tableView數據未顯示

Question

我遇到問題。當我實現下面的代碼到一個tableViewController我沒有問題，並顯示擴大/收縮表就好了。但是，當我嘗試將代碼實現到viewController中的tableView中時，它不會顯示。任何想法發生了什麼？我在我的.h文件中包含了tableview委託和數據源文件。

這裏是頭文件：

#import <UIKit/UIKit.h> 

@interface MainViewController : UIViewController <UITableViewDataSource, UITableViewDelegate> 
{ 
NSArray *topItems; 
NSMutableArray *subItems; // array of arrays 

int currentExpandedIndex; 
} 

@property (weak, nonatomic) IBOutlet UITableView *tableView; 



@end 

這裏是.m文件

#import "MainViewController.h" 
#define NUM_TOP_ITEMS 20 
#define NUM_SUBITEMS 6 


@interface MainViewController() 

@end 


@implementation MainViewController 


- (id)init { 
self = [super init]; 

if (self) { 
    topItems = [[NSArray alloc] initWithArray:[self topLevelItems]]; 
    subItems = [NSMutableArray new]; 
    currentExpandedIndex = -1; 

    for (int i = 0; i < [topItems count]; i++) { 
     [subItems addObject:[self subItems]]; 
    } 
} 
return self; 
} 

#pragma mark - Data generators 

- (NSArray *)topLevelItems { 
NSMutableArray *items = [NSMutableArray array]; 

for (int i = 0; i < NUM_TOP_ITEMS; i++) { 
    [items addObject:[NSString stringWithFormat:@"Item %d", i + 1]]; 
} 

return items; 
} 

- (NSArray *)subItems { 
NSMutableArray *items = [NSMutableArray array]; 
int numItems = arc4random() % NUM_SUBITEMS + 2; 

for (int i = 0; i < numItems; i++) { 
    [items addObject:[NSString stringWithFormat:@"SubItem %d", i + 1]]; 
} 

return items; 
} 

#pragma mark - View management 

- (void)viewDidLoad { 
[super viewDidLoad]; 
} 

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

#pragma mark - Table view data source 

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

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { 
return [topItems count] + ((currentExpandedIndex > -1) ? 
[[subItems  objectAtIndex:currentExpandedIndex] count] : 0); 
} 

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath: 
(NSIndexPath  *)indexPath { 
static NSString *ParentCellIdentifier = @"ParentCell"; 
static NSString *ChildCellIdentifier = @"ChildCell"; 

BOOL isChild = 
currentExpandedIndex > -1 
&& indexPath.row > currentExpandedIndex 
&& indexPath.row <= currentExpandedIndex + 
[[subItems objectAtIndex:currentExpandedIndex] count]; 

UITableViewCell *cell; 

if (isChild) { 
    cell = [tableView dequeueReusableCellWithIdentifier:ChildCellIdentifier]; 
} 
else { 
    cell = [tableView dequeueReusableCellWithIdentifier:ParentCellIdentifier]; 
} 


if (cell == nil) { 
    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:ParentCellIdentifier]; 
} 

if (isChild) { 
    cell.detailTextLabel.text = 
[[subItems objectAtIndex:currentExpandedIndex] 
objectAtIndex:indexPath.row - currentExpandedIndex - 1]; 
} 
else { 
    int topIndex = (currentExpandedIndex > -1 && indexPath.row > currentExpandedIndex) 
    ? indexPath.row - [[subItems objectAtIndex:currentExpandedIndex] count] 
    : indexPath.row; 

    cell.textLabel.text = [topItems objectAtIndex:topIndex]; 
    cell.detailTextLabel.text = @""; 
} 

return cell; 
} 

#pragma mark - Table view delegate 

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { 
BOOL isChild = 
currentExpandedIndex > -1 
&& indexPath.row > currentExpandedIndex 
&& indexPath.row <= currentExpandedIndex + 
[[subItems objectAtIndex:currentExpandedIndex] count]; 

if (isChild) { 
    NSLog(@"A child was tapped, do what you will with it"); 
    return; 
} 

[self.tableView beginUpdates]; 

if (currentExpandedIndex == indexPath.row) { 
    [self collapseSubItemsAtIndex:currentExpandedIndex]; 
    currentExpandedIndex = -1; 
} 
else { 

    BOOL shouldCollapse = currentExpandedIndex > -1; 

    if (shouldCollapse) { 
     [self collapseSubItemsAtIndex:currentExpandedIndex]; 
    } 

    currentExpandedIndex = (shouldCollapse && indexPath.row > currentExpandedIndex) ? indexPath.row - [[subItems objectAtIndex:currentExpandedIndex] count] : indexPath.row; 

    [self expandItemAtIndex:currentExpandedIndex]; 
} 

[self.tableView endUpdates]; 

} 

- (void)expandItemAtIndex:(int)index { 
NSMutableArray *indexPaths = [NSMutableArray new]; 
NSArray *currentSubItems = [subItems objectAtIndex:index]; 
int insertPos = index + 1; 
for (int i = 0; i < [currentSubItems count]; i++) { 
    [indexPaths addObject:[NSIndexPath indexPathForRow:insertPos++ inSection:0]]; 
} 
[self.tableView insertRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationFade]; 
[self.tableView scrollToRowAtIndexPath: 
[NSIndexPath indexPathForRow:index inSection:0] 
atScrollPosition:UITableViewScrollPositionTop animated:YES]; 

} 

- (void)collapseSubItemsAtIndex:(int)index { 
NSMutableArray *indexPaths = [NSMutableArray new]; 
for (int i = index + 1; i <= index + [[subItems objectAtIndex:index] count]; i++) { 
    [indexPaths addObject:[NSIndexPath indexPathForRow:i inSection:0]]; 
} 
[self.tableView deleteRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationFade]; 

} 
@end 

Answer 1

您需要設置委託和數據源在您的viewDidLoad中或在你的XIB。

在代碼：

[self.tableView setDelegate:self]; 
[self.tableView setDataSource:self]; 

在你的控制器：

- (void)viewDidLoad { 
    [super viewDidLoad]; 
    [self.tableView setDelegate:self]; 
    [self.tableView setDataSource:self]; 
}