android ListView 分页加载数据
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; } }
