UITableView重用節標題視圖：使用UITableViewRowAnimationFade時，標題視圖消失

Question

我更喜歡使用UITableView創建具有2級層次結構的表，如此圖片。每次用戶點擊標題，內容將崩潰或展開。 3天后的研究，我發現，有2技術：

1.custom的UITableViewCell與自身另一個表

2，採用節頭視圖。

現在我決定使用第二個。並且因爲UITableView does not re-use section view（儘管UITableView包含2個私有變量：_reusableHeaderViews & _reusableFooterViews :)，所以我創建了一些自定義方法來執行此任務。每一次都沒問題，除了1個bug：當我使用方法reloadSections：withRowAnimation with UITableViewRowAnimationFade，標題視圖變成空白視圖。

這裏是我的代碼：

#import "MasterViewController.h" 

@interface MasterViewController() 
//remember current section 
@property (assign, nonatomic) NSInteger curSession; 
@property (strong, nonatomic) NSMutableDictionary *reusableHeaderViews; 
@end 

@implementation MasterViewController 

@synthesize reusableHeaderViews = _reusableHeaderViews; 
@synthesize tableView = _tableView; 
@synthesize curSession = _curSession; 
@synthesize detailViewController = _detailViewController; 

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil 
{ 
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; 
    if (self) { 
     self.title = NSLocalizedString(@"Master", @"Master"); 
    } 
    return self; 
} 

- (void)viewDidLoad 
{ 
    [super viewDidLoad]; 
    self.curSession = -1; 
} 

- (void)viewDidUnload 
{ 
    [super viewDidUnload]; 
    // Release any retained subviews of the main view. 
} 

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation 
{ 
    return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown); 
} 

//method for adding header view into reuse-array 
- (void)registerHeaderView:(UITableViewCell *)headerView forReuseIdentifier:(NSString *)reuseIdentifier 
{ 
    NSMutableDictionary *reusableDictionary = [self reusableHeaderViews]; 
    if (reusableDictionary == nil) 
    { 
     reusableDictionary = [[NSMutableDictionary alloc] init]; //creates a storage dictionary if one doesn’t exist 
     self.reusableHeaderViews = reusableDictionary; 
    } 

    NSMutableArray *arrayForIdentifier = [[self reusableHeaderViews] objectForKey:reuseIdentifier]; 
    if (arrayForIdentifier == nil) 
    { 
     //creates an array to store views sharing a reuse identifier if one does not exist 
     arrayForIdentifier = [[NSMutableArray alloc] init];   
     [reusableDictionary setObject:arrayForIdentifier forKey:reuseIdentifier]; 
    } 

    [arrayForIdentifier addObject:headerView]; 
} 

//get header view in reuse-array 
- (UITableViewCell *)reuseableHeaderForIdentifier:(NSString *)reuseIdentifier 
{ 
    NSMutableArray *arrayOfViewsForIdentifier = [[self reusableHeaderViews] objectForKey:reuseIdentifier]; 

    if (arrayOfViewsForIdentifier == nil) 
    { 
     return nil; //We don’t have any of this kind! 
    } 

    NSInteger indexOfAvailableHeaderView = [arrayOfViewsForIdentifier indexOfObjectPassingTest:^BOOL(id obj, NSUInteger idx, BOOL *stop) 
              { 
               //If my view doesn’t have a superview, it’s not on-screen. 
               return ![obj superview]; 
              }]; 

    if (indexOfAvailableHeaderView != NSNotFound) 
    { 
     UITableViewCell *headerView = [arrayOfViewsForIdentifier objectAtIndex:indexOfAvailableHeaderView]; 
     return headerView; //Success! 
    } 

    return nil; 
} 

#pragma mark - Table View 

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView 
{ 
    return 15; 
} 

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section 
{ 
    if (_curSession == section) 
     return section; 
    return 0; 
} 

- (UIView*) tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section 
{ 
    static NSString *headerReuseIdentifier = @"Header"; 
    UITableViewCell *cell = [self reuseableHeaderForIdentifier:headerReuseIdentifier]; 
    if(cell == nil) 
    { 
     //Didn’t locate a reusable 
     cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@""]; 
     [self registerHeaderView:cell forReuseIdentifier:headerReuseIdentifier]; 
     UITapGestureRecognizer *tapGR = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(openSection:)]; 
     tapGR.numberOfTapsRequired = 1; 
     [cell addGestureRecognizer:tapGR]; 
     cell.backgroundColor = [UIColor redColor]; 
    } 
    cell.tag = section; 
    cell.textLabel.text = [NSString stringWithFormat:@"Section title %i", section]; 

    return cell; 
} 

- (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]; 
     cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator; 
    } 

    cell.textLabel.text = [NSString stringWithFormat:@"Row %i - section %i", indexPath.row, indexPath.section]; 
    return cell; 
} 

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

} 

- (void) openSection:(id)sender 

{ 
    NSInteger section = [[(UITapGestureRecognizer*)sender view] tag]; 
    if(_curSession == -1) 
    { 
     _curSession = section; 
     [_tableView reloadSections:[NSIndexSet indexSetWithIndex:_curSession] withRowAnimation:UITableViewRowAnimationFade]; 
    } 
    else if(_curSession == section) 
    { 
     _curSession = -1; 
     [_tableView reloadSections:[NSIndexSet indexSetWithIndex:section] withRowAnimation:UITableViewRowAnimationFade]; 
    } 
    else if(_curSession != section) 
    { 
     NSInteger temp = _curSession; 
     _curSession = -1; 
     [_tableView reloadSections:[NSIndexSet indexSetWithIndex:temp] withRowAnimation:UITableViewRowAnimationFade]; 
     _curSession = section; 
     [_tableView reloadSections:[NSIndexSet indexSetWithIndex:section] withRowAnimation:UITableViewRowAnimationFade]; 
    } 
} 

@end 

Answer 1

這是一個有點晚，但也許會有人有類似的問題。

您可以嘗試使用這個組件：https://github.com/serverdensity/ios-SDNestedTable