1、首先先建立一个DatabaseHelper类，继承自SQLiteOpenHelper，用于建立数据库，并可更新数据库例如我新建了两张表
public class DatabaseHelper extends SQLiteOpenHelper {
private static DatabaseHelper _databaseHelper;
private static final String TAG = DatabaseHelper.class.getSimpleName();
public synchronized static DatabaseHelper getInstance(Context context)
{
if(_databaseHelper==null)
{
_databaseHelper = new DatabaseHelper(context,"cgjlb",null,2);
}
return _databaseHelper;
}
public synchronized static void destoryInstance(){
if(_databaseHelper!=null){
_databaseHelper=null;
public DatabaseHelper(@Nullable Context context, @Nullable String name, @Nullable SQLiteDatabase.CursorFactory factory, int version) {
super(context, name, factory, version);
@Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {
//主表记录
String sql = "create table t_share(_id integer primary key autoincrement,sharenum text,sharename text,shareprice real,sharelastprice real,addtime text,uptime text,bl real)";
sqLiteDatabase.execSQL(sql);
//记录历史表
sql = "create table t_sharehis(_id integer primary key autoincrement,shareid integer, shareprice real,uptime text)";
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
Log.d(TAG, "onUpgrade: upddatabase");
sqLiteDatabase.execSQL("drop table t_share");
sqLiteDatabase.execSQL("drop table t_sharehis");
onCreate(sqLiteDatabase);
}2、编写数据库具体操作类、增删改查我都写了
public class ShareDbService {
SQLiteDatabase db = null;
DatabaseHelper databaseHelper;
private static final String TAG = ShareDbService.class.getSimpleName();
public ShareDbService(Context context) {
databaseHelper = DatabaseHelper.getInstance(context);
db = databaseHelper.getWritableDatabase();
}
public void addShareInfo(ShareBean shareBean)
{
int Id = getShareId(shareBean.getShareNum());
if(Id==-1) {
ContentValues values = new ContentValues();
values.put("sharenum", shareBean.getShareNum());
values.put("sharename", shareBean.getShareName());
values.put("shareprice", shareBean.getSharePrice());
values.put("sharelastprice", shareBean.getShareLastPrice());
values.put("uptime", shareBean.getUptime());
values.put("addtime",shareBean.getAddtime());
double shareprice = shareBean.getSharePrice();
double sharelastprice = shareBean.getShareLastPrice();
double bl = (sharelastprice-shareprice)/shareprice*100;
values.put("bl", new DecimalFormat("0.00").format(bl));
db = databaseHelper.getWritableDatabase();
db.insert("t_share", null, values);
ShareHisBean shareHisBean = new ShareHisBean();
shareHisBean.setShareId(getShareId(shareBean.getShareNum()));
shareHisBean.setSharePrice(shareBean.getSharePrice());
shareHisBean.setUpTime(shareBean.getUptime());
addShareHis(shareHisBean);
db.close();
}
private void addShareHis(ShareHisBean shareHisBean){
ContentValues values = new ContentValues();
values.put("shareid", shareHisBean.getShareId());
values.put("shareprice", shareHisBean.getSharePrice());
values.put("uptime", shareHisBean.getUptime());
db.insert("t_sharehis", null, values);
db.close();
public void refreshShare(ShareHisBean shareHisBean,double sharePrice){
try {
//更新信息主表
values.put("uptime", shareHisBean.getUptime());
values.put("sharelastprice", shareHisBean.getSharePrice());
String[] args = {String.valueOf(shareHisBean.getShareId())};
double sharelastprice = shareHisBean.getSharePrice();
double bl = (sharelastprice - sharePrice) / sharePrice * 100;
values.put("bl", bl);
db.update("t_share", values, "_Id=?", new String[]{String.valueOf(shareHisBean.getShareId())});
//添加记录
values = new ContentValues();
values.put("shareid", shareHisBean.getShareId());
values.put("shareprice", shareHisBean.getSharePrice());
db.insert("t_sharehis", null, values);
}catch(Exception ex){
ex.printStackTrace();
finally {
public void delShare(String Id){
db.delete("t_share","_Id=?",new String[]{Id});
db.delete("t_sharehis","shareid=?",new String[]{Id});
private int getShareId(String shareNum) {
db = databaseHelper.getReadableDatabase();
String sql = "select _Id from t_share where sharenum='" + shareNum + "'";
int Id = -1;
Cursor cursor = db.rawQuery(sql, null);
if (cursor != null) {
while (cursor.moveToNext()){
Id = cursor.getInt(0);
}
cursor.close();
return Id;
public List<ShareBean> getShareList(){
List<ShareBean> shareBeans = new ArrayList<>();
String sql = "select _id,sharenum,sharename,shareprice,sharelastprice,uptime,addtime,bl from t_share order by _Id desc";
ShareBean shareBean = new ShareBean();
shareBean.set_Id(cursor.getInt(0));
shareBean.setShareNum(cursor.getString(1));
shareBean.setShareName(cursor.getString(2));
shareBean.setSharePrice(cursor.getDouble(3));
shareBean.setShareLastPrice(cursor.getDouble(4));
shareBean.setUptime(cursor.getString(5));
shareBean.setAddtime(cursor.getString(6));
shareBean.setBl(cursor.getDouble(7));
shareBeans.add(shareBean);
return shareBeans;
public List<ShareHisBean> getShareListHis(int ShareId){
List<ShareHisBean> shareHisBeans = new ArrayList<>();
String sql = "select _id,shareid,shareprice,uptime from t_sharehis where shareid='"+String.valueOf(ShareId)+"' order by _id desc";
ShareHisBean shareHisBean = new ShareHisBean();
shareHisBean.set_Id(cursor.getInt(0));
shareHisBean.setShareId(cursor.getInt(1));
shareHisBean.setSharePrice(cursor.getDouble(2));
shareHisBean.setUpTime(cursor.getString(3));
shareHisBeans.add(shareHisBean);
return shareHisBeans;
public ShareBean getShareInfo(int ShareId) {
ShareBean shareBean = new ShareBean();
//_id integer primary key autoincrement,sharenum text,sharename text,shareprice real,sharelastprice real,addtime text,uptime text,bl real
String sql = "select _id,sharenum,sharename,shareprice,sharelastprice,addtime,uptime,bl from t_share where _Id='"+String.valueOf(ShareId)+"'";
if (cursor.moveToNext()){
shareBean.setAddtime(cursor.getString(5));
shareBean.setUptime(cursor.getString(6));
return shareBean;
}3、实际中的应用，就举一个例子吧，数据库操作不用开新线程，直接在主线程里弄就行
ShareDbService shareDbService = new ShareDbService(getContext());
shareDbService.delShare(String.valueOf(shareBean.get_Id()));4、需要注意的是SQLite不支持多线程，最好是能批量修改，否则很麻烦，如果一定要多线程 ，比如循环请求网络更新数据库时，可以使用CountDownLatch，先将数据弄在一个集合里，等子线程全部执行完成后，再更新数据库。此方法具体应用如下
先声明一个变量
CountDownLatch latch;实际应用代码
//设置多线程 个数，一共用多少个线程一定要写清楚，后面是要减的。
latch = new CountDownLatch(count);
for (int i = 0; i < count; i++) {
new Thread(()-> {
try {
//网络请求等操作
} catch (Exception e) {
e.printStackTrace();
} finally {
//这里会自动减1操作，一定要写。
latch.countDown();
}
}).start();
};
try {
latch.await();
//最后执行主程序，比如更新数据库
Toast.makeText(getContext(), "刷新成功", Toast.LENGTH_SHORT).show();
} catch (InterruptedException e) {
e.printStackTrace();
}到此这篇关于Android在Sqlite3中的应用及多线程使用数据库的建议的文章就介绍到这了,更多相关android Sqlite3多线程内容请搜索编程网以前的文章或继续浏览下面的相关文章希望大家以后多多支持编程网！
