ios - 将 JSON 字符串从一个 View 传递到另一个 View

Question

我有一个 TableView ，我在其中解析一些 JSON 数据并将其显示在自定义单元格中。在一个 View 中，我正在解析来自 Facebook 的特定用户的帖子。

我在 TableView 中显示预览，但我想将数据传递到另一个 View 。例如，我在表格 View 中阅读了一篇文章的预览，但我想阅读整篇文章。

当我单击该帖子(单元格)时，我应该被定向到一个新的 View Controller ，其中显示完整的帖子(在标签或 TextView 中)。

我该怎么做？

这是我将数据解析到 TableView 的代码:

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.


    strURLToLoad = [[NSMutableString alloc] init];

    [btnFaceBook setTitle:@"link.com/json.php?name=Name" forState:UIControlStateDisabled];
    [btnTwitter setTitle:@"link1.com/json.php?name=Name" forState:UIControlStateDisabled];
    [btnTwitter2 setTitle:@"link2.com/json.php?name=Name" forState:UIControlStateDisabled];

    [btnFaceBook setBackgroundImage:[UIImage imageNamed:@"tab_selected.png"] forState:UIControlStateNormal];
    [btnFaceBook setBackgroundImage:[UIImage imageNamed:@"tab_unselected.png"] forState:UIControlStateSelected];

    [btnTwitter setBackgroundImage:[UIImage imageNamed:@"tab_selected.png"] forState:UIControlStateNormal];
    [btnTwitter setBackgroundImage:[UIImage imageNamed:@"tab_unselected.png"] forState:UIControlStateSelected];

    [btnTwitter2 setBackgroundImage:[UIImage imageNamed:@"tab_selected.png"] forState:UIControlStateNormal];
    [btnTwitter2 setBackgroundImage:[UIImage imageNamed:@"tab_unselected.png"] forState:UIControlStateSelected];



    NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"PostsObject" owner:self options:nil];
    PostsObject *cell = [nib objectAtIndex:0];
    fontForCellText = cell.title.font;
    cellTextWidth = cell.title.frame.size.width;
    cellHeightExceptText = cell.frame.size.height - cell.title.frame.size.height;

    [self.navigationController setNavigationBarHidden:YES];

    self.tableView.separatorColor = [UIColor clearColor];

    // Setting Up Activity Indicator View
    self.activityIndicatorView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
    self.activityIndicatorView.hidesWhenStopped = YES;
    self.activityIndicatorView.center = self.view.center;
    [self.view addSubview:self.activityIndicatorView];
    [self.activityIndicatorView startAnimating];
    self.tableView.separatorColor = [UIColor clearColor];

    // Initializing Data Source
    movies = [[NSMutableArray alloc] init];

    [self btnFromTabBarClicked:btnFaceBook];
}

- (void)loadJSONFromCurrentURL
{
    [self.activityIndicatorView startAnimating];

    NSURLRequest *request = [[NSURLRequest alloc] initWithURL:[NSURL URLWithString:strURLToLoad]];

    AFJSONRequestOperation *operation = [AFJSONRequestOperation JSONRequestOperationWithRequest:request success:^(NSURLRequest *request, NSHTTPURLResponse *response, id JSON) {
        [movies setArray:JSON];
        [self.activityIndicatorView stopAnimating];
        [self.tableView reloadData];

    } failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error, id JSON) {
        NSLog(@"Request Failed with Error: %@, %@", error, error.userInfo);
    }];

    [operation start];
}

- (IBAction)btnFromTabBarClicked:(UIButton *)sender
{
    //Unselect all 3 buttons
    btnFaceBook.selected = btnTwitter.selected = btnTwitter2.selected = NO;

    //Select the button that was clicked
    sender.selected = YES;

    //Set the string of an NSMutableString property called strURLToLoad with the URL
    //The URL is pre stored in the text of the UIButton in the Disabled text.
    [strURLToLoad setString:[sender titleForState:UIControlStateDisabled]];

    //Load the URL
    [self loadJSONFromCurrentURL];
}

// Table View Data Source Methods
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    if (movies && movies.count) {
        return movies.count;
    } else {
        return 0;
    }
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *simpleTableIdentifier = @"PostsObject";

    PostsObject *cell = (PostsObject *)[tableView dequeueReusableCellWithIdentifier:simpleTableIdentifier];
    if (cell == nil)
    {
        NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"PostsObject" owner:self options:nil];
        cell = [nib objectAtIndex:0];
        cell.selectionStyle = UITableViewCellSelectionStyleNone;

    }

    NSDictionary *movie = [self.movies objectAtIndex:indexPath.row];
    NSString *strText = [movie objectForKey:[self getTextKey]];

    CGRect rect = cell.title.frame;
    rect.size.height = [self getHeightForText:strText];
    cell.title.frame = rect;
    cell.title.text = strText;
    cell.arrow.center = CGPointMake(cell.arrow.frame.origin.x, rect.origin.y + rect.size.height/2);
    cell.published.text = [movie objectForKey:@"published"];
    cell.twitterName.text = [movie objectForKey:[self getTwitterName]];
    return cell;
}

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    NSDictionary *movie = [self.movies objectAtIndex:indexPath.row];
    NSString *strText = [movie objectForKey:[self getTextKey]];

    CGFloat cellHeight = cellHeightExceptText + [self getHeightForText:strText];

    return cellHeight;
}

- (NSString *)getTextKey
{
    return btnTwitter.selected?@"tweet":@"message";
}

- (NSString *)getTwitterName
{
    return btnTwitter2.selected?@"user":@"user";
}

- (CGFloat)getHeightForText:(NSString *)strText
{
    CGSize constraintSize = CGSizeMake(cellTextWidth, MAXFLOAT);
    CGSize labelSize = [strText sizeWithFont:fontForCellText constrainedToSize:constraintSize lineBreakMode:NSLineBreakByWordWrapping];
    NSLog(@"labelSize.height = %f",labelSize.height);
    return labelSize.height;
}

Answer 1

有多种方法可以实现这一目标。

您可以实现 tableview:didSelectRowAtIndexPath: 并在其中分配下一个 VC 并将您的数据传递给它的属性，然后呈现该 VC。

或者您可以实现从表格单元格到新 VC 的 segue，然后在 prepareForSegue: 中将数据传递给它的属性。

无论哪种方式，所呈现的 VC 都可以通过 viewDidLoad 将数据加载到该 View 中。

就传递 JSON 而言，它并不是特别理想。您可能会考虑创建自己的基于 Objective-C 的模型对象，JSON 数据将被解析成这些模型对象，然后在您的应用中使用这些模型对象。