我在下面有我的代码。它在我的资产文件夹中正确读取了我的 sqlite 数据库文件(我已经使用 SQLite 数据库浏览器创建了) - 将其移动到我设备上的 /data/data/packagename/databases/ 路径,然后我可以使用查询和光标来获取我的信息,效果很好。代码在这里:
public class DatabaseHelper extends SQLiteOpenHelper {
private Context myDbContext;
private static String dbName = "restaurant.db";
private static String outfilePath = "/data/data/dev.mypackage.com/databases/";
private static String path = outfilePath + dbName;
private static SQLiteDatabase db;
public DatabaseHelper(Context context){
super(context, dbName, null, 2);
this.myDbContext = context;
db = openDb();
String s = "select * from menu";
Cursor c = db.rawQuery(s, null);
Log.e("DB Constructor Row count", String.valueOf(c.getCount()).toString());
while(c.moveToNext()){
Log.e("DB Constructor", c.getString(c.getColumnIndex("category")));
Log.e("DB Constructor", c.getString(c.getColumnIndex("menuItem_id")));
Log.e("DB Constructor", c.getString(c.getColumnIndex("title")));
Log.e("DB Constructor", c.getString(c.getColumnIndex("desc")));
Log.e("DB Constructor", c.getString(c.getColumnIndex("price")));
Log.e("DB Constructor", c.getString(c.getColumnIndex("icon")));
}
c.deactivate();
c.close();
}
private void copyDataBase(File dbFile) throws IOException {
try{
InputStream dbStream = myDbContext.getAssets().open(dbName);
OutputStream newDbFile = new FileOutputStream(outfilePath + dbName);
byte[] buffer = new byte[1024];
int length;
while((length = dbStream.read(buffer)) > 0){
newDbFile.write(buffer);
}
newDbFile.flush();
newDbFile.close();
dbStream.close();
}
catch(IOException e){
throw new IOException("trying to copy the database - ERROR: " + e.getMessage());
}
}
private SQLiteDatabase openDb() throws SQLiteException{
File dbFile = myDbContext.getDatabasePath(dbName);
if(!dbFile.exists()){
Log.e("openDb", "file does not exist");
try {
copyDataBase(dbFile);
} catch (IOException e) {
throw new RuntimeException("Error creating source database", e);
}
}
return SQLiteDatabase.openDatabase(path, null, SQLiteDatabase.OPEN_READONLY);
}
public void loadRestaurantInfo(){
}
@Override
public void onCreate(SQLiteDatabase db){
// TODO Auto-generated method stub
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
现在我不得不返回并使用 SQLite 浏览器向其中一个表(在资产文件夹中的数据库中)添加一行信息,但这并没有反映在我的光标输出中 - 我明白为什么会这样- 因为 if(!dbFile.exists()) 失败所以没有复制要做。所以我的问题是 - 我需要添加什么代码才能完成这项工作?我从来没有用代码创建表,所以我看不出 onUpgrade 方法对我有多大用处。