Android知识点八(sqllite数据库操作，以及sqlite+handler+XListView实现上拉刷新下拉加载)

    1.DBHelper类数据库辅助类:

    public class DBHelper extends SQLiteOpenHelper {
private static final int version = 1;
public DBHelper(Context context, String name) {
super(context, name, null, version);
}

@Override
public void onCreate(SQLiteDatabase db) {
String sql = "create table if not exists Helper("
+ "id integer primary key autoincrement," + "username varchar,"
+ "userage varchar," + "userPhone varchar," + "userQQ varchar)";
try {
db.execSQL(sql);
} catch (Exception e) {
e.printStackTrace();
}

}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
if (oldVersion != newVersion) {
db.execSQL("DROP TABLE IF EXISTS Helper");
onCreate(db);
}
}

}2.BDDAO逻辑类:
public class BDDAO {
private static final String DATABASE_NAME = "Helper.db";
public static final String ROOT = Environment.getExternalStorageDirectory()
.getPath();
private Context mContext;
private DBHelper mDBHelper;

public BDDAO(Context context) {
this.mContext = context;
String name = DATABASE_NAME;
File file = Environment.getExternalStorageDirectory();
if (file.canWrite()) {
String path = ROOT + File.separator + "Helper/";
File dbDir = new File(path);
if (!dbDir.exists()) {
dbDir.mkdirs();
}
name = path + name;
}
this.mDBHelper = new DBHelper(mContext, name);
}

/**
* 关闭DB
*/
public void close() {
if (mDBHelper != null) {
mDBHelper.close();
}
}

/**
* 获取所有数据
*/
public List<User> getUserList() {
List<User> groups = new ArrayList<User>();
SQLiteDatabase db = mDBHelper.getReadableDatabase();
try {
Cursor cur = db.query("Helper", new String[] { "*" }, null, null,
null, null, null);
while (cur.moveToNext()) {
User info = makeUserCursor(cur);
groups.add(info);
}
cur.close();
} catch (Exception e) {
e.printStackTrace();
} finally {
db.close();
}
return groups;
}

/**
* 根据查询条件查询
*
* @param selection
* 数据库字段
* @param param
* 实体字段
* @return
*/
public List<User> queryUser(String selection, String[] param) {
List<User> groups = new ArrayList<User>();
SQLiteDatabase db = mDBHelper.getWritableDatabase();
try {

Cursor cur = db.query("Helper", new String[] { "*" }, selection,
param, null, null, null);

while (cur.moveToNext()) {
User info = makeUserCursor(cur);
groups.add(info);
}
cur.close();
} catch (Exception e) {
e.printStackTrace();
} finally {
db.close();
}
return groups;
}

/**
* 分页
* @param pagenum
* @param pageSize
* @return
*/
public List<User> queryUser(int pagenum, int pageSize) {
List<User> groups = new ArrayList<User>();
SQLiteDatabase db = mDBHelper.getWritableDatabase();
try {
Cursor cur = db
.rawQuery(
"select id,username,userage,userPhone,userQQ from Helper limit ?,?",
new String[] { (pagenum - 1) * pageSize + "",
pageSize + "" });
while (cur.moveToNext()) {
User info = makeUserCursor(cur);
groups.add(info);
}
cur.close();
} catch (Exception e) {
e.printStackTrace();
} finally {
db.close();
}
return groups;
}

/**
* 根据查询条件查询(有排序)
*
* @param selection
* 数据库字段
* @param param
* 实体字段
* @param orderby
* 排序
* @return
*/
public List<User> queryUser(String selection, String[] param, String orderby) {
List<User> groups = new ArrayList<User>();
SQLiteDatabase db = mDBHelper.getWritableDatabase();
try {
Cursor cur = db.query("Helper", new String[] { "*" }, selection,
param, null, null, orderby);

while (cur.moveToNext()) {
User info = makeUserCursor(cur);
groups.add(info);
}
cur.close();
} catch (Exception e) {
e.printStackTrace();
} finally {
db.close();
}

return groups;
}

private User makeUserCursor(Cursor cur) {
User u = new User();
u.setUserage(cur.getString(cur.getColumnIndex("userage")));
u.setUsername(cur.getString(cur.getColumnIndex("username")));
u.setUserphone(cur.getString(cur.getColumnIndex("userPhone")));
u.setUserqq(cur.getString(cur.getColumnIndex("userQQ")));
return u;
}

/**
* 新增
*
* @param u
* @return
*/
public long addUser(User u) {
long rowid = 0;
SQLiteDatabase db = mDBHelper.getWritableDatabase();
ContentValues values = makeContentValues(u);
try {
db.beginTransaction();
rowid = db.insert("Helper", null, values);
db.setTransactionSuccessful();
} catch (Exception e) {
e.printStackTrace();
} finally {
db.endTransaction();
db.close();
}
return rowid;
}

private ContentValues makeContentValues(User u) {
ContentValues mContentValues = new ContentValues();
mContentValues.put("userage", u.getUserage());
mContentValues.put("username", u.getUsername());
mContentValues.put("userPhone", u.getUserphone());
mContentValues.put("userQQ", u.getUserqq());
return mContentValues;
}

/**
* 更新
*
* @param u
* @return
*/
public boolean updateUser(User u) {
boolean b_result = false;

SQLiteDatabase db = mDBHelper.getWritableDatabase();
ContentValues values = makeContentValues(u);

try {
db.beginTransaction();
long rowid = db.update("Helper", values, "id=?",
new String[] { String.valueOf(u.getId()) });
db.setTransactionSuccessful();
if (rowid > 0)
b_result = true;
} catch (Exception e) {
e.printStackTrace();
} finally {
db.endTransaction();
db.close();
}

return b_result;
}

/**
* 删除(根据ID)
*
* @param id
* @return
*/
public boolean deleteUser(int id) {
boolean b_result = false;
SQLiteDatabase db = mDBHelper.getWritableDatabase();
try {
db.beginTransaction();
long rowid = db.delete("Helper", "Id=?",
new String[] { String.valueOf(id) });
db.setTransactionSuccessful();
if (rowid > 0)
b_result = true;
} catch (Exception e) {
e.printStackTrace();
} finally {
db.endTransaction();
db.close();
}
return b_result;
}

/**
* 根据查询条件删除
*
* @param selection
* @param param
* @return
*/
public boolean deleteUser(String selection, String[] param) {
boolean b_result = false;
SQLiteDatabase db = mDBHelper.getWritableDatabase();
try {
db.beginTransaction();
long rowid = db.delete("Helper", selection, param);
db.setTransactionSuccessful();
if (rowid > 0)
b_result = true;
} catch (Exception e) {
e.printStackTrace();
} finally {
db.endTransaction();
db.close();
}
return b_result;
}

/**
* 是否存在这条记录
*
* @param selection
* @param param
* @return
*/
public boolean isExit(String selection, String[] param) {
SQLiteDatabase db = mDBHelper.getWritableDatabase();
try {
Cursor cur = db.query("Helper", new String[] { "*" }, selection,
param, null, null, null);

while (cur.moveToNext()) {
return true;
}
cur.close();
} catch (Exception e) {
e.printStackTrace();
} finally {
db.close();
}
return false;
}

}3.UI展示类:
public class ListUserActivity extends Activity {
private XListView mXListView;
private Handler mHandler;
private BDDAO mBDDAO;
private UserAdapter mUserAdapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.user_list_act);
mHandler = new Handler();
mBDDAO = new BDDAO(this);
mXListView = (XListView) findViewById(R.id.xlistview);
mXListView.setOnXListViewListener(new OnXListViewListener() {
@Override
public void onRefresh(XListView v) {
v.setTag(String.valueOf("1"));
this.onLoadMore(v);
}

@Override
public void onLoadMore(XListView v) {
mHandler.post(new Runnable() {
@Override
public void run() {
List<User> list = mBDDAO.queryUser(Integer.valueOf(String.valueOf(mXListView.getTag())),5);
if (list.size() > 0) {
int page = Integer.parseInt(String.valueOf(mXListView.getTag()));
mXListView.setTag(page + 1);
if (page == 1) {
mUserAdapter = new UserAdapter(ListUserActivity.this, list);
mXListView.setAdapter(mUserAdapter);
mXListView.onRefreshComplete();
} else {
if (list.size() > 0) {
mUserAdapter.addAll(list);
mXListView.onLoadMoreComplete();
} else {
mXListView.onLoadMoreComplete();
Toast.makeText(ListUserActivity.this,"没有更多的数据了...", Toast.LENGTH_LONG).show();
}
}
}else{
mXListView.onLoadMoreComplete();
Toast.makeText(ListUserActivity.this,"没有更多的数据了...", Toast.LENGTH_LONG).show();
}
}
});
}
});

initData();
}

void initData() {
UIHelper.showLoadDialog(this, "正在加载...");
mHandler.post(new Runnable() {
@Override
public void run() {
List<User> list = mBDDAO.queryUser(Integer.valueOf(String.valueOf(mXListView.getTag())), 5);
mUserAdapter = new UserAdapter(ListUserActivity.this, list);
mXListView.setAdapter(mUserAdapter);
UIHelper.cloesLoadDialog();
}
});
}其中的Adapter,bean,xml就不给出了比较简单,XListView可自行在网上下载!