android : 从 assets 文件夹 (sqlite db) 导出数据并将其导入应用程序的数据库

Question

更新

我找到了这个链接

http://www.reigndesign.com/blog/using-your-own-sqlite-database-in-android-applications/

谁能解释我将如何使用这个来编写更新/插入语句

___________________________________________________________________________

问题

我正在尝试创建一种方法，我可以将存储在 sqllite 数据库中的数据复制到我的应用程序的数据库中。结构类似。我只是不想一一插入行。

我正在寻找一种方法，通过该方法我可以将存储在资产文件夹或外部存储中的预先输入的数据复制到我的应用程序数据库中。

我在我的应用程序中填写数据时遇到问题。我不想以编程方式为每一行和每一列编写 5000 个插入语句。

谁能推荐一个方法。我是android新手，所以请详细解释或提供链接。

我的数据库助手类

import java.util.ArrayList;
import java.util.List;

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

public class DBHelper extends SQLiteOpenHelper {
    public  SQLiteDatabase db1;


    // Static Final Variable database meta information

    static final String DATABASE = "assesmenttool.db";
    static final int DATABASE_VERSION = 1;

    //Table Student Details
    static final String TABLEStudent = "StudentDetails";
    static final String S_ID = "_id";
    static final String SchoolID = "SchoolID";
    static final String SchoolName = "schoolname";
    static final String StudentFirstName = "StudentFirstName";
    static final String StudentLastName ="StudentLastName";
    static final String StudentClassLevel ="StudentClassLevel";
    static final String RollNo="RollNo";
    static final String TestDate ="TestDate";

     //Table Response Details   
    static final String TABLEResponse = "TableResponse";
    static final String R_ID = "_id";
    static final String StudentID = "StudentID";
    static final String R_QuestionID = "QuestionID";
    static final String QuestOptionID = "QuestOptionID";

    //Table Question Master
    static final String TableQuestionMaster = "TableQuestionMaster";
    static final String Q_ID= "_id";
    static final String Module_ID = "Module_ID";
    static final String SubModule_ID = "SubModule_ID";
    static final String SubModuleQuestion_ID ="SubModuleQuestion_ID";
    static final String Question_ID= "Question_ID"; 
    static final String Title = "Title";
    static final String Module = "Module";
    static final String TitleDescription = "TitleDescription";
    static final String QuestionText = "QuestionText";
    static final String QuestionImage = "QuestionImage";
    static final String QuestionTemplate = "QuestionTemplate";
    static final String CorrectOptionID = "CorrectOptionID";

    //Table Template Master
    static final String TableTemplateMaster = "TemplateMaster";
    static final String T_ID= "_id";
    static final String Template_ID= "Template_ID"; 
    static final String Name = "Name";
    static final String Description = "Description";

    //Table Question Option 
    static final String TableQuestionOption = "TableQuestionOption";
    static final String TQP_ID= "_id";
    static final String TQP_QuestionID = "QuestionID";
    static final String OptionText = "OptionText";

    //Table Class Master
    static final String TableClassMaster = "TableClassMaster";
    static final String Class_ID= "_id";
    static final String Class = "class";


    // Override constructor
    public DBHelper(Context context) {
        super(context, DATABASE, null, DATABASE_VERSION);

    }


    // Override onCreate method
    @Override
    public void onCreate(SQLiteDatabase db) {


        //Create Table Student Details
        db.execSQL("CREATE TABLE " + TABLEStudent + " ( " + S_ID
                + " INTEGER PRIMARY KEY AUTOINCREMENT, " + SchoolID + " text, "
                + SchoolName + " text, " + StudentFirstName + " text, "  + StudentLastName + " text, " + RollNo + " text," + TestDate + " text," + StudentClassLevel + " text)");


        //Create Table Response Details     
        db.execSQL("CREATE TABLE " + TABLEResponse + " ( " + R_ID
                + " INTEGER PRIMARY KEY AUTOINCREMENT, " + StudentID + " text, "
                + R_QuestionID + " text, " + QuestOptionID + " text)");


        //Create Table Question Master
        db.execSQL("CREATE TABLE " + TableQuestionMaster + " ( " + Q_ID
                + " INTEGER PRIMARY KEY AUTOINCREMENT, " +  Question_ID + " text, " +  Module_ID + " text, " +  SubModule_ID + " text, " +  SubModuleQuestion_ID + " text,  " + Title + " text, "  +  Module + " text," 
                + TitleDescription + " text, " + QuestionText + " text, "  + QuestionImage + " text, " + QuestionTemplate + " text," + CorrectOptionID + " text)");


        //Create Table Template Master
        db.execSQL("CREATE TABLE " + TableTemplateMaster + " ( " + T_ID
                + " INTEGER PRIMARY KEY AUTOINCREMENT, " + Name + " text, "
                + Description + " text)");


        //Create Table Question Option  
        db.execSQL("CREATE TABLE " + TableQuestionOption + " ( " + TQP_ID
                + " INTEGER PRIMARY KEY AUTOINCREMENT, " + TQP_QuestionID + " text, "
                + OptionText + " text)");   

        //Create Table Class Master 
        db.execSQL("CREATE TABLE " + TableClassMaster + " ( " + Class_ID
                + " INTEGER PRIMARY KEY AUTOINCREMENT, " + Class + " text)");   

    }

       public List<String> getAllClasses(){
            List<String> labels = new ArrayList<String>();

            // Select All Query
            String selectQuery = "SELECT  * FROM " + TableClassMaster;

            SQLiteDatabase db = this.getReadableDatabase();
            Cursor cursor = db.rawQuery(selectQuery, null);

            // looping through all rows and adding to list
            if (cursor.moveToFirst()) {
                do {
                    labels.add(cursor.getString(1));
                } while (cursor.moveToNext());
            }

            // closing connection
            cursor.close();
            db.close();

            // returning lables
            return labels;
        }

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

        // Drop old version table
        db.execSQL("Drop table " + TABLEStudent);
        db.execSQL("Drop table " + TABLEResponse);
        db.execSQL("Drop table " + TableQuestionMaster);
        db.execSQL("Drop table " + TableTemplateMaster);
        db.execSQL("Drop table " + TableQuestionOption);
        db.execSQL("Drop table " + TableClassMaster);
        // Create New Version table
        onCreate(db);
    }




}

我在 stackoverflow 上找到的 SQLLITE 复制类

如何将这两者混合在一起。我如何同步这两个 sqllite 表。 ?

  private static final String DB_NAME = "asset.db";

    private Context context;

    public AssetDatabaseOpenHelper(Context context) {
        this.context = context;
    }

    public SQLiteDatabase openDatabase() {
        File dbFile = context.getDatabasePath(DB_NAME);

        if (!dbFile.exists()) {
            try {
                copyDatabase(dbFile);
            } catch (IOException e) {
                throw new RuntimeException("Error creating source database", e);
            }
        }

        return SQLiteDatabase.openDatabase(dbFile.getPath(), null, SQLiteDatabase.OPEN_READONLY);
    }

    private void copyDatabase(File dbFile) throws IOException {
        InputStream is = context.getAssets().open(DB_NAME);
        OutputStream os = new FileOutputStream(dbFile);

        byte[] buffer = new byte[1024];
        while (is.read(buffer) > 0) {
            os.write(buffer);
        }

        os.flush();
        os.close();
        is.close();
    }

}

Answer 1

这将解决我的答案..

只需使用 sqlliteOPenHelper 类的帮助..

第一步

添加 copyDataBase() 函数..

第二步

像这样在你的 MainActivity 中启动它

helper = new DBHelper(this);

        try {

            helper.createDataBase();

    } catch (IOException ioe) {

        throw new Error("Unable to create database");

    }

    try {

        helper.openDataBase();

    }catch(SQLException sqle){

        throw sqle;

    }

你的 DBHelper 类看起来像

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.Context;
import android.database.Cursor;
import android.database.MatrixCursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

public class DBHelper extends SQLiteOpenHelper {
    public  SQLiteDatabase db1;


    // Static Final Variable database meta information

    static final String DATABASE = "assesmenttool.db";
    static final int DATABASE_VERSION = 1;

    //Table Student Details
    static final String TABLEStudent = "StudentDetails";
    static final String S_ID = "_id";
    static final String SchoolID = "SchoolID";
    static final String SchoolName = "schoolname";
    static final String StudentFirstName = "StudentFirstName";
    static final String StudentLastName ="StudentLastName";
    static final String StudentClassLevel ="StudentClassLevel";
    static final String RollNo="RollNo";
    static final String TestDate ="TestDate";

     //Table Response Details   
    static final String TABLEResponse = "TableResponse";
    static final String R_ID = "_id";
    static final String StudentID = "StudentID";
    static final String R_QuestionID = "QuestionID";
    static final String QuestOptionID = "QuestOptionID";

    //Table Question Master
    static final String TableQuestionMaster = "TableQuestionMaster";
    static final String Q_ID= "_id";
    static final String Module_ID = "Module_ID";
    static final String SubModule_ID = "SubModule_ID";
    static final String SubModuleQuestion_ID ="SubModuleQuestion_ID";
    static final String Question_ID= "Question_ID"; 
    static final String Title = "Title";
    static final String Module = "Module";
    static final String TitleDescription = "TitleDescription";
    static final String QuestionText = "QuestionText";
    static final String QuestionImage = "QuestionImage";
    static final String QuestionTemplate = "QuestionTemplate";
    static final String CorrectOptionID = "CorrectOptionID";

    //Table Template Master
    static final String TableTemplateMaster = "TemplateMaster";
    static final String T_ID= "_id";
    static final String Template_ID= "Template_ID"; 
    static final String Name = "Name";
    static final String Description = "Description";

    //Table Question Option 
    static final String TableQuestionOption = "TableQuestionOption";
    static final String TQP_ID= "_id";
    static final String TQP_QuestionID = "QuestionID";
    static final String TQP_OptionID = "TQP_OptionID";
    static final String OptionText = "OptionText";

    //Table Class Master
    static final String TableClassMaster = "TableClassMaster";
    static final String Class_ID= "_id";
    static final String Class = "class";




       private static String DB_PATH = "/data/data/com.cldonline.assesmenttool/databases/";

        private static String DB_NAME = "assesmenttool.db";

        private SQLiteDatabase myDataBase; 

        private final Context myContext;

        /**
         * Constructor
         * Takes and keeps a reference of the passed context in order to access to the application assets and resources.
         * @param context
         */
        public DBHelper(Context context) {

            super(context, DB_NAME, null, 1);
            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();

            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();

        }





        // Override onCreate method
        @Override
        public void onCreate(SQLiteDatabase db) {



        }

           public List<String> getAllClasses(){
                List<String> labels = new ArrayList<String>();

                // Select All Query
                String selectQuery = "SELECT  * FROM " + TableClassMaster;

                SQLiteDatabase db = this.getReadableDatabase();
                Cursor cursor = db.rawQuery(selectQuery, null);

                // looping through all rows and adding to list
                if (cursor.moveToFirst()) {
                    do {
                        labels.add(cursor.getString(1));
                    } while (cursor.moveToNext());
                }

                // closing connection
                cursor.close();
                db.close();

                // returning lables
                return labels;
            }

           public List<String> getAllOptions(String Qid){
                List<String> options = new ArrayList<String>();

                // Select All Query
                String selectQuery = "SELECT * FROM " + TableQuestionOption +" "+"where QuestionID ='"+Qid+"'";

                SQLiteDatabase db = this.getReadableDatabase();
                Cursor cursor = db.rawQuery(selectQuery, null);

                // looping through all rows and adding to list
                if (cursor.moveToFirst()) {
                    do {
                        options.add(cursor.getString(2));
                    } while (cursor.moveToNext());
                }

                // closing connection
                cursor.close();
                db.close();

                // returning lables
                return options;
            }

           public void openDataBase() throws SQLException{

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

            }

            @Override
            public synchronized void close() {

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

                    super.close();

            }

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


        }

        public ArrayList<Cursor> getData(String Query){
            //get writable database
            SQLiteDatabase sqlDB = this.getWritableDatabase();
            String[] columns = new String[] { "mesage" };
            //an array list of cursor to save two cursors one has results from the query 
            //other cursor stores error message if any errors are triggered
            ArrayList<Cursor> alc = new ArrayList<Cursor>(2);
            MatrixCursor Cursor2= new MatrixCursor(columns);
            alc.add(null);
            alc.add(null);


            try{
                String maxQuery = Query ;
                //execute the query results will be save in Cursor c
                Cursor c = sqlDB.rawQuery(maxQuery, null);


                //add value to cursor2
                Cursor2.addRow(new Object[] { "Success" });

                alc.set(1,Cursor2);
                if (null != c && c.getCount() > 0) {


                    alc.set(0,c);
                    c.moveToFirst();

                    return alc ;
                }
                return alc;
            } catch(SQLException sqlEx){
                Log.d("printing exception", sqlEx.getMessage());
                //if any exceptions are triggered save the error message to cursor an return the arraylist
                Cursor2.addRow(new Object[] { ""+sqlEx.getMessage() });
                alc.set(1,Cursor2);
                return alc;
            } catch(Exception ex){

                Log.d("printing exception", ex.getMessage());

                //if any exceptions are triggered save the error message to cursor an return the arraylist
                Cursor2.addRow(new Object[] { ""+ex.getMessage() });
                alc.set(1,Cursor2);
                return alc;
            }


        }




}

Answer 2

检查this。给出位于项目资产文件夹中的数据库路径。您可以在SQLiteOpenHelper的帮助下复制整个数据库。

public class PlanDetailsSQLiteOpenHelper extends SQLiteOpenHelper {
    private static final String TAG = "SQLiteOpenHelper";

    private final Context context;
    private static final int DATABASE_VERSION = 1;
    private static final String DATABASE_NAME = "my_custom_db";

    private boolean createDb = false, upgradeDb = false;

    public PlanDetailsSQLiteOpenHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        this.context = context;
    }

    /**
     * Copy packaged database from assets folder to the database created in the
     * application package context.
     *
     * @param db
     *            The target database in the application package context.
     */
    private void copyDatabaseFromAssets(SQLiteDatabase db) {
        Log.i(TAG, "copyDatabase");
        InputStream myInput = null;
        OutputStream myOutput = null;
        try {
            // Open db packaged as asset as the input stream
            myInput =context.getAssets().open("your_database_path");

            // Open the db in the application package context:
            myOutput = new FileOutputStream(db.getPath());

            // Transfer db file contents:
            byte[] buffer = new byte[1024];
            int length;
            while ((length = myInput.read(buffer)) > 0) {
                myOutput.write(buffer, 0, length);
            }
            myOutput.flush();

            // Set the version of the copied database to the current
            // version:

            SQLiteDatabase copiedDb = context.openOrCreateDatabase(
                    DATABASE_NAME, 0, null);
            copiedDb.execSQL("PRAGMA user_version = " + DATABASE_VERSION);
           // copiedDb.close();


        } catch (IOException e) {
            e.printStackTrace();
            throw new Error(TAG + " Error copying database");
        } finally {
            // Close the streams
            try {
                if (myOutput != null) {
                    myOutput.close();
                }
                if (myInput != null) {
                    myInput.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
                throw new Error(TAG + " Error closing streams");
            }
        }
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        Log.i(TAG, "onCreate db");
        createDb = true;
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        Log.i(TAG, "onUpgrade db");
        upgradeDb = true;

    }

    @Override
    public void onOpen(SQLiteDatabase db) {
        Log.i(TAG, "onOpen db");
        if (createDb) {// The db in the application package
            // context is being created.
            // So copy the contents from the db
            // file packaged in the assets
            // folder:
            createDb = false;
            copyDatabaseFromAssets(db);

        }
        if (upgradeDb) {// The db in the application package
            // context is being upgraded from a lower to a higher version.
            upgradeDb = false;
            // Your db upgrade logic here:

        }

    }
}

Answer 3

我用同样的方法。我有一个帮助类：

public class DatabaseImport {
private static final String TAG = "DataAdapter";

private final DataBaseHelper mDbHelper;

public DatabaseImport(Context context) {
    Context mContext = context;
    mDbHelper = new DataBaseHelper(mContext);
}

public void createDatabase() {
    try {
        mDbHelper.createDataBase();
    } catch (Exception mIOException) {
        Log.e(TAG, mIOException.toString() + "  UnableToCreateDatabase");
        throw new Error("UnableToCreateDatabase");
    }
}

我在我的 DBHelper 类中调用它。

class DataBaseHelper extends SQLiteOpenHelper {

//The Android's default system path of your application database.
private static String DB_PATH = "/data/data/yourpackagename/databases/";

private static final String DB_NAME = "databasename";

private static final String TAG = "DataBaseHelper"; // Tag just for the LogCat window
//destination path (location) of our database on device
private final Context mContext;
private SQLiteDatabase mDataBase;

public DataBaseHelper(Context context) {
    super(context, DB_NAME, null, 1);// 1? its Database Version
    if (android.os.Build.VERSION.SDK_INT >= 17) {
        DB_PATH = context.getApplicationInfo().dataDir + "/databases/";
    } else {
        DB_PATH = "/data/data/" + context.getPackageName() + "/databases/";
    }
    this.mContext = context;
}

public void createDataBase() {
    //If database not exists copy it from the assets

    boolean mDataBaseExist = checkDataBase();
    if (!mDataBaseExist) {
        this.getReadableDatabase();
        this.close();
        try {
            //Copy the database from assests
            copyDataBase();
            Log.e(TAG, "createDatabase database created");
        } catch (IOException mIOException) {
            throw new Error("ErrorCopyingDataBase");
        }
    }
}

//Check that the database exists here: /data/data/your package/databases/Da Name
private boolean checkDataBase() {
    File dbFile = new File(DB_PATH + DB_NAME);
    //Log.v("dbFile", dbFile + "   "+ dbFile.exists());
    return dbFile.exists();
}

//Copy the database from assets
private void copyDataBase() throws IOException {
    InputStream mInput = mContext.getResources().openRawResource(R.raw.kindersporttabelle);
    String outFileName = DB_PATH + DB_NAME;
    OutputStream mOutput = new FileOutputStream(outFileName);
    byte[] mBuffer = new byte[1024];
    int mLength;
    while ((mLength = mInput.read(mBuffer)) > 0) {
        mOutput.write(mBuffer, 0, mLength);
    }
    mOutput.flush();
    mOutput.close();
    mInput.close();
}

@Override
public synchronized void close() {
    if (mDataBase != null)
        mDataBase.close();
    super.close();
}

@Override
public void onCreate(SQLiteDatabase db) {

}

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

}

}

可以使用普通的 DataBaseHandler 访问和使用您的数据库：

public class DatabaseHandler extends SQLiteOpenHelper {

private static final int DATABASE_VERSION = 1;
//databasename
private static final String DATABASE_NAME = "databasename";
//table names
[...]
//game name column names

[....]

private static Context myContext;

private static DatabaseHandler mInstance = null;

/**
 * Constructor
 * Takes and keeps a reference of the passed context in order to access to the application assets and resources.
 */
private DatabaseHandler(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
}

public static DatabaseHandler getInstance(Context context) {
    if (mInstance == null) {
        mInstance = new DatabaseHandler(context.getApplicationContext());
    }
    myContext = context;
    return mInstance;
}

@Override
public void onCreate(SQLiteDatabase db) {

    Intent intent = new Intent(myContext, MainActivity.class);
    myContext.startActivity(intent);

    DatabaseImport mDbHelper = new DatabaseImport(myContext);
    try {
        mDbHelper.createDatabase();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("DROP TABLE IF EXISTS " + tablename);
    myContext.deleteDatabase(DATABASE_NAME);

    onCreate(db);
}

}

您只需要调整正确的类名。这应该有效。祝你好运。