如何添加「加載更多」選項，以表視圖

Question

我的應用程序具有通過sqlite的DB填充表包含數據 所以它會導致延遲加載表視圖

這裏的巨大量的代碼

- (void) searchData { 
    //i=0; 
    [newSearchBar setShowsCancelButton:YES animated:YES]; 



    NSLog(@"search data started "); 

    NSLog(@" checking value %@",newSearchBar.text); 
    NSString *databaseName = @"imeating.sql"; 
    NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES); 
    NSString *documentsDir=[documentPaths objectAtIndex:0]; 
    NSString *databasePath=[documentsDir stringByAppendingPathComponent:databaseName]; 
    sqlite3 *database; 

    if (sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) 
    { 
     NSLog(@"with in if sqlite3 open"); 
     // Setup the SQL Statement and compile it for faster access 
     sqlite3_stmt *compiledStatement ; 
     const char *sqlStatement ; 

     /* if ([searchFlag isEqualToString:@"DEF"]) 
     { 
     sqlStatement = "select subitem_name, subitem_detail_id from subitem_detail limit 200" ; 
     } 
     else 
     {*/ 
     sqlStatement = "select category_id, upper(subitem_name), subitem_detail_id, protein, carbohydrates, fat, calorie from subitem_detail where subitem_name LIKE ? order by subitem_name limit ?,?" ; 
     NSLog(@"inside search b4 wildsearch %@",searchString); 

     wildSearch = [NSString stringWithFormat:@"%@%@",searchString, @"%"]; 

     NSLog(@"wildsearch %@",wildSearch); 

     [newSearchBar setShowsCancelButton:YES animated:YES]; 
     //NSLog(@"inside search : %@", wildSearch); 


     //} 

     if (sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) 
     { 

      NSLog(@"with in if sqlite3 prepare v2"); 
      // if (![searchFlag isEqualToString:@"DEF"]) 
      // { 
      sqlite3_bind_text(compiledStatement, 1, [wildSearch UTF8String], -1, SQLITE_TRANSIENT); 
      sqlite3_bind_int(compiledStatement, 2, llimit); 
      sqlite3_bind_int(compiledStatement, 3, ulimit); 

      // } 
      // Loop through the results and add it to array 

      if (llimit <200){ 
       NSLog(@"with in if limit < 200"); 

       itemArray = [[NSMutableArray alloc] init] ; 
      } 

      while (sqlite3_step(compiledStatement) == SQLITE_ROW) { 

       //NSLog(@" while sqlite3 step"); 

       NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init] ; 
       //[itemDic release]; 
       //itemDic = nil ; 
       itemDic = [[[NSMutableDictionary alloc] init] autorelease]; 


       NSString *categoryId = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 0)]; 
       NSString *itemName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 1)]; 
       NSString *itemId = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 2)]; 
       NSString *protein = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 3)]; 
       NSString *carbo = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 4)]; 
       NSString *fat = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 5)]; 
       NSString *calorie = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 6)]; 

       /* NSLog(@"itemname : %@", itemName); 
       NSLog(@"itemid : %@", itemId); 
       NSLog(@"\n");*/ 

       [itemDic setObject:categoryId forKey:@"categoryId"]; 
       [itemDic setObject:itemId forKey:@"itemId"]; 
       [itemDic setObject:itemName forKey:@"itemName"]; 
       [itemDic setObject:protein forKey:@"protein"]; 
       [itemDic setObject:carbo forKey:@"carbohydrate"]; 
       [itemDic setObject:fat forKey:@"fat"]; 
       [itemDic setObject:calorie forKey:@"calorie"]; 

       [itemArray addObject:itemDic]; 
       if (ulimit%200 == 0) 
       { 
        //activity = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActionSheetStyleDefault]; 
        //[activity startAnimating]; 
        [newTableView reloadData]; 
        //[newSearchBar setShowsCancelButton:YES animated:YES]; 
        //NSLog(@"list all views after 1st reload: %@", [self.navigationController.viewControllers description]); 
        //[newTableView addSubview:activity]; 
        //[activity stopAnimating]; 
        //[activity release]; 
        //NSLog(@" with in if"); 
       } 
       [pool drain]; 
      } /*else 
       { 
       UIAlertView *alert = [[UIAlertView alloc ] initWithTitle:@"Error" message:@"sqlite rows not returned" delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil] ; 
       [alert show]; 
       }*/ 


     } 
    } else 
    { 
     UIAlertView *alert = [[UIAlertView alloc ] initWithTitle:@"Error" message:@"DataBase Path doesn't exists" delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil] ; 
     [alert show]; 
    } 

    //NSLog(@"itemArray desc : %@",[itemArray description]); 

} 

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView 
{ 
    //NSLog(@"Inside number of sections in tableview"); 
    return 1; 

} 

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section 
{ 
    return [itemArray count] ; 

} 

// Customize the appearance of table view cells. 
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath 
{ 
    static NSString *CellIdentifier = @"Cell"; 

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

    //NSLog(@"indexpath row val : %d", indexPath.row); 

    tableIndex = indexPath ; 

    //NSLog(@"print indexpath row : %d", indexPath.row); 
    //NSLog(@"print limit : %d", limit); 

    if (indexPath.row > limit) 
    { 
     llimit = llimit+200 ; 
     ulimit = ulimit+200 ; 

     NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; 

     //[opq cancelAllOperations]; 
     NSLog(@"before ns operation"); 

     opq = [NSOperationQueue new]; 
     //opq = [[NSOperationQueue alloc] init]; 
     //[opq setMaxConcurrentOperationCount:2]; 

     // [self performSelectorOnMainThread:@selector(searchData) withObject:nil waitUntilDone:YES]; 

     NSInvocationOperation *op = [[[NSInvocationOperation alloc] initWithTarget:self selector:@selector(searchData) object:nil] autorelease]; 



     [opq addOperation:op]; 

     NSLog(@"after ns operation"); 
     //[op release]; 
     //[opq release]; 

     [pool drain]; 
     i++; 
     limit = limit + 120 ; 
     NSLog(@"i=%d",i); 

     //[cell setText:[[itemArray objectAtIndex:indexPath.row] valueForKey:@"itemName"]]; 
    } 

    // Configure the cell. 
    //[cell setText:[[itemArray objectAtIndex:indexPath.row] valueForKey:@"itemName"]]; 
    cell.textLabel.text = [[itemArray objectAtIndex:indexPath.row] valueForKey:@"itemName"] ; 
    NSString *pval, *cval, *fval, *cal ; 
    if ([[[itemArray objectAtIndex:indexPath.row] valueForKey:@"protein"] length] <= 5) 
     pval = [[itemArray objectAtIndex:indexPath.row] valueForKey:@"protein"]; 
    else 
     pval = [[[itemArray objectAtIndex:indexPath.row] valueForKey:@"protein"] substringWithRange:NSMakeRange(0, 5)]; 

    if ([[[itemArray objectAtIndex:indexPath.row] valueForKey:@"carbohydrate"] length] <= 5) 
     cval = [[itemArray objectAtIndex:indexPath.row] valueForKey:@"carbohydrate"]; 
    else 
     cval = [[[itemArray objectAtIndex:indexPath.row] valueForKey:@"carbohydrate"] substringWithRange:NSMakeRange(0, 5)]; 

    if ([[[itemArray objectAtIndex:indexPath.row] valueForKey:@"fat"] length] <= 5) 
     fval = [[itemArray objectAtIndex:indexPath.row] valueForKey:@"fat"]; 
    else 
     fval = [[[itemArray objectAtIndex:indexPath.row] valueForKey:@"fat"] substringWithRange:NSMakeRange(0, 5)]; 

    if ([[[itemArray objectAtIndex:indexPath.row] valueForKey:@"calorie"] length] <= 5) 
     cal = [[itemArray objectAtIndex:indexPath.row] valueForKey:@"calorie"]; 
    else 
     cal = [[[itemArray objectAtIndex:indexPath.row] valueForKey:@"calorie"] substringWithRange:NSMakeRange(0, 5)]; 

    cell.detailTextLabel.text = 
    [NSString stringWithFormat:@"Prot: %@ Carb: %@ Fat: %@ Cal: %@", pval, cval, fval, cal] ; 
    return cell; 
} 

我需要「加載更多」我的表視圖，從sqlite的DB加載記錄限制的特定時期

Answer 1

添加+ 1行的數量在部分行中的按鈕：

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section 
{ 
    return [itemArray count] + 1; 

} 

• 然後在的cellForRowAtIndexPath，查看是否indexPath.row比[itemArray計數]更大。如果是，則將文本「加載更多...」作爲單元格的標題。

• 在didSelectRowAtIndexPath方法中，查看是否indexPath.row等於[itemArray計數。如果是這種情況，那麼向itemArray添加更多的結果，然後調用[tableView reloadData]。

• 對於一些UI的改進，你可以在表格視圖頂部添加UIActivityIndi​​cator表明一些處理在後臺繼續。