要想操作数据库，首先我们要获取一个事务SQLiteDatabase

    public SQLiteDatabase getWritableDatabase() {
        synchronized (this) {
            return getDatabaseLocked(true);
        }
    }

  private SQLiteDatabase getDatabaseLocked(boolean writable) {

//    	...省略
    	
        SQLiteDatabase db = mDatabase;

            if (db != null) {
                if (writable && db.isReadOnly()) {
                    db.reopenReadWrite();
                }
            } else if (mName == null) {
                db = SQLiteDatabase.create(null);
            } else {
                try {
                    if (DEBUG_STRICT_READONLY && !writable) {
                        final String path = mContext.getDatabasePath(mName).getPath();
                        db = SQLiteDatabase.openDatabase(path, mFactory,
                                SQLiteDatabase.OPEN_READONLY, mErrorHandler);
                    } else {
                        db = mContext.openOrCreateDatabase(mName, mEnableWriteAheadLogging ?
                                Context.MODE_ENABLE_WRITE_AHEAD_LOGGING : 0,
                                mFactory, mErrorHandler);
                    }
//                	...省略

    }

    public SQLiteOpenHelper(Context context, String name, CursorFactory factory, int version,
            DatabaseErrorHandler errorHandler) {
        if (version < 1) throw new IllegalArgumentException("Version must be >= 1, was " + version);

        mContext = context;
        mName = name;
        mFactory = factory;
        mNewVersion = version;
        mErrorHandler = errorHandler;
    }

那就好办了！

public SQLiteOpenHelperImp(Context context) {
		super(context, getMyDatabaseName(context)， null, DATABASE_VERSION);
	}

 private static String getMyDatabaseName(Context context){  
	       String databasename = DATABASE_NAME;  
	       boolean isSdcardEnable =false;  
//	       String state =Environment.getExternalStorageState();  
	       boolean state =Environment.isExternalStorageRemovable();  
	       if(state){//SDCard是否插入  
	          isSdcardEnable = true;  
	       }  
	       String dbPath = "";  
	       if(isSdcardEnable){  
	           dbPath =Environment.getExternalStorageDirectory().getPath() +"/database/";  
	       }else{//未插入SDCard，建在内存中  
	           dbPath =context.getFilesDir().getPath() + "/database/";  
	       }  
	       File dbp = new File(dbPath);  
	       if(!dbp.exists()){  
	          dbp.mkdirs();  
	       }  
	       databasename = dbPath +DATABASE_NAME;  
	       return databasename;  
	    }