Android：无法打开数据库

ou6hu8tu  于 2023-02-02  发布在  Android
关注(0)|答案(4)|浏览(180)

在我的应用程序中，我正在使用资产文件夹中名为DTUFoodie的现有数据库。打开数据库时，我遇到错误：

08-27 19:36:46.930    5838-5838/com.brainbreaker.dtufoodie E/SQLiteDatabase﹕ Failed to open database '/data/data/com.brainbreaker.dtufoodie/databases/DTUFoodie.db'.

我已经尝试了与此相关的每一个问题的解决方案，仍然无法找到问题。以下是我的数据库助手类的代码。

食品数据库.java

public class FoodieDatabase extends SQLiteAssetHelper {

    private static String DB_PATH = "/data/data/com.brainbreaker.dtufoodie/databases/";
    public String DATABASE_CREATE = "create table "
            + TableData.TableInfo.TABLE_NAME + "("
            + TableData.TableInfo.COLUMN_ID + " INTEGER primary key ,"
            + TableData.TableInfo.COLUMN_hostel + " TEXT not null,"
            + TableData.TableInfo.COLUMN_weekday + " TEXT not null,"
            + TableData.TableInfo.COLUMN_category + " TEXT not null,"
            + TableData.TableInfo.COLUMN_food + " TEXT not null,"
            + TableData.TableInfo.COLUMN_rate + " TEXT not null" + ")";

    private static final int DATABASE_VERSION = 1;
    private SQLiteDatabase dtufoodie;
    Context mycontext;
    private static String DB_NAME = TableData.TableInfo.DATABASE_NAME;

    // Database creation sql statement
    public FoodieDatabase(Context context) {
        super(context, TableData.TableInfo.DATABASE_NAME, null, DATABASE_VERSION);
        this.mycontext = context;
        Log.w("FoodieDatabase", "Database Created");
    }

//    @Override
//    public void onCreate(SQLiteDatabase database) {
//        database.execSQL(DATABASE_CREATE);
//        Log.w(FoodieDatabase.class.getName(),
//                " Table " + TableData.TableInfo.TABLE_NAME + " Successfully created. "
//        );
//    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }

    public void insertvalues(FoodieDatabase fdb, Integer id, String hostel,
                             String weekday, String category, String food, String rate) {
        SQLiteDatabase sdb = fdb.getWritableDatabase();

        ContentValues cv = new ContentValues();
        cv.put(TableData.TableInfo.COLUMN_ID, id);
        cv.put(TableData.TableInfo.COLUMN_hostel, hostel);
        cv.put(TableData.TableInfo.COLUMN_weekday, weekday);
        cv.put(TableData.TableInfo.COLUMN_category, category);
        cv.put(TableData.TableInfo.COLUMN_food, food);
        cv.put(TableData.TableInfo.COLUMN_rate, rate);

        sdb.insert(TableData.TableInfo.TABLE_NAME, null, cv);
    }

    public Cursor retrievevalues(FoodieDatabase fdb) {

        SQLiteDatabase sq = fdb.getReadableDatabase();
        String[] columns = {TableData.TableInfo.COLUMN_ID,
                TableData.TableInfo.COLUMN_hostel,
                TableData.TableInfo.COLUMN_weekday,
                TableData.TableInfo.COLUMN_category,
                TableData.TableInfo.COLUMN_food,
                TableData.TableInfo.COLUMN_rate};
        Cursor CR = sq.query(TableData.TableInfo.TABLE_NAME, columns, null, null, null, null, null);
        return CR;
    }

    /**
     * Creates a empty database on the system and rewrites it with your own database.
     */
    public void createDataBase() throws IOException {

        boolean dbExist = checkDataBase();

        if (dbExist) {
            //do nothing - database already exist
        } else {

            //By calling this method and 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.
            this.getReadableDatabase();

            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 = DB_PATH + DB_NAME;
            checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);

        } catch (SQLiteException e) {

            //database does'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 {

        //Open your local db as the input stream
        InputStream myInput = mycontext.getAssets().open(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);
        }

        //Close the streams
        myOutput.flush();
        myOutput.close();
        myInput.close();

    }

    public void openDataBase() throws SQLException {

        //Open the database
        String myPath = DB_PATH + DB_NAME;
        dtufoodie = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);

    }

    @Override
    public synchronized void close() {

        if (dtufoodie != null)
            dtufoodie.close();

        super.close();

    }

}

使用活动.java

public class Home extends Activity {
    Context context= this;
    String food;
    String hostelname;
    String category;
    String rate;
    String weekday;

    private Toolbar toolbar;
    private DrawerView drawer;
    private ActionBarDrawerToggle drawerToggle;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home);
        DrawerLayout drawerLayout = (DrawerLayout) findViewById(R.id.drawerLayout);
        toolbar = (Toolbar) findViewById(R.id.toolbar);
        drawer = (DrawerView) findViewById(R.id.drawer);
        setSupportActionBar(toolbar);

        // Database Operations
        // FoodieDatabase fdb = new FoodieDatabase(this);
        FoodieDatabase myDbHelper = new FoodieDatabase(this);
        try {
            myDbHelper.createDataBase();
        }
        catch (IOException ioe) {
            throw new Error("Unable to create database");
        }
        try {
            myDbHelper.openDataBase();
        }
        catch(SQLException sqle){
            throw new Error("SQLException: "+sqle);
        }
        Cursor CR = myDbHelper.retrievevalues(myDbHelper);
        CR.moveToFirst();

        do {
            hostelname = "ABH";
            category = CR.getString(1);
            food = CR.getString(2);
            weekday = CR.getString(3);
            rate = CR.getString(4);
            Toast.makeText(Home.this, category, Toast.LENGTH_SHORT).show();
            Toast.makeText(Home.this, weekday, Toast.LENGTH_SHORT).show();

        }
        while(CR.moveToNext());
}}

下面是logcat：

08-27 19:36:46.926    5838-5838/com.brainbreaker.dtufoodie W/FoodieDatabase﹕ Database Created
08-27 19:36:46.927    5838-5838/com.brainbreaker.dtufoodie E/SQLiteLog﹕ (14) cannot open file at line 30191 of [00bb9c9ce4]
08-27 19:36:46.927    5838-5838/com.brainbreaker.dtufoodie E/SQLiteLog﹕ (14) os_unix.c:30191: (2) open(/data/data/com.brainbreaker.dtufoodie/databases/DTUFoodie.db) -
08-27 19:36:46.930    5838-5838/com.brainbreaker.dtufoodie E/SQLiteDatabase﹕ Failed to open database '/data/data/com.brainbreaker.dtufoodie/databases/DTUFoodie.db'.
    android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14): Could not open database
            at android.database.sqlite.SQLiteConnection.nativeOpen(Native Method)
            at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:209)
            at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:193)
            at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:463)
            at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:185)
            at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:177)
            at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:804)
            at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:789)
            at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:694)
            at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:669)
            at com.brainbreaker.dtufoodie.database.FoodieDatabase.checkDataBase(FoodieDatabase.java:128)
            at com.brainbreaker.dtufoodie.database.FoodieDatabase.createDataBase(FoodieDatabase.java:94)
            at com.brainbreaker.dtufoodie.Home.onCreate(Home.java:78)
            at android.app.Activity.performCreate(Activity.java:5248)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1110)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2162)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2257)
            at android.app.ActivityThread.access$800(ActivityThread.java:139)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5086)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
            at dalvik.system.NativeStart.main(Native Method)
08-27 19:36:46.930    5838-5838/com.brainbreaker.dtufoodie W/SQLiteAssetHelper﹕ copying database from assets...
08-27 19:36:46.933    5838-5838/com.brainbreaker.dtufoodie E/SQLiteAssetHelper﹕ Couldn't open DTUFoodie.db for writing (will try read-only):
    com.readystatesoftware.sqliteasset.SQLiteAssetHelper$SQLiteAssetException: Missing databases/DTUFoodie.db file (or .zip, .gz archive) in assets, or target folder not writable
            at android.content.res.AssetManager.openAsset(Native Method)
            at android.content.res.AssetManager.open(AssetManager.java:316)
            at android.content.res.AssetManager.open(AssetManager.java:290)
            at com.readystatesoftware.sqliteasset.SQLiteAssetHelper.copyDatabaseFromAssets(SQLiteAssetHelper.java:436)
            at com.readystatesoftware.sqliteasset.SQLiteAssetHelper.createOrOpenDatabase(SQLiteAssetHelper.java:400)
            at com.readystatesoftware.sqliteasset.SQLiteAssetHelper.getWritableDatabase(SQLiteAssetHelper.java:176)
            at com.readystatesoftware.sqliteasset.SQLiteAssetHelper.getReadableDatabase(SQLiteAssetHelper.java:254)
            at com.brainbreaker.dtufoodie.database.FoodieDatabase.createDataBase(FoodieDatabase.java:102)
            at com.brainbreaker.dtufoodie.Home.onCreate(Home.java:78)
            at android.app.Activity.performCreate(Activity.java:5248)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1110)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2162)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2257)
            at android.app.ActivityThread.access$800(ActivityThread.java:139)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5086)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
            at dalvik.system.NativeStart.main(Native Method)
08-27 19:36:46.933    5838-5838/com.brainbreaker.dtufoodie E/SQLiteLog﹕ (14) cannot open file at line 30191 of [00bb9c9ce4]
08-27 19:36:46.933    5838-5838/com.brainbreaker.dtufoodie E/SQLiteLog﹕ (14) os_unix.c:30191: (2) open(/data/data/com.brainbreaker.dtufoodie/databases/DTUFoodie.db) -
08-27 19:36:46.936    5838-5838/com.brainbreaker.dtufoodie E/SQLiteDatabase﹕ Failed to open database '/data/data/com.brainbreaker.dtufoodie/databases/DTUFoodie.db'.

任何帮助都很感激。先谢了。

android

4条答案

按热度按时间
7xllpg7q

7xllpg7q1#

我也遇到了同样的问题。对我来说，解决办法是把数据库放在正确的文件夹中。
将数据库文件放在/src/main/assets/databases/您的数据库文件. db中
来源：Problems when using existing sqlite database

赞(0）分享  回复(0）举报  2023-02-02
bf1o4zei

bf1o4zei2#

意图：“SQLite数据库.OPEN_READWRITE”

public void openDataBase(){
    //Abre la base de datos
    try {
        createDataBase();
    } catch (IOException e) {
        Log.e("SQLiteError","Error al abrir base de datos: \n"+e.getMessage());
    }
    String myPatch = DB_PATH + DB_NAME;
    categoryDB = SQLiteDatabase.openDatabase(myPatch, null, SQLiteDatabase.OPEN_READWRITE);
}
赞(0）分享  回复(0）举报  2023-02-02
6ju8rftf

6ju8rftf3#

这可能是因为谷歌添加了从不允许功能从Android S. app_data无法从具有“mlstrustedobject”. mls（多级安全）信任对象的域访问。
删除此“对象”。
参考链路https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/selinux_users_and_administrators_guide/mls

赞(0）分享  回复(0）举报  2023-02-02
vybvopom

vybvopom4#

这是文件的问题（.db文件），我解决了这个问题，压缩.db文件到.zip文件在一个经典的（最原始的）方式。

赞(0）分享  回复(0）举报  2023-02-02
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