如何將數據庫從資產文件夾複製到數據庫文件夾？

Question

我設計了一個數據庫與SQL精簡版專家的專業，並將其複製到文件夾的資產，但我不能把它複製到數據庫文件夾

我不想用我的代碼，因爲它不工作...

任何人都可以分享他的代碼嗎？

對不起我的英語這麼差

Answer 1

我的問題解決了:)

大家，有從資源文件夾到數據庫文件夾複製數據庫的問題，可以使用下面的代碼

package com.example.zedaastan; 

import java.io.File; 
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.SQLiteOpenHelper; 

public class database extends SQLiteOpenHelper { 

private static SQLiteDatabase mydb; 
private static final int DATABASE_VERSION = 1; 
private static final String DB_NAME = "database"; 
private static final String DB_PATH = "/databases/"; 
static Context ctx; 


@Override 
public void onCreate(SQLiteDatabase arg0) { 
    // TODO Auto-generated method stub 

} 

public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) { 
    // TODO Auto-generated method stub 

} 



public database(Context context) { 
    super(context, DB_NAME, null, DATABASE_VERSION); 
    ctx = context; 
} 

public void CopyDataBaseFromAsset() throws IOException{ 

    InputStream myInput = ctx.getAssets().open(DB_NAME); 
// Path to the just created empty db 
String outFileName = getDatabasePath(); 
// if the path doesn't exist first, create it 
File f = new File(ctx.getApplicationInfo().dataDir + DB_PATH); 
    if (!f.exists()) 
     f.mkdir(); 
// 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 open(){ 
File dbFile = ctx.getDatabasePath(DB_NAME); 
} 

public void close(){ 
    mydb.close(); 
} 

private static String getDatabasePath() { 

    return ctx.getApplicationInfo().dataDir + DB_PATH 
      + DB_NAME; 
} 

public SQLiteDatabase openDataBase() throws SQLException{ 
    File dbFile = ctx.getDatabasePath(DB_NAME); 
    if (!dbFile.exists()) { 
     try { 
      CopyDataBaseFromAsset(); 
      System.out.println("Copying sucess from Assets folder"); 
     } catch (IOException e) { 
      throw new RuntimeException("Error creating source database", e); 
     } 
    } 

    return SQLiteDatabase.openDatabase(dbFile.getPath(), null,   SQLiteDatabase.NO_LOCALIZED_COLLATORS | 
      SQLiteDatabase.CREATE_IF_NECESSARY); 
}