在NSMutableArray中使用BOOL對象來確定單元格狀態

Question

我正在使用引用爲'stateArray'的NSMutableArray。 stateArray需要簡單地保存我的單元格的BOOL值，以確定它們是否被選中。這裏是我的代碼..

stateArray在我的.h：

@property (nonatomic, strong) NSMutableArray *stateArray; 

然後stateArray 不是合成。需要在整個陣列中填寫NO，以便在選中單元格時，NO可以替換爲YES。目前此代碼正在爲每個單元格打印0的狀態陣列（NSLog位於我的cellForRowAtIndexPath:的if (showCheckmark == YES)中）。

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath 
{ 
    [[UITableViewCell appearance] setTintColor:[UIColor colorWithHexString:@"#669900"]]; 

    #define CHECK_NULL_STRING(str) ([str isKindOfClass:[NSNull class]] || !str)?@"":str 

    static NSString *CellIdentifier = @"inviteCell"; 
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath]; 

    //Customization 
    cell.textLabel.highlightedTextColor = [UIColor colorWithHexString:@"#669900"]; 
    cell.selectionStyle = UITableViewCellSelectionStyleGray; 
    cell.backgroundColor = [UIColor blackColor]; 
    cell.textLabel.textColor = [UIColor whiteColor]; 
    //Ignore this, it's for UISearchBar 
    BOOL isSearching = tableView != self.tableView; 
    NSArray *arrayToUse = (isSearching ? searchResults : contactsObjects); 
    id p = arrayToUse[indexPath.row]; 

    NSString *fName = (__bridge_transfer NSString *)(ABRecordCopyValue((__bridge ABRecordRef)(p), kABPersonSortByFirstName)); 
    NSString *lName = (__bridge_transfer NSString *)(ABRecordCopyValue((__bridge ABRecordRef)(p), kABPersonSortByLastName)); 
    cell.textLabel.text = [NSString stringWithFormat:@"%@ %@", CHECK_NULL_STRING(fName), CHECK_NULL_STRING(lName)]; 

    _stateArray = [NSMutableArray array]; 
    for (int i = 0 ; i != contactsObjects.count ; i++) [_stateArray addObject:@(NO)]; 

    BOOL showCheckmark = [[_stateArray objectAtIndex:indexPath.row] boolValue]; 

    if (showCheckmark == YES) 
    { 
     cell.accessoryType = UITableViewCellAccessoryCheckmark; 
     NSLog(@"It hit showCheckmark = YES, and stateArray is %@",_stateArray[indexPath.row]); 
    } 
    else 
    { 
     cell.accessoryType = UITableViewCellAccessoryNone; 
     NSLog(@"It hit showCheckmark = NO, and stateArray is %@",_stateArray[indexPath.row]); 
    } 

    return cell; 
} 

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath; 
{  
    id object = contactsObjects[indexPath.row]; 
    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath]; 

    if (cell.accessoryType == UITableViewCellAccessoryNone) 
    { 
     cell.accessoryType = UITableViewCellAccessoryCheckmark; 
     [_stateArray replaceObjectAtIndex:indexPath.row withObject:@(YES)]; 
     [selectedObjects addObject:object]; 
    } 
    else 
    { 
     cell.accessoryType = UITableViewCellAccessoryNone; 
     [_stateArray replaceObjectAtIndex:indexPath.row withObject:@(NO)]; 
     [selectedObjects removeObject:object]; 
    } 

    //slow-motion selection animation. 
    [tableView deselectRowAtIndexPath:indexPath animated:YES]; 
} 

Answer 1

要跟蹤選定的項目來填充_stateArray，使用的Dictionary代替NSMutableArray並保持indexPath.row爲鍵和選擇作爲對應的值。

而不是使用BOOL's數組進行這些操作，您可以更新代碼如下。

@property (nonatomic, strong) NSMutableDictionary * selectedRowCollection; 

- (void)viewDidLoad{ 

    self.selectedRowCollection = [[NSMutableDictionary alloc] init]; 
} 

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath; 
{  
    id object = contactsObjects[indexPath.row]; 
    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath]; 

    if (cell.accessoryType == UITableViewCellAccessoryNone) 
    { 
     cell.accessoryType = UITableViewCellAccessoryCheckmark; 
     [self.selectedRowCollection setObject:@"1" forKey:[NSString stringWithFormat:@"%d",indexPath.row]]; 
    } 
    else 
    { 
     cell.accessoryType = UITableViewCellAccessoryNone; 
     [self.selectedRowCollection removeObjectForKey:[NSString stringWithFormat:@"%d",indexPath.row]]; 
    } 

    //slow-motion selection animation. 
    [tableView deselectRowAtIndexPath:indexPath animated:YES]; 
} 

    - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath 
{ 
    BOOL showCheckmark = [[self.selectedRowCollection valueForKey:[NSString stringWithFormat:@"%d",indexPath.row]] boolValue]; 

    if (showCheckmark == YES) 
    { 
     cell.accessoryType = UITableViewCellAccessoryCheckmark; 

    } 
    else 
    { 
     cell.accessoryType = UITableViewCellAccessoryNone; 
    } 
} 

注：不要忘記從詞典中刪除詞典項目，而重裝一個新的tableview數據集。

Answer 2

BOOL值包裹着NSNumber，這就是爲什麼你得到的0：

_stateArray = [NSMutableArray array]; 
for (int i = 0 ; i != contactsObjects.count ; i++) [_stateArray addObject:@(NO)]; 

BOOL showCheckmark = [[_stateArray objectAtIndex:indexPath.row] boolValue]; 

if (showCheckmark == YES) 
{ 
    cell.accessoryType = UITableViewCellAccessoryCheckmark; 
    NSLog(@"It hit showCheckmark = YES, and stateArray is %@",[[_stateArray objectAtIndex:indexPath.row] boolValue] ? @"YES" : @"NO"); 
} 
else 
{ 
    cell.accessoryType = UITableViewCellAccessoryNone; 
    NSLog(@"It hit showCheckmark = NO, and stateArray is %@",[[_stateArray objectAtIndex:indexPath.row] boolValue] ? @"YES" : @"NO"); 
} 

BOOL沒有對象，所以你不能使用%@格式說明。您需要處理這個手動

Answer 3

試試這個，

更新您的循環由

for (int i = 0 ; i != contactsObjects.count ; i++) { 

    [_stateArray addObject:[NSNumber numberWithBool:NO]]; 
}