Question

我只是复制外部数据库my mydatabase.sqlite并获取所有现有数据，但我在运行时收到此错误

 03-04 00:08:21.621: E/SQLiteLog(16643): (14) cannot open file at line 30217 of [00bb9c9ce4]
    03-04 00:08:21.621: E/SQLiteLog(16643): (14) os_unix.c:30217: (2) open(/data/data/com.examle.sqllightdatabase/databases/mydatabase.sqlite) - 
    03-04 00:08:21.623: E/SQLiteDatabase(16643): Failed to open database '/data/data/com.examle.sqllightdatabase/databases/mydatabase.sqlite'.
    03-04 00:08:21.623: E/SQLiteDatabase(16643): android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14): Could not open database
    03-04 00:08:21.623: E/SQLiteDatabase(16643):    at android.database.sqlite.SQLiteConnection.nativeOpen(Native Method)
    03-04 00:08:21.623: E/SQLiteDatabase(16643):    at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:209)
    03-04 00:08:21.623: E/SQLiteDatabase(16643):    at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:193)
    03-04 00:08:21.623: E/SQLiteDatabase(16643):    at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:463)
    03-04 00:08:21.623: E/SQLiteDatabase(16643):    at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:185)
    03-04 00:08:21.623: E/SQLiteDatabase(16643):    at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:177)
    03-04 00:08:21.623: E/SQLiteDatabase(16643):    at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:829)

sqlHelper.java

package com.examle.sqllightdatabase;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;

public class SqlHelper extends SQLiteOpenHelper {
    private static String DB_PATH = "/data/data/com.examle.sqllightdatabase/databases/";
    private static String DB_NAME = "mydatabase.sqlite";
    private static int VERSION = 1;
    private SQLiteDatabase myDataBase;
    private final Context myContext;
    private static final String TABLE_RECORD = "student";

    public SqlHelper(Context context) {
        super(context, DB_NAME, null, VERSION);
        myContext = context;
        try {
            createDatabase();
        } catch (IOException ioe) {
            throw new Error("Unable to create database");
        }
    }

    public void insertdata(String value) {
        SQLiteDatabase db = getWritableDatabase();
        ContentValues v = new ContentValues();
        v.put("name", value);
        db.insert(TABLE_RECORD, null, v);
        db.close();
    }

    public void createDatabase() throws IOException {
        boolean dbExist = checkDataBase();

        if (dbExist) {
            System.out.println("DB EXIST");
        }

        else {
            this.getReadableDatabase();
            this.close();
            try {
                copyDataBase();
            } catch (IOException e) {
                throw new Error("Error copying database");
            }

        }
    }

    private void copyDataBase() throws IOException {
        InputStream myInput = myContext.getAssets().open(DB_NAME);
        String outFileName = DB_PATH + DB_NAME;
        OutputStream myOutput = new FileOutputStream(outFileName);

        byte[] buffer = new byte[1024];
        int length;
        while ((length = myInput.read(buffer)) > 0) {
            myOutput.write(buffer, 0, length);
        }

        myOutput.flush();
        myOutput.close();
        myInput.close();

    }

    private boolean checkDataBase() {
        SQLiteDatabase checkDB = null;

        try {
            String myPath = DB_PATH + DB_NAME;
            checkDB = SQLiteDatabase.openDatabase(myPath, null,
                    SQLiteDatabase.OPEN_READONLY);
        } catch (SQLiteException e) {
            System.out.println("Database does't exist yet.");
        }

        if (checkDB != null) {
            checkDB.close();
        }

        return checkDB != null ? true : false;

    }

    @Override
    public synchronized void close() {
        if (myDataBase != null)
            myDataBase.close();

        super.close();
    }

    // Getting All records
    public List<String> getAllRecord() {
        List<String> studentList = new ArrayList<String>();
        String selectQuery = "SELECT  * FROM " + TABLE_RECORD;

        SQLiteDatabase db = this.getWritableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null);
        if (cursor.moveToFirst()) {
            do {
                studentList.add(cursor.getString(1));

            } while (cursor.moveToNext());
        }
        db.close();
        return studentList;
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        // TODO Auto-generated method stub

    }

}

Answer 1

这是您找到并实现的旧示例代码，但您缺少一些零碎的东西。您可以轻松地尝试打开不在路径上的数据库文件。尝试在SQLiteDatabase.openDatabase调用之前添加以下两行代码

File file = new File(myPath);    
if (file.exists() && !file.isDirectory())
checkDB = SQLiteDatabase.openDatabase(myPath, null,
                    SQLiteDatabase.OPEN_READONLY);

Answer 2

在github中使用好类///
https://github.com/jgilfelt/android-sqlite-asset-helper
允许您添加现成的数据库。我在我的项目中使用它

复制资产夹资产/数据库/ MyDB.db

中的数据库

public class MyDatabase extends SQLiteAssetHelper {

private static final String DATABASE_NAME = "northwind.db";
private static final int DATABASE_VERSION = 1;

public MyDatabase(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
}

接下来使用简单BD的方法

无法打开数据库

2 个答案: