有人可以告诉我如何在重新启动应用程序后使我的数据库不为空：现在，当我重新启动它时它是空的。但我需要保留我插入的数据。
我已经尝试过问这个问题，但没有人告诉我我的错误。
这是我的代码：
public class DataBaseFactory {
private SQLiteDatabase db;
private final Context context;
private SD_util sdUtil;
private static String DB_NAME = "nyam_db.db3";
private static String DB_PATH = "/data/data/com.st.nyam/databases/";
private static String TAG = "DataBaseFactory";
private static int DATABASE_VERSION = 1;
// private final String INSERT_RECEPY =
// "INSERT into RECEPIES ('id', 'recepy', 'author') VALUES (?, ?, ?)";
private final String SELECT_RECIPES = "SELECT * FROM recipes";
private final String SELECT_RECIPE_BY_ID = "SELECT * FROM recipes WHERE ID = ?";
private final String SELECT_COUNT_RECIPE_BY_ID = "SELECT count(*) FROM recipes WHERE ID = ?";
private final String SELECT_STEPS = "SELECT * FROM steps";
private final String SELECT_TABLES = "SELECT name FROM sqlite_master WHERE type= 'table' ORDER BY name";
private final String SELECT_STEPS_BY_ID = "SELECT * FROM steps where recipe_id = ?";
private final String INSERT_STEP = "INSERT INTO steps ('id', 'recipe_id', 'body', 'photo_file_name') VALUES (?,?,?,?) ";
private final String INSERT_RECIPE = "INSERT INTO recipes ('id', 'title', 'description', 'user_id', 'favorites_by', 'main_photo_file_name') VALUES (?,?,?,?,?,?) ";
private final String DELETE_RECIPE = "DELETE FROM recipes WHERE id = ?";
private final String DELETE_STEPS_BY_RECIPEID = "DELETE FROM steps WHERE recipe_id = ?";
public DataBaseFactory(Context ctx) {
context = ctx;
sdUtil = new SD_util();
SQLiteDatabase temp_db = ctx.openOrCreateDatabase(DB_NAME,
Context.MODE_PRIVATE, null);
temp_db.close();
try {
Log.i(TAG, "Copy intenting");
copyDataBase();
} catch (IOException e) {
Log.e(TAG, e.getMessage());
}
Log.i(TAG, "Temp created");
if (db == null) {
db = SQLiteDatabase.openDatabase(DB_PATH + DB_NAME, null,
SQLiteDatabase.OPEN_READWRITE);
}
Log.i(TAG, "Temp opened");
}
private boolean checkDataBase() {
SQLiteDatabase checkDB = null;
try {
String myPath = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READWRITE);
} catch (SQLiteException e) {
// database does't exist yet.
e.printStackTrace();
}
if (checkDB != null) {
checkDB.close();
}
return checkDB != null ? true : false;
}
public void openDataBase() throws SQLException {
// Open the database
String myPath = DB_PATH + DB_NAME;
db = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READONLY);
}
private void copyDataBase() throws IOException {
// Open your local db as the input stream
InputStream myInput = context.getAssets().open("db/" + DB_NAME);
// Path to the just created empty db
String outFileName = DB_PATH + DB_NAME;
// Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
// transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
Log.i(TAG, "Copy data");
// Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
public ArrayList<RecipeGeneral> getRecipes() {
ArrayList<RecipeGeneral> recipes = new ArrayList<RecipeGeneral>();
Cursor c = db.rawQuery(SELECT_RECIPES, null);
Log.d(TAG, "getRecipes()");
if (c != null && c.getCount() > 0) {
c.moveToFirst();
do {
Log.d(TAG, "Getting recipe");
RecipeGeneral recipe = ModelUtil.getRecipeFromCursor(c);
recipes.add(recipe);
Log.d(TAG, "Getting recipe added");
} while (c.moveToNext());
}
c.close();
return recipes;
}
public ArrayList<Step> getStepsByRecipeId(int recipeId)
throws ParseException {
Log.d(TAG, "In getStepsByRecipe");
ArrayList<Step> steps = new ArrayList<Step>();
Cursor c = db.rawQuery(SELECT_STEPS_BY_ID,
new String[] { Integer.toString(recipeId) });
Log.d(TAG, "Get Query getStepsByRecipe");
try {
if (c != null && c.getCount() > 0) {
c.moveToFirst();
do {
Log.d(TAG, "Getting step getStepsByRecipe");
Step step = ModelUtil.getStepFromCursor(c);
steps.add(step);
Log.d(TAG, "Getting step added getStepsByRecipe");
} while (c.moveToNext());
}
} finally {
if (c != null) {
c.close();
}
}
c.close();
return steps;
}
/*
* public ArrayList<Step> getSteps() throws ParseException { ArrayList<Step>
* steps = new ArrayList<Step>(); Cursor c = db.rawQuery(SELECT_STEPS,
* null); if (c != null && c.getCount() > 0) { c.moveToFirst(); do { Step
* step = new Step(); step.setId(c.getInt(c.getColumnIndex("id")));
* step.setRecipe_id(c.getInt(c.getColumnIndex("recipe_id")));
* step.setBody(c.getString(c.getColumnIndex("body")));
* step.setPhoto_file_name
* (c.getString(c.getColumnIndex("photo_file_name")));
* step.setPhoto_content_type
* (c.getString(c.getColumnIndex("photo_content_type")));
* step.setPhoto_file_size(c.getInt(c.getColumnIndex("photo_file_size")));
* step.setPhoto_updated_at(new
* SimpleDateFormat("yyyy.MM.dd G HH:mm:ss").parse
* (c.getString(c.getColumnIndex("photo_updated_at"))));
* step.setCreated_at(new
* SimpleDateFormat("yyyy.MM.dd G HH:mm:ss").parse(c.getString
* (c.getColumnIndex("created_at")))); step.setUpdated_at(new
* SimpleDateFormat
* ("yyyy.MM.dd G HH:mm:ss").parse(c.getString(c.getColumnIndex
* ("updated_at"))));
* step.setPhoto_processing(c.getInt(c.getColumnIndex("photo_processing")));
* steps.add(step); } while (c.moveToNext()); } c.close(); return steps; }
*/
public ArrayList<Recipe> fetchRecipesByQuery(String query)
throws ParseException {
ArrayList<Recipe> recipes = new ArrayList<Recipe>();
Cursor c = db.query(true, "virt", null, "description " + " Match "
+ "'*" + query + "*'", null, null, null, null, null);
try {
Log.i(TAG, "Get Query");
if (c != null && c.getCount() > 0) {
c.moveToFirst();
do {
Log.i(TAG, "Getting recipe");
// Recipe recipe = ModelUtil.getRecipeFromCursor(c);
// recipes.add(recipe);
Log.i(TAG, "Getting recipe added");
} while (c.moveToNext());
}
} finally {
if (c != null) {
c.close();
}
}
return recipes;
}
public void addRecipeToFavorites(Recipe recipe, Bitmap bitmap) {
Log.d(TAG, "addRecipeToFavorites begin");
if (!isRecipeExists(recipe.getId())) {
ArrayList<Step> steps = recipe.getSteps();
Log.d(TAG, "Adding recipe to favorites addRecipeToFavorites()");
sdUtil.saveRecipeImage(bitmap, recipe.getImg_url());
db.execSQL(
INSERT_RECIPE,
new String[] { Integer.toString(recipe.getId()),
recipe.getTitle(), recipe.getDescription(),
recipe.getUser(),
Integer.toString(recipe.getFavorites_by()),
recipe.getImg_url() });
if (recipe.getSteps() != null) {
for (Step step : steps) {
Object[] params = new Object[] { step.getImg_url() };
new DownloadImageStep().execute(params);
Log.d(TAG, "Adding step to favorites addRecipeToFavorites()");
addStepToFavorites(step, recipe.getId());
}
} else {
Log.d(TAG, "No steps in this recipe");
}
} else {
Log.d(TAG, "Recipe already added");
}
}
private void addStepToFavorites(Step step, int recipe_id) {
db.execSQL(
INSERT_STEP,
new String[] { Integer.toString(step.getNumber()),
Integer.toString(recipe_id), step.getInstruction(),
step.getImg_url(), });
}
public void deleteRecipeFromFavorites(Recipe recipe) {
Log.d(TAG, "deleteRecipeFromFavorites begin");
if (isRecipeExists(recipe.getId())) {
if (recipe.getSteps() != null) {
for (Step step : recipe.getSteps()) {
Log.d(TAG, "Boolean stepimage deleted = " + sdUtil.deleteImageFromSD(step.getImg_url().replace('/', '&')));
}
deleteStepsFromFavoritesByRecipeId(recipe.getId());
} else {
Log.d(TAG, "No steps in this recipe");
}
Log.d(TAG, "Image name in database = " + recipe.getImg_url().replace('/', '&'));
Log.d(TAG, "Boolean recipeimage deleted = " + sdUtil.deleteImageFromSD(recipe.getImg_url().replace('/', '&')));
Log.d(TAG, "Deleted rows: " + db.delete("recipes", "id=?", new String[] {Integer.toString(recipe.getId())}));
} else {
Log.d(TAG, "Recipe doesn`t exist");
}
}
private void deleteStepsFromFavoritesByRecipeId(int recipeId) {
Log.d(TAG, "deleteStepsFromFavoritesByRecipeId begin");
db.delete("steps", "recipe_id=?", new String[] { Integer.toString(recipeId)});
}
/*
* public void putRecepy(Recepy recepy) { db.execSQL(INSERT_RECEPY, new
* String[] {Integer.toString(recepy.getId()), recepy.getRecepy(),
* recepy.getAuthor()}); }
*/
public boolean isRecipeExists(int id) {
Cursor c = db.rawQuery(SELECT_RECIPE_BY_ID,
new String[] { Integer.toString(id) });
try {
Log.d(TAG, "isRecipeExists before c.movetoFirst()");
if (c.moveToFirst()) {
if (c != null && c.getCount() > 0) {
Log.d(TAG, "Checking passed");
//Recipe recipe = ModelUtil.getRecipeFromCursor(c);
//Log.d(TAG, "RECIPEExists: " + recipe.toString());
return true;
}
}
} finally {
if (c != null) {
c.close();
}
}
return false;
}
private class DownloadImageStep extends AsyncTask<Object, Void, Object> {
@Override
protected Object doInBackground(Object... o) {
Bitmap outBitmap = null;
try {
sdUtil.saveStepImage((String) o[0]);
} catch (Exception e) {
e.printStackTrace();
}
return outBitmap;
}
}
}
更新： 我发现了我的错误。它在构造函数中。我不必创建 temp_db 并调用 copyData();