我有一个问题。“强制停止”后，我的数据库变为空。最初我打开空数据库，然后我正在添加一些数据。然后我在数据库中看到它们，它们可以在程序中看到。但是，如果我重新启动手机或“强制停止”应用程序 - 一切都从头开始。
这是我的DataBaseFactory代码：
package com.st.nyam.factories;
公共类数据库工厂 {
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 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 (?,?,?,?,?,?) ";
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) {
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()
});
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,"Recipe already added");
}
}
public 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 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;
}
}
}