小编GGe*_*GGe的帖子

我需要执行一个查询要从多个表中检索数据,但我对如何一次完成所有操作感到困惑.

Books: _ISBN , BookTitle, Edition, Year, PublisherID, Pages, Rating
Categories: _CategoryID, Category
Categories_Books: _Categories_Category_ID, _Books_ISBN
Publishers: _Publisherid, Publisher
Writers: _WriterID, LastName
Writers_Books: _Writers_WriterID, _Books_ISBN

Categories_Books而Writers_Books在中间表,以帮助我实现很多的表之间的多对多关系.

我需要一个具有多个连接的单个查询来选择:

• 标题,版本,年份,页面,书籍评级
• 类别中的类别
• 出版商的出版商
• 作家姓氏

我讨厌由简单的游标适配器创建的列表:

Cursor c = myDbHelper.rawQ(select);
    startManagingCursor(c);

    // the desired columns to be bound
    String[] columns = new String[] { "Books.BookTitle",
            "Publishers.Publisher" };
    // the XML defined views which the data will be bound to
    int[] to = new int[] { R.id.ISBN_entry, R.id.Title_entry };

    // Getting results into our listview
    try {
        SimpleCursorAdapter mAdapter = new SimpleCursorAdapter(this,
                R.layout.listlayout, c, columns, to);
        this.setListAdapter(mAdapter);
    } catch (Exception e) {

    }

列表涉及的布局是两个简单的文本视图.

我想要做的是创建一个监听器

 @Override
protected void onListItemClick(ListView l, View v, int position, long id) …

很难说只是粘贴我的代码,希望有人会看到我失踪的东西:

Database.Java

package gr.peos;

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.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;

public class Database extends SQLiteOpenHelper{

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

//Name of the Database to be created.
private static String DB_NAME = "BLib";

private SQLiteDatabase myDataBase; 

private final Context myContext;

 /**
 * Constructor
 * Takes and keeps a reference of the passed context in order to access to …