关于ios：解析XML文件中的链接并将其推送到UIWebView


Parsing links from XML file and pushing it to a UIWebView

我一直在尝试解析XML文件，以便使用后台抓取从网站获取文章。

此处是教程的链接。

我已经成功完成了本教程并解析了我的XML文件，但是当用户单击文章时，我希望他们在UIWebView中查看它，而不是通过Safari从外部推送链接。

我该如何在我的代码中实现呢？

我的代码：

NewsViewController.h(此文件加载运行后台提取以获取文章的uitableview)：

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 #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：

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 #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;
 }

 //THIS IS THE SECTION OF CODE THAT OPENS THE LINKS

 -(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
     NSDictionary *dict = [self.arrNewsData objectAtIndex:indexPath.row];

     NSString *newsLink = [dict objectForKey:@"link"];

         [[UIApplication sharedApplication] openURL:[NSURL URLWithString:newsLink]];
 }

 //END OF THE SECTION


 -(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)。

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#import <Foundation/Foundation.h>

@interface XMLParser : NSObject <NSXMLParserDelegate>

-(id)initWithXMLURLString:(NSString *)xmlUrlString;
-(void)startParsingWithCompletionHandler:(void(^)(BOOL success, NSArray *dataArray, NSError *error))completionHandler;

@end

XMLParser.m：

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 #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"]) {
         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;


         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;
         }
     }
 }


 -(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

如果您想自己运行项目，可以在Github上找到它

注意使用链接时，Xcode项目在"您的TF2指南"下。

感谢任何有帮助的人！

添加UIViewController，包括UIWebView。更改您的didSelectRowAtIndexPath

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- (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];

    }
}

在您的Detailview头文件中：

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#import <UIKit/UIKit.h>

@interface DetailViewController : UIViewController<UIWebViewDelegate> {
    NSDictionary *item;
}

@property (retain, nonatomic) NSDictionary *item;
@property (retain, nonatomic) IBOutlet UIWebView *itemSummary;

@end

在您的实现中：

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#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

在解析器头中添加NSMutableDictionary和NSMutableStrring：

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@interface XMLParser : NSObject <NSXMLParserDelegate> {
    NSMutableDictionary *item;
    NSMutableString * currentLink;
}

@property (retain, nonatomic) NSMutableString *currentLink;

在您的实现中：

在didStartElement中：

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if ([elementName isEqualToString:@"item"]) {
        item = [[NSMutableDictionary alloc] init];
        self.currentLink = [[NSMutableString alloc] init];
        self.isNewsItem = YES;
    }

在您的didEndElement中：

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if ([elementName isEqualToString:@"item"]) {
        self.isNewsItem = NO;

        [item setObject:self.currentLink forKey:@"link"];

在您找到的字符中：

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else if ([self.currentElement isEqualToString:@"link"]){
            self.newsLink = string;
            [self.currentLink appendString:string];
        }

在情节提要中：
将您的tableviewcontroller嵌入到导航控制器中，将tableview的推推序列添加到详细信息视图，并添加标识符" detail"。

也将更改提交到您的git。

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