Question

我该怎么办？谢谢

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

    import android.content.Context;
import android.database.SQLException;
 import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

 Public class DataBaseHelper extends SQLiteOpenHelper
 {
 private static String TAG = "DataBaseHelper"; // Tag just for the LogCat window
//destination path (location) of our database on device
private static String DB_PATH = ""; 
private static String DB_NAME ="finala";// Database name
private SQLiteDatabase mDataBase; 
private final Context mContext;

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() throws IOException
 {
//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.getAssets().open(DB_NAME);
    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();
}

//Open the database, so we can query it
public boolean openDataBase() throws SQLException
{
    String mPath = DB_PATH + DB_NAME;
    //Log.v("mPath", mPath);
     mDataBase = SQLiteDatabase.openDatabase(mPath, null,   SQLiteDatabase.CREATE_IF_NECESSARY);
    //mDataBase = SQLiteDatabase.openDatabase(mPath, null, SQLiteDatabase.NO_LOCALIZED_COLLATORS);
    return mDataBase != null;
}

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

}
  public class DataHelper {

}

错误是：

-The type DatabaseHelper must implement the inherited abstract method SQLiteOpenHelper.onCreate(SQLiteDatabase)
-Breakpoint:DataBaseHelper
-The type DatabaseHelper must implement the inherited abstract method SQLiteOpenHelper.onUpgrade(SQLiteDatabase,int,int)
-Syntax error on token "Public" public expected
-The public type DataBaseHelper must be defined in it's own file.

Answer 1

您必须覆盖onCreate()

中的onUpgrade()和SqliteOpenHelper

因为SqliteOpenHelper是一个抽象类。无论何时扩展抽象类，都需要覆盖（实现）它的抽象方法。

阅读SQLiteHelper class reference。

Answer 2

公共类DataBaseHelper扩展了SQLiteOpenHelper

那不是＆＃34; Public＆＃34;

＆＃34;公共＆＃34;请。

Answer 3

- DatabaseHelper类型必须实现继承的抽象方法SQLiteOpenHelper.onCreate（SQLiteDatabase）

您需要添加

@Override
public void onCreate(SQLiteDatabase db) {
}

使用一些实现来创建数据库模式，以防刚刚创建数据库文件。

-Breakpoint：DataBaseHelper

线上有一个断点。这不是错误，只是一条消息。

- DatabaseHelper类型必须实现继承的抽象方法SQLiteOpenHelper.onUpgrade（SQLiteDatabase，int，int）

您需要添加

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

作为更新数据库架构的方法。你可以先把它留空。

- 令牌“公共”公共预期
上的语法错误

将public与小写p一起使用。

- 公共类型DataBaseHelper必须在它自己的文件中定义。

包级公共类源必须位于与类名匹配的文件中。 DataHelper和DataBaseHelper不匹配;重命名另一个。

总的来说，您似乎正在尝试使用预先填充的数据库。考虑使用android-sqlite-asset-helper库而不是尝试复制您在某处找到的有缺陷的示例。

Eclipse错误数据库连接

3 个答案: