android listview scroll滑屏显示sqlite分页，类似聊天记录，listview动态添加sqlite分页数据

前言：最近做基于openfire聊天(仿QQ、微信)翻页查看聊天记录，为此做了根据时间倒序查看聊天记录，先声明这demo是根据id来倒序(原理和时间倒序一样)

1，主界面MainActivity.class

public class MainActivity extends Activity implements OnScrollListener{private ProgressBar loadInfo;private ListView listView;private LinearLayout loadLayout;private ArrayList<String> items;private DatabaseService service;private int currentPage = 1; //默认在第一页private static final int lineSize =10;    //每次显示数 private int allRecorders = 0;  //全部记录数private int pageSize = 1;  //默认共一页private Aleph0 baseAdapter;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);listView = (ListView) findViewById(R.id.listview);service = new DatabaseService(this);//创建一个角标线性布局用来显示"正在加载"loadLayout = new LinearLayout(this);loadLayout.setGravity(Gravity.CENTER);//定义一个ProgressBar表示“正在加载”loadInfo = new ProgressBar(this,null,android.R.attr.progressBarStyleSmall);//增加组件 loadLayout.addView(loadInfo, new LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT));//增加到listView头部listView.addHeaderView(loadLayout);listView.setOnScrollListener(this);showAllData();}/** * 读取全部数据 */public void showAllData(){allRecorders = service.getCount();//计算总页数pageSize = (allRecorders + lineSize -1) / lineSize;  items = service.getAllItems(currentPage, lineSize);Collections.reverse(items);  //倒序baseAdapter = new Aleph0();listView.setAdapter(baseAdapter);listView.setSelection(items.size());//直接定位到最底部}int firstItem=-1;@Overridepublic void onScroll(AbsListView absView, int firstVisibleItem,int visibleItemCount, int totalItemCount) {firstItem=firstVisibleItem;}@Overridepublic void onScrollStateChanged(AbsListView view, int scorllState) {if (firstItem==0&& currentPage < pageSize&& scorllState == OnScrollListener.SCROLL_STATE_IDLE) {// 不再滚动Log.e("log", "滑到第一位");currentPage++;// 增加数据appendDate();}}/** * 增加数据 */private void appendDate(){final ArrayList<String> additems = service.getAllItems(currentPage, lineSize);Collections.reverse(additems);baseAdapter.setCount(baseAdapter.getCount() + additems.size());//判断，如果到了最末尾则去掉“正在加载”if(allRecorders == baseAdapter.getCount()){listView.removeHeaderView(loadLayout);}items.addAll(0, additems);baseAdapter.notifyDataSetChanged();listView.setSelection(additems.size());}class Aleph0 extends BaseAdapter {int count = lineSize; public int getCount() {return count;} public void setCount(int count){this.count = count;}public Object getItem(int pos) {return pos;}public long getItemId(int pos) {return pos;}public View getView(int pos, View v, ViewGroup p) {TextView view = new TextView(MainActivity.this);view.setTextSize(60);if(items != null){view.setText(items.get(pos));}else{view.setText(pos);}return view;}}}

2,主界面布局文件activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:orientation="vertical" >    <ListView        android:id="@+id/listview"        android:layout_width="fill_parent"        android:layout_height="fill_parent" /></LinearLayout>

3,数据库操作类

public class DatabaseService { private Context mContext;private MyDBOpenHelper dbHelper;public DatabaseService(Context context) {mContext = context;dbHelper = new MyDBOpenHelper(mContext);}// 添加public void insert(String title) {SQLiteDatabase db = dbHelper.getWritableDatabase();String sql = "insert into database(title) values(?)";db.execSQL(sql, new String[] { title });}// 删除public void delete(String title) {SQLiteDatabase db = dbHelper.getWritableDatabase();String sql = "delete from database where title = ?";db.execSQL(sql, new String[] { title });}// 查找public ArrayList<String> find(int id) {SQLiteDatabase db = dbHelper.getWritableDatabase();String sql = "select * from database where _id = ? ";Cursor c = db.rawQuery(sql, new String[] { String.valueOf(id) });ArrayList<String> titles = new ArrayList<String>();if (c.moveToNext()) {String title = c.getString(c.getColumnIndexOrThrow(MyDBOpenHelper.FIELD_TITLE));titles.add(title);return titles;}// 不用忘记关闭Cursor。c.close();return null;}// 更新public void upDate(int id, String title) {SQLiteDatabase db = dbHelper.getWritableDatabase();String sql = "update database set title =? where _id = ?";db.execSQL(sql,new String[] { String.valueOf(title), String.valueOf(id) });}// 查询记录的总数public int getCount() {SQLiteDatabase db = dbHelper.getWritableDatabase();String sql = "select count(*) from database";Cursor c = db.rawQuery(sql, null);c.moveToFirst();int length = c.getInt(0);c.close();return length;}/** * 分页查询 *  * @param currentPage 当前页 * @param pageSize 每页显示的记录 * @return 当前页的记录 */public ArrayList<String> getAllItems(int currentPage, int pageSize) {int firstResult = (currentPage - 1) * pageSize;int maxResult = currentPage * pageSize;SQLiteDatabase db = dbHelper.getWritableDatabase();String sql = "select * from database order by  _id desc limit ?,? ";Cursor mCursor = db.rawQuery(sql,new String[] { String.valueOf(firstResult),String.valueOf(pageSize) });ArrayList<String> items = new ArrayList<String>();int columnCount  = mCursor.getColumnCount();while (mCursor.moveToNext()) {String item = mCursor.getString(mCursor.getColumnIndexOrThrow(MyDBOpenHelper.FIELD_TITLE));items.add(item);}//不要关闭数据库return items;}}

4，效果图

5，下载地址：http://download.csdn.net/detail/shi508181017/8297955