[英]UITableView custom cells disappear when trying to scroll
我有一個UITableViewController,它具有帶有自定義單元格的表視圖(它們具有子類和xib)。 問題是我從博客加載數據並顯示確定,但是當我嘗試滾動或觸摸時,單元格會重置,就像它們沒有加載一樣。
這是它出現的方式:
當我嘗試滾動時會發生這種情況:
這是我的View Controller代碼:
#import "TLDRCategoryViewController.h"
@interface TLDRCategoryViewController ()
@property(nonatomic,strong) IBOutlet UIView *headerView;
@property(nonatomic,strong) NSMutableArray *posts;
@property(nonatomic, assign, readonly) TLDRTag category;
@property(nonatomic, strong) IBOutlet UILabel *category_label;
@end
@implementation TLDRCategoryViewController
@synthesize headerView = _headerView, posts = _posts, category = _category, category_label = _category_label;
- (id)initWithStyle:(UITableViewStyle)style
{
self = [super initWithStyle:style];
if (self) {
// Custom initialization
}
return self;
}
-(void)setCategory:(TLDRTag)_cat {
_category = _cat;
}
- (void)viewDidLoad
{
[super viewDidLoad];
self.tableView.tableHeaderView = _headerView;
_category_label.text = [TLDRHelper showableNameForTag:_category];
_category_label.textColor = [TLDRHelper colorForTag:_category];
TLDRRetriever *retriever = [[TLDRRetriever alloc] initWithDelegate:self];
[retriever postsByCategory:_category];
if (_posts == nil)
_posts = [[NSMutableArray alloc] init];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
-(void)postsLoaded:(NSDictionary *)postsDict {
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, (unsigned long)NULL), ^(void) {
for (NSDictionary *key in postsDict[@"response"][@"posts"]) {
TLDRNewsItem *newsPost = [[TLDRNewsItem alloc] initWithDictionary:key];
[self.posts addObject:newsPost];
}
dispatch_sync(dispatch_get_main_queue(), ^{
[self.tableView reloadData];
});
});
}
#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
// Return the number of sections.
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// Return the number of rows in the section.
return [self.posts count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"TLDRNewsCell";
TLDRNewsCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil){
NSArray *topLevelObjects = [[NSBundle mainBundle] loadNibNamed:@"TLDRNewsCell" owner:nil options:nil];
for(id currentObject in topLevelObjects) {
if([currentObject isKindOfClass:[TLDRNewsCell class]]) {
cell = (TLDRNewsCell *)currentObject;
break;
}
}
}
cell.title.text = ((TLDRNewsItem*)self.posts[indexPath.row]).articleTitle;
cell.content.text = ((TLDRNewsItem*)self.posts[indexPath.row]).articleTLDR;
return cell;
}
-(float)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
NSString *text = ((TLDRNewsItem*)self.posts[indexPath.row]).articleTLDR;
CGSize textSize = [text sizeWithFont:[UIFont systemFontOfSize:14.0f] constrainedToSize:CGSizeMake(self.tableView.frame.size.width - PADDING * 3, 1000.0f)];
return textSize.height + PADDING * 3;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
// Navigation logic may go here. Create and push another view controller.
/*
<#DetailViewController#> *detailViewController = [[<#DetailViewController#> alloc] initWithNibName:@"<#Nib name#>" bundle:nil];
// ...
// Pass the selected object to the new view controller.
[self.navigationController pushViewController:detailViewController animated:YES];
*/
}
這是TLDRRetriever的相關部分:
-(void)postsByCategory:(NSInteger)cat {
NSString *string_cat = @"";
switch (cat) {
case TLDRTagWorldNews:
string_cat = @"world%20news";
break;
case TLDRTagBusiness:
string_cat = @"business";
break;
case TLDRTagDesign:
string_cat = @"design";
break;
case TLDRTagEntertainment:
string_cat = @"entertainment";
break;
case TLDRTagFacts:
string_cat = @"facts";
break;
case TLDRTagHealth:
string_cat = @"health";
break;
case TLDRTagPolitics:
string_cat = @"politics";
break;
case TLDRTagScience:
string_cat = @"science";
break;
case TLDRTagSports:
string_cat = @"sports";
break;
case TLDRTagTech:
string_cat = @"tech";
break;
case TLDRTagWeb:
string_cat = @"web";
break;
default:
string_cat = @"";
break;
}
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
dispatch_async(queue, ^{
NSData* data = [NSData dataWithContentsOfURL:[NSURL URLWithString:[NSString stringWithFormat:@"%@%@", kTLDRAPIURLCats, string_cat]]];
NSError *error;
NSDictionary* json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
[[self delegate] postsLoaded:json];
});
}
我在該應用程序上也有一個幾乎精確的視圖控制器,它工作正常(我正在使用該控制器的大部分代碼,並且這個可以重用於其他類似的類別)。 該控制器是批量分配的(我分配了11個控制器並將它們保存在一個數組中)。 我無法調試這個,所以我不知道發生了什么。 代碼中有什么問題嗎? 謝謝!
修復程序與控制器或類似的東西無關:它是根視圖控制器。 視圖沒有保留在內存中,所以我只為每個控制器制作了一個ivar而不是循環它們並修復了應用程序:)
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