android - 如何在android应用程序的数据库中存储视频文件

Question

在我的应用程序中，我希望数据库包含一些视频。
是否可以将视频存储在数据库中？
如果可能的话给我示例链接。

Answer 1

将视频文件存储在数据库中是不好的做法，不是一种方便的方法。因此将您的视频文件存储在External Storage或Internal Storage中，并将这些视频文件的路径存储在数据库中。因此，您可以从数据库中快速访问您的数据。它对您的应用程序性能也有好处。

Answer 2

package database;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Environment;
import android.util.Log;

public class DataBaseHelper extends SQLiteOpenHelper {

    private static String DB_NAME = "your_db_name.sqlite";
    private SQLiteDatabase myDataBase;
    private final Context myContext;
    private String DB_PATH;

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

        super(context, DB_NAME, null, 1);
        this.myContext = context;
        this.DB_PATH = Environment.getDataDirectory() + "/data/"
                + myContext.getPackageName() + "/databases/";
    }

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

        boolean dbExist = checkDataBase();
        SQLiteDatabase db_Read = null;
        if (dbExist) {
            Log.i("DataBase", "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.
            db_Read = this.getReadableDatabase();
            db_Read.close();
            try {
                copyDataBase();
                Log.i("DataBase", "Copy DataBase");

            } catch (Exception e) {
                // TODO: handle exception
                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
     */
public boolean checkDataBase() {

        SQLiteDatabase checkDB = null;

        try {
            String myPath = DB_PATH + DB_NAME;
            // this path value is coming correct?
            checkDB = SQLiteDatabase.openDatabase(myPath, null,
                    SQLiteDatabase.OPEN_READWRITE);

        } 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.
     * 
     * @throws IOException
     * */
    private void copyDataBase() {

        // Open your local db as the input stream

        try {
            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();

        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

    public void openDataBase() throws SQLException {

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

    }

    public void deleteEntry(String table_name ,String whereclause ,String[] field_value) throws SQLException {

        // delete the database
        myDataBase.delete(table_name, whereclause, field_value);

    }

    public void insertEntry(String table_name ,ContentValues field_value) throws SQLException {

        // insert the database
        myDataBase.insert(table_name, null, field_value);

    }

    public void updateEntry(String table_name ,ContentValues field_value,String whereClause,String[] whereArgs) throws SQLException {

        // insert the database
        myDataBase.update(table_name, field_value, whereClause, whereArgs);

    }

    @Override
    public void close() {

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

        super.close();

    }

    public Cursor fetchDataFromDataBase(String query) {
        Cursor cursor = null;
        if (myDataBase != null) {
            cursor = myDataBase.rawQuery(query, null);
        }
        return cursor;

    }

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

    }

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

    }

}

• 项目清单

  // and call from your application level class when your application launche first
  // then use your database by using sq-lite query
  
       myDbHelper = new DataBaseHelper(this);
  
  
  try {
      // calling from here to creat databases from assets
      myDbHelper.createDataBase();
  } catch (IOException ioe) {
  
      throw new Error("Unable to create database");
  
  }
  

• 项目清单

        // just use query like that
       // calling from here to open databases from assets
  DataBaseHelper myDbHelper = new DataBaseHelper(m_context);
  if (myDbHelper != null) {
      myDbHelper.openDataBase();
  }
  
  Cursor cursor = myDbHelper.fetchDataFromDataBase(squery);