當在UITableView中移動單元格時，如何讓單元格保持靜止？

Question

我有一個佔用點的人列表。我希望用戶能夠將這些人重新安排到不同的地方，但是有些地方是禁止的。我認爲使用UITableView的重新排列功能很容易實現。但是，我無法弄清楚如何讓不可用的斑點保持靜止。

例如，我想將Activia Boulanger移到第5點。灰色細胞應該是不可移動的細胞。

開始觀看：

的UITableView的自動做些什麼：

我想要的UITableView做什麼：

設置tableView:canMoveRowAtIndexPath:似乎只是阻止您移動細胞，但不會阻止細胞對其他細胞的移動作出反應。

任何幫助將不勝感激。 感謝

---

UPDATE： 下面是針對該問題的設置一些示例代碼。我沒有將我的努力納入解決方案，因爲他們都失敗了，會讓事情混亂起來。

#import "LDYViewController.h" 

static NSString * unmoveableCellId = @"NoMove"; 
static NSString * moveableCellId = @"OkMove"; 

@implementation LDYViewController 
@synthesize tableView; 
@synthesize peopleList; 

- (void)viewDidLoad 
{ 
    [super viewDidLoad]; 

    peopleList = [[NSMutableArray alloc] initWithObjects: 
        @"Belinda Boomer", @"Activia Boulanger", @"Arnold Carter", [NSNull null], @"Attila Creighton", [NSNull null], @"Bruce Cleary", [NSNull null], nil]; 
    [tableView setEditing:YES]; 
    // Do any additional setup after loading the view, typically from a nib. 
} 

#pragma mark - Table view data source 

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView 
{ 
    return 1; 
} 

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section 
{ 
    return peopleList.count; 
} 

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

    if([peopleList objectAtIndex:indexPath.row] == [NSNull null]) { 
     cell = [tableView dequeueReusableCellWithIdentifier:unmoveableCellId]; 
     if (cell == nil) { 
      cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:unmoveableCellId]; 
      cell.userInteractionEnabled = NO; 
      cell.contentView.backgroundColor = [UIColor grayColor]; 
     } 
    } else { 
     cell = [tableView dequeueReusableCellWithIdentifier:moveableCellId]; 
     if (cell == nil) { 
      cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:moveableCellId]; 
      NSString * name = [peopleList objectAtIndex:indexPath.row]; 
      cell.textLabel.text = name; 
     }   
    } 

    return cell; 
} 

- (void) tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)sourceIndexPath toIndexPath:(NSIndexPath *)destinationIndexPath { 
} 

- (NSIndexPath *)tableView:(UITableView *)tableView 
targetIndexPathForMoveFromRowAtIndexPath:(NSIndexPath *)sourceIndexPath 
     toProposedIndexPath:(NSIndexPath *)proposedDestinationIndexPath { 
    return proposedDestinationIndexPath; 
} 

- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath 
{ 
    if([peopleList objectAtIndex:indexPath.row] == [NSNull null]) { 
     return NO; 
    } 

    return YES; 
}  
@end 

Answer 1

做你的模型在正常重排的邏輯，那麼當它這樣做，把空回在你要他們。發佈的代碼不包括模型，所以這裏是一個合理的模型來說明：

// always leave our array with a null at indexes 3,5,7 
// i'm sure you have better logic about where nulls go, but just to illustrate 
- (void)addNulls { 

    NSMutableArray *answer = [NSMutableArray array]; 
    for (id object in self.peopleList) { 
     if (![object isKindOfClass:[NSNull self]]) { 
      [answer addObject:object]; 
     } 
    } 

    assert(answer.count >= 4); 
    [answer insertObject:[NSNull null] atIndex:3]; 
    [answer insertObject:[NSNull null] atIndex:5]; 
    [answer insertObject:[NSNull null] atIndex:7]; 
    self.peopleList = answer; 
} 

// build a pretend model with nulls 
- (NSMutableArray *)peopleList { 

    if (!_peopleList) { 
     _peopleList = [NSMutableArray array]; 
     [_peopleList addObject:@"Moe"]; 
     [_peopleList addObject:@"Larry"]; 
     [_peopleList addObject:@"Curly"]; 
     [_peopleList addObject:[NSNull null]]; 
     [_peopleList addObject:@"Groucho"]; 
     [_peopleList addObject:[NSNull null]]; 
     [_peopleList addObject:@"Chico"]; 
     [_peopleList addObject:[NSNull null]]; 
     [_peopleList addObject:@"Harpo"]; 
    } 
    return _peopleList; 
} 



// normal rearrange logic, then fix your array up 
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath { 

    // reorder the list with the typical logic, ignoring nulls 
    NSString *stringToMove = [self.peopleList objectAtIndex:fromIndexPath.row]; 
    [self.peopleList removeObjectAtIndex:fromIndexPath.row]; 
    [self.peopleList insertObject:stringToMove atIndex:toIndexPath.row]; 

    // now put nulls into the positions you want them 
    [self addNulls]; 
    [self.tableView reloadData]; 
} 

Answer 2

您可以通過這樣做：

- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath{ 

在這種方法中，你需要檢查從indexIndexPath和toIndexPath檢查，如果用戶移動到一個無效的位置。將tableview的數據源修改爲放回單元格或將其移動到正確的位置。

Answer 3

試試這個：

- (NSIndexPath *)tableView:(UITableView *)tableView targetIndexPathForMoveFromRowAtIndexPath:(NSIndexPath*)sourceIndexPath 
     toProposedIndexPath:(NSIndexPath *)proposedDestinationIndexPath 

您可以檢查proposedDestinationIndexPath，如果你不想動行，你可以返回sourceIndexPath則行將被移回，否則返回proposedDestinationIndexPath。

Answer 4

我面臨類似的問題，並解決它。

創建2個部分，並把所有灰色排在第2

-(NSIndexPath *)tableView:(UITableView *)tableView targetIndexPathForMoveFromRowAtIndexPath:(NSIndexPath *)sourceIndexPath toProposedIndexPath:(NSIndexPath *)proposedDestinationIndexPath{ 

if (proposedDestinationIndexPath.section == 1) 
    return sourceIndexPath; 
else 
    return proposedDestinationIndexPath; 

}