objective-c - 使用 StoryBoard 在 Segue 中传递信息

Question

我已经涉足 iOS 应用程序有一段时间了，并没有真正花太多时间来投资它。我现在正用头撞墙，因为我不知道如何让它工作或我没有正确配置什么......我试图让 NewsTableViewController 中引用的正文加载到 NewsView 上的 textView控制器。目前只有标题更新，文本视图只显示 lorum ipsum 文本。

我的理解是，因为我可以在 NSLog 中看到信息，并且如果我尝试将新闻正文文本放在推送视图的标题中，它会显示在标题中 - 我的想法是我未能定义视图，但正如我所说我就是看不到！无论如何，这就是我所拥有的......

这是将数据从 xml 文件加载到第一个视图的表

//
//  NewsTableViewController.h
//

#import <UIKit/UIKit.h>
#import "MBProgressHUD.h"

@interface NewsTableViewController : UITableViewController
{
    IBOutlet UITableView *newsTable;
    CGSize cellSize;
    NSXMLParser *rssParser;
    NSMutableArray *stories;
    NSMutableDictionary *item;
    NSString *currentElement;
    NSMutableString *currentName, *currentTitle, *currentDated, *currentBodyText;
}

- (UITableViewCell *) getCellContentView:(NSString *)MyIdentifier;

@end

代码的实现

//
//  NewsTableViewController.m
//  

#import "NewsTableViewController.h"
#import "NewsViewController.h"

@interface NewsTableViewController ()

@end

@implementation NewsTableViewController


dispatch_queue_t myQueue;

-(void) showHUD{

    MBProgressHUD *HUD;

    HUD = [[MBProgressHUD alloc] initWithView:self.navigationController.view];
    [self.navigationController.view addSubview:HUD];

    //HUD.delegate = self;
    HUD.labelText = @"News Loading";
    HUD.detailsLabelText = @"please wait...";
    HUD.square = YES;
    HUD.dimBackground = YES;

    [HUD showWhileExecuting:@selector(parserStart) onTarget:self withObject:nil animated:YES];
    //dispatch_async(dispatch_get_main_queue(), ^ {[self parserStart]; });   

}

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


- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    //NSLog(@"View Did Appear");


    myQueue = dispatch_queue_create("com.xxxxxxxxxxx.xxxxxxxxxx",NULL);
    dispatch_async(dispatch_get_main_queue(), ^ {[self showHUD]; });

}


- (void) parserStart {
    //Insert a small delay for testing purposes
    //[NSThread sleepForTimeInterval:2];

    if ([stories count] == 0) {


        NSString *path = @"http://xxx.xxxxxxxxxxx.xxx/xxxxxx/xxxxxxx.xml";
        [self parseXMLFileAtURL:path];
        //[path release];
    }
    cellSize = CGSizeMake([newsTable bounds].size.width, 60);


    [self.tableView reloadData];


}


- (void)parseXMLFileAtURL:(NSString *)URL {

    if (stories) {
        //[stories release];
        stories = nil;
    }

    stories = [[NSMutableArray alloc] init];

    //you must then convert the path to a proper NSURL or it won't work
    NSURL *xmlURL = [NSURL URLWithString:URL];

    // here, for some reason you have to use NSClassFromString when trying to alloc NSXMLParser, otherwise you will get an object not found error
    // this may be necessary only for the toolchain
    rssParser = [[NSXMLParser alloc] initWithContentsOfURL:xmlURL];

    // Set self as the delegate of the parser so that it will receive the parser delegate methods callbacks.
    [rssParser setDelegate:self];

    // Depending on the XML document you're parsing, you may want to enable these features of NSXMLParser.
    [rssParser setShouldProcessNamespaces:NO];
    [rssParser setShouldReportNamespacePrefixes:NO];
    [rssParser setShouldResolveExternalEntities:NO];

    [rssParser parse];
}


- (void)parserDidStartDocument:(NSXMLParser *)parser {
    //NSLog(@"found file and started parsing");
}

- (void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError {
    NSString * errorString = [NSString stringWithFormat:@"Unable to download the news feed from web site (Error code %i )", [parseError code]];
    //NSLog(@"error parsing XML: %@", errorString);

    UIAlertView * errorAlert = [[UIAlertView alloc] initWithTitle:@"Error loading content" message:errorString delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
    [errorAlert show];
}

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict{
    //NSLog(@"found this element: %@", elementName);

    //if (currentElement) {
        //[currentElement release]; 
        //currentElement = nil; 
    //}

    currentElement = [elementName copy];

    if ([elementName isEqualToString:@"article"]) {
        // clear out our story item caches...
        item = [[NSMutableDictionary alloc] init];
        currentName = [[NSMutableString alloc] init];
        currentTitle = [[NSMutableString alloc] init];
        currentDated = [[NSMutableString alloc] init];
        currentBodyText = [[NSMutableString alloc] init];
    }
}


- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string{
    //NSLog(@"found characters: %@", string);
    // save the characters for the current item...
    if ([currentElement isEqualToString:@"article"]) {
        [currentName appendString:string];
    } else if ([currentElement isEqualToString:@"title"]) {
        [currentTitle appendString:string];
    } else if ([currentElement isEqualToString:@"dated"]) {
        [currentDated appendString:string];
    } else if ([currentElement isEqualToString:@"bodytext"]) {
        [currentBodyText appendString:string];
    }
}


- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName{

    //NSLog(@"ended element: %@", elementName);
    if ([elementName isEqualToString:@"article"]) {
        // save values to an item, then store that item into the array...
        [item setObject:currentName forKey:@"article"];
        [item setObject:currentTitle forKey:@"title"];
        [item setObject:currentDated forKey:@"dated"];
        [item setObject:currentBodyText forKey:@"bodytext"];

        [stories addObject:[item copy]];
        //NSLog(@"adding story: %@", currentName);
    }
}


- (void)parserDidEndDocument:(NSXMLParser *)parser {

}


- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.
}

- (void)viewDidUnload {
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;

}



#pragma mark Table view methods

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


// Customize the number of rows in the table view.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return [stories count];
}


// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    static NSString *MyIdentifier = @"MyIdentifier";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:MyIdentifier];


    if (cell == nil)

        cell = [self getCellContentView:MyIdentifier];

    cell.selectionStyle = UITableViewCellSelectionStyleNone;

    UILabel *lblTitle = (UILabel *)[cell viewWithTag:101];
    UILabel *lblDate = (UILabel *)[cell viewWithTag:102];
    UILabel *lblBodyText = (UILabel *)[cell viewWithTag:103];

    int storyIndex = [indexPath indexAtPosition: [indexPath length] - 1];

    //NSString *articleValue = [[stories objectAtIndex: storyIndex] objectForKey: @"article"];
    NSString *titleValue = [[stories objectAtIndex: storyIndex] objectForKey: @"title"];
    NSString *datedValue = [[stories objectAtIndex: storyIndex] objectForKey: @"dated"];
    NSString *bodytextValue = [[stories objectAtIndex: storyIndex] objectForKey: @"bodytext"];

    lblTitle.text = titleValue;
    lblDate.text = datedValue;
    lblBodyText.text = bodytextValue;

    cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;

    return cell;
}


- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([segue.identifier isEqualToString:@"NewsSegue"]) {

        // note that "sender" will be the tableView cell that was selected
        UITableViewCell *cell = (UITableViewCell*)sender;
        NSIndexPath *indexPath = [self.tableView indexPathForCell:cell];

        NewsViewController *nvc = [segue destinationViewController];

        int storyIndex = [indexPath indexAtPosition: [indexPath length] - 1];

        nvc.title = [[stories objectAtIndex: storyIndex] objectForKey: @"title"];
        nvc.textView.text = [[stories objectAtIndex: storyIndex] objectForKey: @"bodytext"];
        //nvc.textView.text = [self getDataToPass:storyIndex.row];


        // hide the tabBar Controller
        nvc.hidesBottomBarWhenPushed = YES;

        //NSLog(@"Article : %@", [[stories objectAtIndex:storyIndex] objectForKey: @"article"]);
        NSLog(@"Title : %@", [[stories objectAtIndex:storyIndex] objectForKey: @"title"]);
        NSLog(@"Dated : %@", [[stories objectAtIndex:storyIndex] objectForKey: @"dated"]);
        NSLog(@"BodyText : %@", [[stories objectAtIndex:storyIndex] objectForKey: @"bodytext"]);    }
}

- (void)dealloc {
}

@end

现在我正在推进的观点......

//
//  NewsViewController.h
//

#import <UIKit/UIKit.h>

@class NewsViewController;

@interface NewsViewController : UIViewController {

    IBOutlet UITextView* textView;
}

@property (nonatomic, retain) IBOutlet UITextView* textView;

@end

然后是这个视图的实现文件。

//
//  NewsViewController.m
//

#import "NewsViewController.h"
#import "NewsTableViewController.h"

@interface NewsViewController ()

@end

@implementation NewsViewController

@synthesize textView;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.textView = self.title;
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
}

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

@end

在此处输入图像描述

编辑：据我了解，Segue 的这一部分是我从附加到解析器的代码的发送部分发送信息的地方：

    nvc.title = [[stories objectAtIndex: storyIndex] objectForKey: @"title"];
    nvc.textView.text = [[stories objectAtIndex:storyIndex] objectForKey: @"bodytext"];

如果我将正文设置为信息显示的标题，那么为什么我认为 textview 有一些不正确的地方，这就是我被卡住的地方吗？

任何帮助将不胜感激，因为我真的不知道出了什么问题！！！我实际上希望我错过了什么非常明显！感谢您的关注。

score 1 · Accepted Answer

我在prepareforsegue中添加了以下内容

[nvc setTextFieldContentText:[[stories objectAtIndex:storyIndex] objectForKey: @"bodytext"]];

然后在视图中确实加载了接收视图

[textView setText:[self textFieldContentText]];

并且显然在接收视图头文件中设置属性

@property NSString* textFieldContentText;

感谢所有花时间寻找和帮助的人。

score 0 · Accepted Answer

0

需要设置 textView 的 text 属性。试试这个：

self.textView.text = self.title;

于 2013-01-28T11:15:48.540 回答

score 0 · Accepted Answer

我有点困惑这行代码试图完成什么：self.textView = self.title;

但无论如何，我认为您的问题是您正在尝试为尚不存在的视图设置文本。尝试在您的新闻视图控制器中创建一个NSString（比如说）并将其设置在您的然后在您的或做textViewStringprepareForSegueviewDidLoadviewWillAppearself.textView.text = self.textViewString;

objective-c - 使用 StoryBoard 在 Segue 中传递信息

3 回答 3

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