我一直在尝试解析XML文件，以便使用后台获取从网站上获取文章。
有人给了我这个问题的答案here。
然而，他的回答导致了SIGABRT错误。
有人可以查看我的代码，看看我的问题是什么？提前谢谢。
我的代码：
NewsViewController.h（此文件加载一个运行后台获取的uitableview来获取文章）：
#import <UIKit/UIKit.h>
@interface NewsViewController : UIViewController<UITableViewDelegate, UITableViewDataSource>
@property (weak, nonatomic) IBOutlet UITableView *tblNews;
- (IBAction)removeDataFile:(id)sender;
-(void)fetchNewDataWithCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler;
@end
NewsViewController.m：
#import "NewsViewController.h"
#define NewsFeed @"http://www.teamfortress.com/rss.xml"
#import "XMLParser.h"
@interface NewsViewController ()
@property (nonatomic, strong) UIRefreshControl *refreshControl;
@property (nonatomic, strong) NSArray *arrNewsData;
@property (nonatomic, strong) NSString *dataFilePath;
-(void)refreshData;
-(void)performNewFetchedDataActionsWithDataArray:(NSArray *)dataArray;
@end
@implementation NewsViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// 1. Make self the delegate and datasource of the table view.
[self.tblNews setDelegate:self];
[self.tblNews setDataSource:self];
// 2. Specify the data storage file path.
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *docDirectory = [paths objectAtIndex:0];
self.dataFilePath = [docDirectory stringByAppendingPathComponent:@"newsdata"];
// 3. Initialize the refresh control.
self.refreshControl = [[UIRefreshControl alloc] init];
[self.refreshControl addTarget:self
action:@selector(refreshData)
forControlEvents:UIControlEventValueChanged];
[self.tblNews addSubview:self.refreshControl];
// 4. Load any saved data.
if ([[NSFileManager defaultManager] fileExistsAtPath:self.dataFilePath]) {
self.arrNewsData = [[NSMutableArray alloc] initWithContentsOfFile:self.dataFilePath];
[self.tblNews reloadData];
}
}
- (IBAction)removeDataFile:(id)sender {
if ([[NSFileManager defaultManager] fileExistsAtPath:self.dataFilePath]) {
[[NSFileManager defaultManager] removeItemAtPath:self.dataFilePath error:nil];
self.arrNewsData = nil;
[self.tblNews reloadData];
}
}
-(void)refreshData{
XMLParser *xmlParser = [[XMLParser alloc] initWithXMLURLString:NewsFeed];
[xmlParser startParsingWithCompletionHandler:^(BOOL success, NSArray *dataArray, NSError *error) {
if (success) {
[self performNewFetchedDataActionsWithDataArray:dataArray];
[self.refreshControl endRefreshing];
}
else{
NSLog(@"%@", [error localizedDescription]);
}
}];
}
-(void)performNewFetchedDataActionsWithDataArray:(NSArray *)dataArray{
// 1. Initialize the arrNewsData array with the parsed data array.
if (self.arrNewsData != nil) {
self.arrNewsData = nil;
}
self.arrNewsData = [[NSArray alloc] initWithArray:dataArray];
// 2. Reload the table view.
[self.tblNews reloadData];
// 3. Save the data permanently to file.
if (![self.arrNewsData writeToFile:self.dataFilePath atomically:YES]) {
NSLog(@"Couldn't save data.");
}
}
-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView{
return 1;
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
return self.arrNewsData.count;
}
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"idCellNewsTitle"];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:@"idCellNewsTitle"];
}
NSDictionary *dict = [self.arrNewsData objectAtIndex:indexPath.row];
cell.textLabel.text = [dict objectForKey:@"title"];
cell.detailTextLabel.text = [dict objectForKey:@"pubDate"];
return cell;
}
-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{
return 80.0;
}
- (void)tableView:(UITableView *)tableView didDeselectRowAtIndexPath:(NSIndexPath *)indexPath{
}
- (void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
if([segue.identifier isEqualToString:@"detail"]){
DetailViewController *detail = segue.destinationViewController;
NSIndexPath *indexPath = [self.tblNews indexPathForSelectedRow];
detail.item = [self.arrNewsData objectAtIndex:indexPath.row];
}
}
-(void)fetchNewDataWithCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler{
XMLParser *xmlParser = [[XMLParser alloc] initWithXMLURLString:NewsFeed];
[xmlParser startParsingWithCompletionHandler:^(BOOL success, NSArray *dataArray, NSError *error) {
if (success) {
NSDictionary *latestDataDict = [dataArray objectAtIndex:0];
NSString *latestTitle = [latestDataDict objectForKey:@"title"];
NSDictionary *existingDataDict = [self.arrNewsData objectAtIndex:0];
NSString *existingTitle = [existingDataDict objectForKey:@"title"];
if ([latestTitle isEqualToString:existingTitle]) {
completionHandler(UIBackgroundFetchResultNoData);
NSLog(@"No new data found.");
}
else{
[self performNewFetchedDataActionsWithDataArray:dataArray];
completionHandler(UIBackgroundFetchResultNewData);
NSLog(@"New data was fetched.");
}
}
else{
completionHandler(UIBackgroundFetchResultFailed);
NSLog(@"Failed to fetch new data.");
}
}];
}
@end
XMLParser.h（此文件解析XML以获取标题，发布日期，链接等）
#import <Foundation/Foundation.h>
@interface XMLParser : NSObject <NSXMLParserDelegate> {
NSMutableDictionary *item;
NSMutableString * currentLink;
}
@property (retain, nonatomic) NSMutableString *currentLink;
-(id)initWithXMLURLString:(NSString *)xmlUrlString;
-(void)startParsingWithCompletionHandler:(void(^)(BOOL success, NSArray *dataArray, NSError *error))completionHandler;
@end
XMLParser.m：
#import "XMLParser.h"
@interface XMLParser()
@property (nonatomic, strong) NSXMLParser *xmlParser;
@property (nonatomic, strong) NSOperationQueue *operationQueue;
@property (nonatomic, strong) NSMutableArray *arrParsedData;
@property (nonatomic, strong) NSString *currentElement;
@property (nonatomic, strong) NSString *newsTitle;
@property (nonatomic, strong) NSString *newsPubDate;
@property (nonatomic, strong) NSString *newsLink;
@property (nonatomic, strong) void (^completionHandler)(BOOL, NSArray *, NSError *);
@property (nonatomic) BOOL isNewsItem;
@property (nonatomic) BOOL allowedData;
-(void)parse;
-(void)endParsingWithError:(NSError *)error;
@end
@implementation XMLParser
-(id)initWithXMLURLString:(NSString *)xmlUrlString{
self = [super init];
if (self) {
self.xmlParser = [[NSXMLParser alloc] initWithContentsOfURL:[NSURL URLWithString:xmlUrlString]];
self.xmlParser.delegate = self;
self.operationQueue = [NSOperationQueue new];
self.currentElement = @"";
self.isNewsItem = NO;
self.allowedData = NO;
}
return self;
}
#pragma mark - Public method implementation
-(void)startParsingWithCompletionHandler:(void (^)(BOOL, NSArray *, NSError *))completionHandler{
self.completionHandler = completionHandler;
NSInvocationOperation *operation = [[NSInvocationOperation alloc] initWithTarget:self
selector:@selector(parse)
object:nil];
[self.operationQueue addOperation:operation];
}
#pragma mark - Private method implementation
-(void)parse{
if (self.xmlParser != nil) {
[self.xmlParser parse];
}
}
-(void)endParsingWithError:(NSError *)error{
BOOL success = (error == nil) ? YES : NO;
self.completionHandler(success, self.arrParsedData, error);
}
#pragma mark - NSXMLParserDelegate method implementation
-(void)parserDidStartDocument:(NSXMLParser *)parser{
if (self.arrParsedData != nil) {
[self.arrParsedData removeAllObjects];
self.arrParsedData = nil;
}
self.arrParsedData = [[NSMutableArray alloc] init];
}
-(void)parserDidEndDocument:(NSXMLParser *)parser{
[self performSelectorOnMainThread:@selector(endParsingWithError:) withObject:nil waitUntilDone:NO];
}
-(void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict{
if ([elementName isEqualToString:@"item"]) {
item = [[NSMutableDictionary alloc] init];
self.currentLink = [[NSMutableString alloc] init];
self.isNewsItem = YES;
}
if (self.isNewsItem) {
if ([elementName isEqualToString:@"title"] ||
[elementName isEqualToString:@"pubDate"] ||
[elementName isEqualToString:@"link"]) {
self.allowedData = YES;
}
}
self.currentElement = elementName;
}
-(void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName{
if ([elementName isEqualToString:@"item"]) {
self.isNewsItem = NO;
[item setObject:self.currentLink forKey:@"link"];
NSDictionary *dict = @{@"title": self.newsTitle,
@"pubDate": self.newsPubDate,
@"link": self.newsLink
};
[self.arrParsedData addObject:dict];
}
if (self.isNewsItem) {
if ([elementName isEqualToString:@"title"] ||
[elementName isEqualToString:@"pubDate"] ||
[elementName isEqualToString:@"link"]) {
self.allowedData = NO;
}
}
}
-(void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string{
if (self.allowedData) {
if ([self.currentElement isEqualToString:@"title"]) {
self.newsTitle = string;
}
else if ([self.currentElement isEqualToString:@"pubDate"]){
self.newsPubDate = string;
}
else if ([self.currentElement isEqualToString:@"link"]){
self.newsLink = string;
[self.currentLink appendString:string];
}
}
}
-(void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError{
[self performSelectorOnMainThread:@selector(endParsingWithError:) withObject:parseError waitUntilDone:NO];
}
-(void)parser:(NSXMLParser *)parser validationErrorOccurred:(NSError *)validationError{
[self performSelectorOnMainThread:@selector(endParsingWithError:) withObject:validationError waitUntilDone:NO];
}
@end
DetailViewController.h（这是包含我的UIWebView的uiviewcontroller的文件）：
#import <UIKit/UIKit.h>
@interface DetailViewController : UIViewController<UIWebViewDelegate> {
NSDictionary *item;
}
@property (retain, nonatomic) NSDictionary *item;
@property (retain, nonatomic) IBOutlet UIWebView *itemSummary;
@end
DetailViewController.m：
#import "DetailViewController.h"
@interface DetailViewController ()
@end
@implementation DetailViewController
@synthesize item;
@synthesize itemSummary = _itemSummary;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
_itemSummary.delegate = self;
_itemSummary.scalesPageToFit = YES;
NSURL* url = [NSURL URLWithString:[item objectForKey:@"link"]];
[_itemSummary loadRequest:[NSURLRequest requestWithURL:url]];
// Do any additional setup after loading the view.
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
/*
#pragma mark - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
}
*/
@end
如果您想自己运行该项目，可以在Github上找到它here
注意使用链接时，Xcode项目位于“您的TF2指南”下。
感谢任何有帮助的人！
CRASH LOG
2014-04-08 16:33:05.611 Your Guide to TF2[499:70b] -[UINavigationController fetchNewDataWithCompletionHandler:]: unrecognized selector sent to instance 0x1090aa930
2014-04-08 16:33:05.755 Your Guide to TF2[499:70b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UINavigationController fetchNewDataWithCompletionHandler:]: unrecognized selector sent to instance 0x1090aa930'
*** First throw call stack:
(
0 CoreFoundation 0x000000010189a795 __exceptionPreprocess + 165
1 libobjc.A.dylib 0x00000001015fd991 objc_exception_throw + 43
2 CoreFoundation 0x000000010192bbad -[NSObject(NSObject) doesNotRecognizeSelector:] + 205
3 CoreFoundation 0x000000010188c09d ___forwarding___ + 973
4 CoreFoundation 0x000000010188bc48 _CF_forwarding_prep_0 + 120
5 Your Guide to TF2 0x0000000100004819 -[AppDelegate application:performFetchWithCompletionHandler:] + 345
6 UIKit 0x000000010026e0b5 -[UIApplication _handleOpportunisticFetchWithSequenceNumber:] + 170
7 UIKit 0x000000010025b200 -[UIApplication _callInitializationDelegatesForURL:payload:suspended:] + 1761
8 UIKit 0x000000010025ebe8 -[UIApplication _runWithURL:payload:launchOrientation:statusBarStyle:statusBarHidden:] + 660
9 UIKit 0x000000010026faab -[UIApplication handleEvent:withNewEvent:] + 3092
10 UIKit 0x000000010026ff1e -[UIApplication sendEvent:] + 79
11 UIKit 0x00000001002602be _UIApplicationHandleEvent + 618
12 GraphicsServices 0x00000001039a2bb6 _PurpleEventCallback + 762
13 GraphicsServices 0x00000001039a267d PurpleEventCallback + 35
14 CoreFoundation 0x000000010181c819 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 41
15 CoreFoundation 0x000000010181c5ee __CFRunLoopDoSource1 + 478
16 CoreFoundation 0x0000000101845ab3 __CFRunLoopRun + 1939
17 CoreFoundation 0x0000000101844f33 CFRunLoopRunSpecific + 467
18 UIKit 0x000000010025e4bd -[UIApplication _run] + 609
19 UIKit 0x0000000100260043 UIApplicationMain + 1010
20 Your Guide to TF2 0x0000000100004ce3 main + 115
21 libdyld.dylib 0x0000000101f295fd start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)
AppDelegate.m
#import "AppDelegate.h"
#import "NewsViewController.h"
#define UIColorFromRGB(rgbValue) [UIColor colorWithRed:((float)((rgbValue & 0xFF0000) >> 16))/255.0 green:((float)((rgbValue & 0xFF00) >> 8))/255.0 blue:((float)(rgbValue & 0xFF))/255.0 alpha:1.0]
@implementation AppDelegate
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
[application setMinimumBackgroundFetchInterval:UIApplicationBackgroundFetchIntervalMinimum];
// Override point for customization after application launch.
// Uncomment to change the background color of navigation bar
[[UINavigationBar appearance] setBarTintColor:UIColorFromRGB(0xb35326)];
// Uncomment to change the color of back button
//[[UINavigationBar appearance] setTintColor:[UIColor whiteColor]];
// Uncomment to assign a custom backgroung image
//[[UINavigationBar appearance] setBackgroundImage:[UIImage imageNamed:@"tf2_logo.png"] forBarMetrics:UIBarMetricsDefault];
// Uncomment to change the back indicator image
/*
[[UINavigationBar appearance] setBackIndicatorImage:[UIImage imageNamed:@"back_btn.png"]];
[[UINavigationBar appearance] setBackIndicatorTransitionMaskImage:[UIImage imageNamed:@"back_btn.png"]];
*/
// Uncomment to change the font style of the title
/*
NSShadow *shadow = [[NSShadow alloc] init];
shadow.shadowColor = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.8];
shadow.shadowOffset = CGSizeMake(0, 1);
[[UINavigationBar appearance] setTitleTextAttributes: [NSDictionary dictionaryWithObjectsAndKeys:
[UIColor colorWithRed:245.0/255.0 green:245.0/255.0 blue:245.0/255.0 alpha:1.0], NSForegroundColorAttributeName,
shadow, NSShadowAttributeName,
[UIFont fontWithName:@"HelveticaNeue-CondensedBlack" size:21.0], NSFontAttributeName, nil]];
*/
return YES;
}
-(void)application:(UIApplication *)application performFetchWithCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler{
NSDate *fetchStart = [NSDate date];
NewsViewController *viewController = (NewsViewController *)self.window.rootViewController;
[viewController fetchNewDataWithCompletionHandler:^(UIBackgroundFetchResult result) {
completionHandler(result);
NSDate *fetchEnd = [NSDate date];
NSTimeInterval timeElapsed = [fetchEnd timeIntervalSinceDate:fetchStart];
NSLog(@"Background Fetch Duration: %f seconds", timeElapsed);
}];
}
答案 0 :(得分：1)
问题出在-[AppDelegate application:performFetchWithCompletionHandler:]
这条线错了：
NewsViewController *viewController = (NewsViewController *)self.window.rootViewController;
根视图控制器是UINavigationController，但您假设它是NewsViewController。那应该是：
UINavigationController *navController = (UINavigationController *)self.window.rootViewController;
NewsViewController *viewController = (NewsViewController *)[[navController viewControllers] objectAtIndex:0];
答案 1 :(得分：1)
好的..再看看你的代码。
缺少一些东西。
在NewsViewController.h中
@interface NewsViewController : UIViewController<UITableViewDelegate, UITableViewDataSource>{
NSArray *items;
NSMutableArray *itemArray;
}
需要包含Array和MutableArray
还在NewsViewController.h中添加属性
@property (retain, nonatomic) NSArray *items;
@property (retain, nonatomic) NSMutableArray *itemArray;
在您的实施文件中。
@synthesize items, itemArray;
在XMLParser实现中
@synthesize currentLink;
最后在你的故事板上，你有来自视图控制器而不是单元格行的segue。
删除当前的segue，并将另一个来自单元格的视图添加到DetailViewController视图中。
我也推动了这些变化。