Android Studio SQLite Manage
一、类DBHelper ：
public class DBHelper extends SQLiteOpenHelper {
private static final String CREATE_TABLE_START_SQL = "CREATE TABLE IF NOT EXISTS ";
private static final String CREATE_TABLE_PRIMIRY_SQL = " integer primary key autoincrement,";
public DBHelper(Context context, String dbname, SQLiteDatabase.CursorFactory factory,int version)
{
super(context,dbname,null,1);
}
//数据库第一次创建时被调用
@Override
public void onCreate(SQLiteDatabase db) {
//CREATE TABLE person(personid INTEGER PRIMARY KEY AUTOINCREMENT,name VARCHAR(20))
StringBuffer mealSql = new StringBuffer();
mealSql.append(CREATE_TABLE_START_SQL).append(" meals ").append(" ( ");
mealSql.append(" id").append(CREATE_TABLE_PRIMIRY_SQL);
mealSql.append(" MealID").append(" varchar(32) default \"\" ,");
mealSql.append(" MealName").append(" varchar(150) default \"\" ,");
mealSql.append(" MState").append(" varchar(10) default \"\" ,");
mealSql.append(" TagID").append(" varchar(20) default \"\" ,");
mealSql.append(" ImgUrl").append(" varchar(250) default \"\" ,");
mealSql.append(" SellPrice").append(" double default 0 ,");
mealSql.append(" ForIndex").append(" double default 0 ,");
mealSql.append(" JLUnit").append(" double default 1 ,");
mealSql.append(" JLPrice").append(" double default 0 ");
mealSql.append(" )");
db.execSQL(mealSql.toString());
}
//软件版本号发生改变时调用
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
//db.execSQL("ALTER TABLE person ADD phone VARCHAR(12) NULL");
}
}
二、类DBManager
public class DBManager {
private static DBManager instance;
private static SQLiteOpenHelper mDBHelper;
private SQLiteDatabase mDatabase;
private AtomicInteger mOpenCounter = new AtomicInteger();
/**
*单例模式，初始化DBManager
* @return
*/
public static synchronized DBManager getInstance()
{
if(instance==null){
instance=new DBManager() ;
}
return instance;
}
/**
*数据库初始化
* @param context
*/
public void init(Context context)
{
if(context==null) {return;}
if(mDBHelper==null)
{
mDBHelper=new DBHelper(context.getApplicationContext(),"meals.db",null,1);
}
}
/**
* 释放数据库
*/
public void release() {
if (mDBHelper != null) {
mDBHelper.close();
mDBHelper = null;
}
instance = null;
}
/**
* 打开数据库
*/
public synchronized SQLiteDatabase openDatabase() {
if (mOpenCounter.incrementAndGet() == 1) {
// Opening new database
try {
mDatabase = mDBHelper.getWritableDatabase();
} catch (Exception e) {
//Log.e(TAG, "openDatabase e = " + e.getMessage());
Logger.d("openDatabase e "+e.getMessage());
mDatabase = mDBHelper.getReadableDatabase();
}
}
return mDatabase;
}
/**
* 关闭数据库
*/
public synchronized void closeDatabase() {
if (mOpenCounter.decrementAndGet() == 0) {
// Closing database
mDatabase.close();
}
}
private void closeCursor(Cursor cursor) {
if (cursor != null) {
try {
cursor.close();
} catch (Throwable e) {
//Log.e(TAG, "closeCursor e = " + e.getMessage());
}
}
}
/**
* 保持菜品，如果已经存在菜品编号则更新，否则新增
* @param meal
* @return
*/
public ResponseBean addmeal(dishmeal meal) {
Cursor cursor =null;
ResponseBean res = new ResponseBean();
res.setSucceed(false);
try {
if (mDBHelper == null) {
res.setData("未初始化 mDBHelper");
return res;
}
SQLiteDatabase db = mDBHelper.getReadableDatabase();
cursor = db.rawQuery("SELECT * FROM meals WHERE MealID = ?",
new String[]{meal.getMealID()});
//存在数据才返回true
if (cursor == null) {
res.setData("cursor==null");
return res;
}
if (cursor.getCount() > 0) {
//存在该菜品,则修改
mDatabase = mDBHelper.getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put("ForIndex", meal.getForIndex());
// cv.put("ImgUrl", meal.getImgUrl());
cv.put("JLPrice", meal.getJLPrice());
cv.put("JLUnit", meal.getJLUnit());
cv.put("MealID", meal.getMealID());
cv.put("MealName", meal.getMealName());
cv.put("MState", meal.getMState());
cv.put("SellPrice", meal.getSellPrice());
cv.put("TagID", meal.getTagID());
//参数依次是表名，修改后的值，where条件，以及约束，如果不指定三四两个参数，会更改所有行
int rowId = mDatabase.update("meals", cv, "MealID = ?", new String[]{meal.getMealID()});
Logger.d("update meal rowId:"+rowId);
if (rowId < 0) {
res.setData("更新失败，" + rowId);
closeCursor(cursor);
//return res;
} else {
res.setSucceed(true);
res.setData("更新数据成功");
closeCursor(cursor);
//return res;
}
} else {
mDatabase = mDBHelper.getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put("ForIndex", meal.getForIndex());
// cv.put("ImgUrl", meal.getImgUrl());
cv.put("JLPrice", meal.getJLPrice());
cv.put("JLUnit", meal.getJLUnit());
cv.put("MealID", meal.getMealID());
cv.put("MealName", meal.getMealName());
cv.put("MState", meal.getMState());
cv.put("SellPrice", meal.getSellPrice());
cv.put("TagID", meal.getTagID());
long rowId = mDatabase.insert("meals", null, cv);
Logger.d("insert meal rowId:"+rowId);
if (rowId < 0) {
res.setData("插入失败，" + rowId);
//closeCursor(cursor);
//return res;
} else {
res.setSucceed(true);
res.setData("插入数据成功");
//closeCursor(cursor);
//return res;
}
}
//return res ;
} catch (Exception ex) {
res.setData("出错了，" + ex.getMessage());
//closeCursor(cursor);
}
finally {
closeCursor(cursor);
}
return res;
}
/**
* 查询出识别的菜品详细信息
* @param mlst
* @return
*/
public List getmeal(List mlst) {
Cursor cursor = null;
List meallist = new ArrayList<>();
try {
if(mDBHelper==null){
return null;
}
SQLiteDatabase db=mDBHelper.getReadableDatabase();
String where =null;//"MealID in (?,?,?) ";
String[] whereValue =null;//{"11","10","12"};
if(mlst!=null && mlst.size()>0) {
where ="";
whereValue = mlst.toArray(new String[0]);//. " MealID"
for(int i=0;i 0 && cursor.moveToNext()) {
//int dbId = cursor.getInt(cursor.getColumnIndex("_id"));
double ForIndex = cursor.getDouble(cursor.getColumnIndex("ForIndex"));
String ImgUrl = cursor.getString(cursor.getColumnIndex("ImgUrl"));
double JLPrice = cursor.getDouble(cursor.getColumnIndex("JLPrice"));
double JLUnit = cursor.getDouble(cursor.getColumnIndex("JLUnit"));
String MealID = cursor.getString(cursor.getColumnIndex("MealID"));
String MealName = cursor.getString(cursor.getColumnIndex("MealName"));
String MState = cursor.getString(cursor.getColumnIndex("MState"));
double SellPrice = cursor.getDouble(cursor.getColumnIndex("SellPrice"));
String TagID = cursor.getString(cursor.getColumnIndex("TagID"));
dishmeal meal=new dishmeal();
meal.setForIndex(ForIndex);
meal.setImgUrl(ImgUrl);
meal.setJLPrice(JLPrice);
meal.setJLUnit(JLUnit);
meal.setMealID(MealID);
meal.setMealName(MealName);
meal.setMState(MState);
meal.setSellPrice(SellPrice);
meal.setTagID(TagID);
meallist.add(meal);
}
} catch (Exception ex) {
Logger.d("getmeal Error：" +ex.getMessage());
} finally {
closeCursor(cursor);
}
return meallist;
}
public ResponseBean updatemealimg(String mealid,String imgpath) {
Cursor cursor = null;
ResponseBean res = new ResponseBean();
res.setSucceed(false);
try {
if (mDBHelper == null) {
res.setData("未初始化 mDBHelper");
return res;
}
//存在该菜品,则修改
mDatabase = mDBHelper.getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put("ImgUrl", imgpath);
cv.put("MealID", mealid);
//参数依次是表名，修改后的值，where条件，以及约束，如果不指定三四两个参数，会更改所有行
int rowId = mDatabase.update("meals", cv, "MealID = ?", new String[]{mealid});
Logger.d("update meal rowId:" + rowId);
if (rowId < 0) {
res.setData("更新失败，" + rowId);
closeCursor(cursor);
//return res;
} else {
res.setSucceed(true);
res.setData("更新数据成功");
closeCursor(cursor);
//return res;
}
} catch (Exception ex) {
res.setData("出错了，" + ex.getMessage());
//closeCursor(cursor);
} finally {
closeCursor(cursor);
}
return res;
}
}
三、简单调用
DBManager.getInstance().init(context);
List qmlst=new ArrayList<>();
qmlst.add("2146");
List mlst = DBManager.getInstance().getmeal(qmlst);