

        public void onScrollStateChanged(AbsListView absListView, int scrollState) {

        }

        @Override

        public void onScroll(AbsListView absListView, int firstVisibleItem, int visibleItemCount, int totalItemCount) {

            int lastItemIndex = lv.getLastVisiblePosition(); //获取当前屏幕最后的Item的id

            System.out.println("====lastItemIndex:"+lastItemIndex);

            System.out.println("====totalItemCount:"+totalItemCount);

            if(lastItemIndex>0&&(lastItemIndex+1)==totalItemCount) //达到数据的最后一条记录

            {

                //当前页

                int currentpage = totalItemCount%pageSize==0 ? totalItemCount /pageSize :totalItemCount /pageSize+1;

                final int nextpage = currentpage +1; //下一页

                System.out.println("================currentpage:"+currentpage);

                System.out.println("================nextpage:"+nextpage);

                if(nextpage<=pages && loadfinished)

                {

                    loadfinished = false;

                    lv.addFooterView(footer);

                    new Thread(new Runnable() {

                        @Override

                        public void run() {

                            try{

                                Thread.sleep(3000);

                            }

                             catch (Exception e)

                             {

                             }

                            UserDao dao = new UserDao(Home.this);

                            List<UserInfo> result = dao.getUserInfo(nextpage,pageSize);

                            handler.sendMessage(handler.obtainMessage(100,result));

                        }

                    }).start();

                }

            }

        }

        Handler handler = new Handler() {

            public void handleMessage(Message msg)

            {

                list.addAll((List<UserInfo>)msg.obj);

                //告诉ListView数据已经发生改变，要求ListView更新界面显示

                myAdapter.notifyDataSetChanged();

                if(lv.getFooterViewsCount()>0)

                {

                    lv.removeFooterView(footer);

                }

                loadfinished = true;

;            }

        };

    }

}

5.DAO.java

public List<UserInfo> getUserInfo(int pageIndex,int pageSize)

    {

        SQLiteDatabase db = helper.getWritableDatabase();

        List<UserInfo> list = new ArrayList<UserInfo>();

        String sql = "select * from user order by id asc limit "+(pageIndex-1)*pageSize+","+pageSize;

        System.out.println("sql=======:"+sql+",pageIndex:"+pageIndex);

        Cursor cursor = db.rawQuery("select * from user order by id asc limit ?,?",new String[]{((pageIndex-1)*pageSize)+"",pageSize+""});

        while(cursor.moveToNext())

        {

            int id = cursor.getInt(cursor.getColumnIndex("id"));

            String username = cursor.getString(cursor.getColumnIndex("username"));

            String password = cursor.getString(cursor.getColumnIndex("password"));

            UserInfo userInfo = new UserInfo(id,username,password);

            list.add(userInfo);

        }

        cursor.close();

        db.close();

        return list;

    }

5.Entity.java

package mydemo.mycom.demo2.entity;

public class UserInfo {

    private int id;

    private String username;

    private String password;

    public UserInfo()

    { }

    public UserInfo(int id, String username, String password) {

        this.id = id;

        this.username = username;

        this.password = password;

    }

    public int getId() {

        return id;

    }

    public void setId(int id) {

        this.id = id;

    }

    public String getUsername() {

        return username;

    }

    public void setUsername(String username) {

        this.username = username;

    }

    public String getPassword() {

        return password;

    }

    public void setPassword(String password) {

        this.password = password;

    }

}

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