UITableView中來自SQLite的iOS NSDictionaries的NSArray

Question

在過去的兩天里，我一直在為這個問題而苦苦掙扎，但我似乎還不太清楚。 我有一個具有以下結構的SQlite數據庫。

這是List和List_Items之間的一對多關系

我訪問數據庫並創建一個對象，然后將該對象添加到NSDictionary中，該對象又添加到NSArray中。 我執行兩次，一次用於List表，一次用於List_Items。 然后，我使用列表數組來計數我的表視圖行的列表數，然后將它們添加到表視圖中。

問題出在我了解方法時

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath 

我似乎無法弄清楚如何匹配Lists和List_Items中的記錄，以在向下鑽取的表格視圖中顯示與該列表有關的List Items。

具體的代碼示例可能會有所幫助，因為我現在對此很不了解:(

這是我當前的Writersblock擁有的相關代碼。

 //#******************************************************#

//               *******Start Database*******

//#******************************************************#

-(void)checkAndCreateDatabase
{
    // Check if the SQL database has already been saved to the users phone, if not then copy it over
    BOOL success;

    // Create a FileManager object, we will use this to check the status
    // of the database and to copy it over if required
    NSFileManager *fileManager = [NSFileManager defaultManager];

    // Check if the database has already been created in the users filesystem
    success = [fileManager fileExistsAtPath:databasePath];

    // If the database already exists then return without doing anything
    if(success) return;

    // If not then proceed to copy the database from the application to the users filesystem

    // Get the path to the database in the application package
    NSString *databasePathFromApp = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:databaseName];

    // Copy the database from the package to the users filesystem
    [fileManager copyItemAtPath:databasePathFromApp toPath:databasePath error:nil];
}

-(void)readItemsFromDatabase 
{
    // Setup the database object
    sqlite3 *database;

    // Init the Items Array
    items = [[NSMutableArray alloc] init];
    lists = [[NSMutableArray alloc] init];

    //---------------### SELECT THE LISTS #####---------------//

    // Open the database from the users filessytem
    if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) 
    {
        NSLog(@"SQL Opened");
        // Setup the SQL Statement and compile it for faster access
        const char *sqlStatement = "SELECT * from List";
        sqlite3_stmt *compiledStatement;
        if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) {
            // Loop through the results and add them to the array
            while(sqlite3_step(compiledStatement) == SQLITE_ROW) {
                // Read the data from the result row
                NSString *aListName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 1)];
                NSString *aUserID = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 2)];
                NSString *aListID = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 3)];

                NSLog(@"SQL Compiled");

                // Create a new list object with the data from the database
                List *list = [[List alloc] initWithlistName:(NSString *)aListName userID:(NSString *)aUserID listID:(NSString *)aListID];

                listNames = [NSDictionary dictionaryWithObjectsAndKeys:list.listName,@"listName",list.listID,@"listID",list.listID,@"listID",nil];

                // Add the Shopping object to the list Array
                [lists addObject:listNames];

            }
        }

        else { NSLog(@"Database Not Found");}

        // Release the compiled statement from memory
        sqlite3_finalize(compiledStatement);
    }
    sqlite3_close(database);

        //---------------### SELECT THE LIST_ITEMS #####---------------//

        if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) 
        {
            NSLog(@"SQL Opened");
            // Setup the SQL Statement and compile it for faster access
            const char *sqlStatement = "SELECT * from List_Items";
            sqlite3_stmt *compiledStatement;
            if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) {
                // Loop through the results and add them to the array
                while(sqlite3_step(compiledStatement) == SQLITE_ROW) {
                    // Read the data from the result row

                    NSString *aBrandName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 1)];
                    NSString *aItemName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 2)];
                    NSString *aItemQuantity = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 4)];
                    NSString *aImageUrl = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 5)];
                    NSString *aListID = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 6)];

                    NSLog(@"SQL Compiled");

                    // Create a new items object with the data from the database
                    Shopping *shopping = [[Shopping alloc] initWithlistID:(NSString *)aListID brandName:(NSString *)aBrandName itemName:(NSString *)aItemName itemQuantity:(NSString *)aItemQuantity imageURL:(NSString *)aImageUrl];                    

                    itemList = [NSDictionary dictionaryWithObjectsAndKeys:shopping.listID,@"listID",shopping.brandName,@"brandName",shopping.itemName,@"itemName",shopping.itemQuantity,@"itemQuantity",shopping.imageURL,@"imageURL",nil];

                    // Add the Shopping object to the items Array
                    [items addObject:itemList];
                }
            }

            else { NSLog(@"Database Not Found");}

            // Release the compiled statement from memory
            sqlite3_finalize(compiledStatement);

        NSLog(@"%@",items);
        NSLog(@"%@",lists);

    }
    sqlite3_close(database);

}

//#******************************************************#

//                *******END Database*******

//#******************************************************#

-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    int rowcount;
    rowcount = [lists count];
    return rowcount;
}

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) 
    {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault 
                                      reuseIdentifier:CellIdentifier];    
    }

    // Set up the cell...

    NSString *cellValue = [[lists objectAtIndex:indexPath.row] objectForKey:@"listName"];

    cell.textLabel.text = cellValue;

    return cell;
}

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath 
{

    if ([[lists objectAtIndex:indexPath.row] objectForKey:@"listID"] != NULL) 
    {        
        NSString *listIndex = [[lists objectAtIndex:indexPath.row] objectForKey:@"listID"];
        int i = [listIndex intValue];
        NSLog(@"indexPath: %d",i);
    }

}

編輯**********

單個Sql語句返回多個Listname。 這是一個問題，因為我只需要每個列表名稱之一。

Answer 1

因此，首先，您要創建一個List對象，然后創建一個與List對象幾乎相同的NSDictionary對象。 為什么？ 為什么不只是將List對象添加到Array中呢？ 如果您不對List項中的屬性執行任何功能，則根本不要使用List對象，只需將字段直接放在NSDictionary中即可。

其次，不要執行兩個不同的SQL調用來獲取信息，而只能使用一個來同時獲取List和該列表的list_items。 然后，如果您使用的是List對象，請添加NSMutableArray屬性調用項，然后將listItems添加到該數組。 您可以在NSDictionary中執行相同的操作，只需為關鍵項添加NSMutableArray對象，然后將list_items添加至該數組。

現在，您可以設置表視圖以執行所需的操作。

修改答案以回應以下評論

Select * FROM List, List_Items WHERE List.list_id = List.list_id

Answer 2

任何對此感興趣的人都是我弄清楚的方法。 我得到列表的listID，然后創建一個數組並遍歷列表項，並與listID進行比較。 如果它們與listID相同，則將它們添加到數組中，並在完成for循環后將結果添加到我的dataobject協議中（以使其可用於下一個視圖），然后我將提供一個模式視圖控制器並加載數據對象的數組。 一旦我完成了模態視圖，就將dataobject設置回nil和Tada！ 有用。

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath 
{

    if ([[lists objectAtIndex:indexPath.row] objectForKey:@"listID"] != NULL) 
    {        
        [listTableView deselectRowAtIndexPath:indexPath animated:YES];
        NSString *listIndex = [[lists objectAtIndex:indexPath.row] objectForKey:@"listID"];

        NSMutableArray *itemArray = [[NSMutableArray alloc]init];

        int i; int itemCount = [items count];

        for (i = 0; i < itemCount; i++) 
        {
            if ([[[items objectAtIndex:i] objectForKey:@"listID"] isEqual:listIndex]) 
            {
                [itemArray addObject:[items objectAtIndex:i]];
                NSLog(@"Item Array:%@",itemArray);
            }
        }

        if (i == itemCount) 
        {
            AppDataObject* theDataObject = [self theAppDataObject];
            theDataObject.itemArray = itemArray;

            ItemView *temp = [[ItemView alloc] initWithNibName:@"ItemView" bundle:nil];
            [self presentModalViewController: temp animated: YES];
        }

    }

}