我已经使用我的应用程序打包了一个数据库，我可以在文件资源管理器中看到正在创建databases文件夹以及workoutsDatabase.sqlite文件。但是，当我查看数据库的内容时，其中唯一的表是android_metadata表。我一直在寻找几个小时，看到很多人有类似的问题，但是，我似乎无法弄清楚正确的解决方案。
有人能发现为什么这些表似乎没有复制过吗？我已经验证了我的资产文件夹中的workoutsDatabase.sqlite。它包含表＆＃34; workout＆＃34;它确实有数据。
WorkoutsDatabaseHelper
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteStatement;
import android.util.Log;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
public class WorkoutsDatabaseHelper extends SQLiteOpenHelper {
private String DATABASE_PATH = "/data/data/com.rcd.myworkouts/databases/";
private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "workoutsDatabase.sqlite";
private static final String TABLE_WORKOUTS = "workouts";
private static final String KEY_ID = "_id";
private static final String KEY_WORKOUT_NAME = "workout_name";
private static final String KEY_LAST_NAME = "last_name";
private static final String KEY_FIRST_NAME = "first_name";
private static final String KEY_MIDDLE_NAME = "middle_name";
private static final String KEY_DESCRIPTION = "description";
private static final String KEY_DATE_ADDED = "date_added";
private static final String KEY_WORKOUT = "workout";
private static final String KEY_MEASUREMENT = "measurement";
private static final String KEY_PHOTO = "photo";
private SQLiteDatabase myDatabase;
private final Context myContext;
public WorkoutsDatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
this.myContext = context;
}
// Creates a empty database on the system and rewrites it with your own database.
public void createDatabase() throws IOException {
boolean dbExist = checkDatabase();
SQLiteDatabase db_Read = null;
if(dbExist) {
// Do nothing - database already exist
} else {
//By calling this method an empty database will be created into the default system path
//of your application so we are gonna be able to overwrite that database with our database.
db_Read = getReadableDatabase();
db_Read.close();
try {
copyDatabase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
//Check if the database already exist to avoid re-copying the file each time you open the application.
//@return true if it exists, false if it doesn't
private boolean checkDatabase() {
SQLiteDatabase checkDB = null;
try {
String myPath = DATABASE_PATH + DATABASE_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
} catch(SQLiteException e) {
// Database doesn't exist yet
}
if (checkDB != null) {
checkDB.close();
}
return checkDB != null ? true : false;
}
/**
* Copies your database from your local assets-folder to the just created empty database in the
* system folder, from where it can be accessed and handled.
* This is done by transfering bytestream.
* */
private void copyDatabase() throws IOException {
getWritableDatabase();
Log.d("Database", "New database is being copied to device!");
try
{
// Open your local db as the input stream
InputStream myInput = myContext.getAssets().open(DATABASE_NAME);
// transfer bytes from the inputfile to the
// Path to the just created empty db
String outFileName = DATABASE_PATH + DATABASE_NAME;
// Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
// Transfer bytes form the inputfile to the output file
byte[] buffer = new byte[1024];
int length;
while((length = myInput.read(buffer)) > 0)
{
myOutput.write(buffer, 0, length);
}
// Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
Log.i("Database", "New database has been copied to device!");
}
catch(IOException e)
{
e.printStackTrace();
}
}
protected Boolean openDatabase() {
if(checkDatabase())
{
// Open the database
String myPath = DATABASE_PATH + DATABASE_NAME;
try
{
Log.i("Database", "Trying to Open Database!");
if(myDatabase != null)
{
if(!myDatabase.isOpen())
{
Log.i("Database", "Database is closed now opening it!");
myDatabase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
}
else
{
Log.i("Database", "Database is already Open!");
}
Log.i("Database", "Database is Opened successfully in OPEN_READWRITE Mode !");
return true;
}
else
{
myDatabase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
Log.i("Database", "Database is Opened successfully in OPEN_READWRITE Mode !");
return true;
}
}
catch(Exception e)
{
Log.e("Database", "Some error occured while opening Database Error:" + e.getMessage());
myDatabase = null;
return false;
}
}
else
try {
copyDatabase();
Log.d("WorkoutsDatabaseHelper.java", "Copy Database..");
} catch (IOException e) {
throw new Error("Error copying database");
}
return false;
}
@Override
public synchronized void close() {
if(myDatabase != null)
myDatabase.close();
super.close();
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}