我在我的应用程序中制作 UICollectionView 时遇到了一些问题。我使用 IB 而不是故事板。这个问题的底部是我的 .h 和 .m 代码。在 IB 中，我添加了一个 UICollectionViewController 并告诉它我为它创建的 Obj-C 类的类。但是，当我运行它时，我得到的只是一个黑色视图。
。H：
#import <UIKit/UIKit.h>
@class WebViewController;
@class WebViewController2;
@interface GridLayout : UICollectionViewController <UICollectionViewDataSource, UICollectionViewDelegate> {
NSOperationQueue *_queue;
NSArray *_feeds;
NSMutableArray *_allEntries;
WebViewController *_webViewController;
UIActivityIndicatorView *activity;
WebViewController2 *_webViewController2;
IBOutlet UIBarButtonItem *redo;
IBOutlet UINavigationBar *myNavigationBar;
NSString *theurl;
}
-(IBAction)sendtofriend;
-(IBAction)refreshing;
@property (nonatomic, retain) NSString *theurl;
@property (retain) NSOperationQueue *queue;
@property (retain) NSArray *feeds;
@property (retain) NSMutableArray *allEntries;
@property (retain) WebViewController *webViewController;
@property (retain) UIActivityIndicatorView *activity;
@property (retain) WebViewController2 *webViewController2;
@end
米：
#import "GridLayout.h"
#import "RSSEntry.h"
#import "ASIHTTPRequest.h"
#import "GDataXMLNode.h"
#import "Reachability.h"
#import "GDataXMLElement-Extras.h"
#import "NSDate+InternetDateTime.h"
#import "NSArray+Extras.h"
#import "WebViewController.h"
#import "SettingsViewController.h"
#import "WebViewController2.h"
#import "Cell.h"
#import "ASINetworkQueue.h"
#import "UIImageView+WebCache.h"
@implementation GridLayout
@synthesize allEntries = _allEntries;
@synthesize feeds = _feeds;
@synthesize queue = _queue;
@synthesize webViewController = _webViewController;
@synthesize activity;
@synthesize webViewController2 = _webViewController2;
- (void)refresh {
self.allEntries = [NSMutableArray array];
self.queue = [[[NSOperationQueue alloc] init] autorelease];
self.feeds = [NSArray arrayWithObjects:@"http://feeds.feedburner.com/Ipreacherblog",
nil];
for (NSString *feed in _feeds) {
NSURL *url = [NSURL URLWithString:feed];
ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];
[request setDelegate:self];
[_queue addOperation:request];
}
}
- (void)viewDidLoad {
[super viewDidLoad];
[activity startAnimating];
self.title = @"iPreacher";
UIBarButtonItem *sharing = [[UIBarButtonItem alloc] initWithTitle:@"Sharing Settings" style:UIBarButtonItemStylePlain target:self action:@selector(gotosettings)];
self.navigationItem.rightBarButtonItem = sharing;
//
// Create a header view. Wrap it in a container to allow us to position
// it better.
//
[self refresh];
}
-(void)gotosettings {
SettingsViewController *dvController = [[SettingsViewController alloc] initWithNibName:@"SettingsViewController" bundle:[NSBundle mainBundle]];
[self.navigationController pushViewController:dvController animated:YES];
}
-(void) refreshInvoked:(id)sender forState:(UIControlState)state {
// Refresh table here...
[_allEntries removeAllObjects];
[self refresh];
}
- (void)parseRss:(GDataXMLElement *)rootElement entries:(NSMutableArray *)entries {
NSArray *channels = [rootElement elementsForName:@"channel"];
for (GDataXMLElement *channel in channels) {
NSString *blogTitle = [channel valueForChild:@"title"];
NSArray *items = [channel elementsForName:@"item"];
for (GDataXMLElement *item in items) {
NSString *articleTitle = [item valueForChild:@"title"];
NSString *articleUrl = [item valueForChild:@"link"];
NSString *articleDateString = [item valueForChild:@"pubDate"];
NSDate *articleDate = [NSDate dateFromInternetDateTimeString:articleDateString formatHint:DateFormatHintRFC822];
NSString *articleImage = [item valueForChild:@"content:encoded"];
NSScanner *theScanner;
NSString *gt =nil;
theScanner = [NSScanner scannerWithString:articleImage];
// find start of tag
[theScanner scanUpToString:@"alt=\"\" width=" intoString:NULL] ;
// find end of tag
[theScanner scanUpToString:@"/>" intoString:>] ;
// replace the found tag with a space
//(you can filter multi-spaces out later if you wish)
NSString *test = [articleImage stringByReplacingOccurrencesOfString:[ NSString stringWithFormat:@"%@", gt] withString:@"alt=\"\" width=\"device-width\" height=\"150\""];
NSString *comments = [articleUrl stringByAppendingString:@"#respond"];
NSString *commentslink = [NSString stringWithFormat: @"<a href=\"%@\">Leave A Comment</a>",comments];
NSString *final = [test stringByReplacingOccurrencesOfString:@"float:none;height:30px" withString:@"float:none;height:1px"];
NSDateFormatter * dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
[dateFormatter setTimeStyle:NSDateFormatterShortStyle];
[dateFormatter setDateStyle:NSDateFormatterMediumStyle];
NSString *dateofarticle = [dateFormatter stringFromDate:articleDate];
NSString *bodyoftext = [[[[[[@"<head><style type='text/css'>a > img {pointer-events: none;cursor: default;}</style></head><b><font size=5><div align=\"left\">" stringByAppendingString:articleTitle] stringByAppendingString:@"</font></b><font size=3><p style=\"color:#989898\">"] stringByAppendingString:dateofarticle] stringByAppendingString:@"</div></p>"] stringByAppendingString:final] stringByAppendingString:commentslink];
RSSEntry *entry = [[[RSSEntry alloc] initWithBlogTitle:blogTitle
articleTitle:articleTitle
articleUrl:articleUrl
articleDate:articleDate
articleImage:bodyoftext] autorelease];
[entries addObject:entry];
}
}
}
- (void)parseAtom:(GDataXMLElement *)rootElement entries:(NSMutableArray *)entries {
NSString *blogTitle = [rootElement valueForChild:@"title"];
NSArray *items = [rootElement elementsForName:@"entry"];
for (GDataXMLElement *item in items) {
NSString *articleTitle = [item valueForChild:@"title"];
NSString *articleUrl = [item valueForChild:@"link"];
NSString *articleDateString = [item valueForChild:@"pubDate"];
NSDate *articleDate = [NSDate dateFromInternetDateTimeString:articleDateString formatHint:DateFormatHintRFC822];
NSString *articleImage = [item valueForChild:@"content:encoded"];
NSDateFormatter * dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
[dateFormatter setTimeStyle:NSDateFormatterShortStyle];
[dateFormatter setDateStyle:NSDateFormatterMediumStyle];
NSString *dateofarticle = [dateFormatter stringFromDate:articleDate];
NSString *bodyoftext = [[[[[@"<b><font size=5><div align=\"left\">" stringByAppendingString:articleTitle] stringByAppendingString:@"</font></b><font size=3><p style=\"color:#989898\">"] stringByAppendingString:dateofarticle] stringByAppendingString:@"</div></p>"] stringByAppendingString:articleImage];
RSSEntry *entry = [[[RSSEntry alloc] initWithBlogTitle:blogTitle
articleTitle:articleTitle
articleUrl:articleUrl
articleDate:articleDate
articleImage:bodyoftext] autorelease];
[entries addObject:entry];
}
}
- (void)parseFeed:(GDataXMLElement *)rootElement entries:(NSMutableArray *)entries {
if ([rootElement.name compare:@"rss"] == NSOrderedSame) {
[self parseRss:rootElement entries:entries];
} else if ([rootElement.name compare:@"feed"] == NSOrderedSame) {
[self parseAtom:rootElement entries:entries];
} else {
NSLog(@"Unsupported root element: %@", rootElement.name);
}
}
- (void)requestFinished:(ASIHTTPRequest *)request {
[_queue addOperationWithBlock:^{
NSError *error;
GDataXMLDocument *doc = [[GDataXMLDocument alloc] initWithData:[request responseData]
options:0 error:&error];
if (doc == nil) {
NSLog(@"Failed to parse %@", request.url);
} else {
NSMutableArray *entries = [NSMutableArray array];
[self parseFeed:doc.rootElement entries:entries];
[[NSOperationQueue mainQueue] addOperationWithBlock:^{
for (RSSEntry *entry in entries) {
int insertIdx = [_allEntries indexForInsertingObject:entry sortedUsingBlock:^(id a, id b) {
RSSEntry *entry1 = (RSSEntry *) a;
RSSEntry *entry2 = (RSSEntry *) b;
return [entry1.articleDate compare:entry2.articleDate];
}];
[_allEntries insertObject:entry atIndex:insertIdx];
}
}];
}
}];
}
- (void)requestFailed:(ASIHTTPRequest *)request {
NSError *error = [request error];
NSLog(@"Error: %@", error);
[self refresh];
}
-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {
return 1;
}
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{
return [_allEntries count];
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
static NSString *identifier = @"Cell";
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];
RSSEntry *entry = [_allEntries objectAtIndex:indexPath.row];
NSString *substring = @"http://316apps.com/ipreachersblog/wp";
NSRange textRange = [entry.articleImage rangeOfString:substring];
UIImageView *recipeImageView = (UIImageView *)[cell viewWithTag:100];
if(textRange.location != NSNotFound){
NSString *thearticleImage = entry.articleImage;
NSRegularExpression *expression = [NSRegularExpression regularExpressionWithPattern:@"src=\"([^\"]+)\"" options:NSRegularExpressionCaseInsensitive error:NULL];
NSString *someString = thearticleImage;
NSString *oneurl = [someString substringWithRange:[expression rangeOfFirstMatchInString:someString options:NSMatchingCompleted range:NSMakeRange(0, [someString length])]];
NSString *finalstring = [oneurl stringByReplacingOccurrencesOfString:@"src=\"" withString:@""];
NSString *thefinalstring = [finalstring stringByReplacingOccurrencesOfString:@"\"" withString:@""];
NSDateFormatter * dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
[dateFormatter setTimeZone:[NSTimeZone localTimeZone]];
[dateFormatter setTimeStyle:NSDateFormatterShortStyle];
[dateFormatter setDateStyle:NSDateFormatterShortStyle];
recipeImageView.image = [UIImage imageNamed:thefinalstring];
recipeImageView.backgroundColor = [UIColor clearColor];
}
else {
NSDateFormatter * dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
[dateFormatter setTimeZone:[NSTimeZone localTimeZone]];
[dateFormatter setTimeStyle:NSDateFormatterShortStyle];
[dateFormatter setDateStyle:NSDateFormatterShortStyle];
recipeImageView.image = [UIImage imageNamed:@"icon@2x.png"];
recipeImageView.backgroundColor = [UIColor clearColor];
}
cell.backgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"photo-frame.png"]];
return cell;
}
@end
更新：我在这里上传了我的整个项目。