数据未在详细视图中加载

Question

我正在尝试将数据加载到详细视图中。任何人都可以看一下并了解为什么它不显示吗？它在我的 rootviewcontroller 中加载得很好，只是在详细视图中加载得不好。

DetailViewController.m

 #import "DetailViewController.h"


@implementation DetailViewController




- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning]; // Releases the view if it doesn't have a superview
    // Release anything that's not essential, such as cached data
}



- (void)setIcon:(UIImage *)newIcon
{
    [super setIcon:newIcon];
    iconView.image = newIcon;
}

- (void)setPublisher:(NSString *)newPublisher
{
    [super setPublisher:newPublisher];
    publisherLabel.text = newPublisher;
}


- (void)setName:(NSString *)newName
{
    [super setName:newName];
    nameLabel.text = newName;
}



- (void)dealloc
{
    [iconView release];
    [publisherLabel release];
    [nameLabel release];
    [priceLabel release];

    [super dealloc];
}


@end

detailviewcontroller.h

 #import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>




@interface DetailViewController : UIViewController {
    IBOutlet UIImageView *iconView;
    IBOutlet UILabel *publisherLabel;
    IBOutlet UILabel *nameLabel;
    IBOutlet UILabel *priceLabel;

}




@end

RootViewControllerPoints.m

#import "RootViewControllerPoints.h"
#import "DetailViewController.h"




#define USE_INDIVIDUAL_SUBVIEWS_CELL    1

#define DARK_BACKGROUND  [UIColor colorWithRed:151.0/255.0 green:152.0/255.0 blue:155.0/255.0 alpha:1.0]
#define LIGHT_BACKGROUND [UIColor colorWithRed:172.0/255.0 green:173.0/255.0 blue:175.0/255.0 alpha:1.0]


@implementation RootViewController

@synthesize tmpCell, data;


#pragma mark View controller methods

- (void)viewDidLoad
{
    [super viewDidLoad];

    // Configure the table view.
    self.tableView.rowHeight = 73.0;
    self.tableView.backgroundColor = DARK_BACKGROUND;
    self.tableView.separatorStyle = UITableViewCellSeparatorStyleNone;

    // Load the data.
    NSString *dataPath = [[NSBundle mainBundle] pathForResource:@"Data" ofType:@"plist"];
    self.data = [NSArray arrayWithContentsOfFile:dataPath];
}


- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation
{
    switch (toInterfaceOrientation) {
        case UIInterfaceOrientationPortrait:
        case UIInterfaceOrientationLandscapeLeft:
        case UIInterfaceOrientationLandscapeRight:
            return YES;
        default:
            return NO;
    }
}



#pragma mark Table view methods

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


- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return [data count];
}


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

    ApplicationCell *cell = (ApplicationCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil) {

#if USE_INDIVIDUAL_SUBVIEWS_CELL
        [[NSBundle mainBundle] loadNibNamed:@"IndividualSubviewsBasedApplicationCell" owner:self options:nil];
        cell = tmpCell;
        self.tmpCell = nil;

#endif
    }

    // Display dark and light background in alternate rows -- see tableView:willDisplayCell:forRowAtIndexPath:.
    cell.useDarkBackground = (indexPath.row % 2 == 0);

    // Configure the data for the cell.

    NSDictionary *dataItem = [data objectAtIndex:indexPath.row];
    cell.icon = [UIImage imageNamed:[dataItem objectForKey:@"Icon"]];
    cell.publisher = [dataItem objectForKey:@"Publisher"];
    cell.name = [dataItem objectForKey:@"Name"];


    cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;

    return cell;
}



- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    DetailViewController *detailViewController = [[DetailViewController alloc] initWithNibName:@"DetailView" bundle:nil];
    detailViewController. = [data objectAtIndex:indexPath.row];
   [self.navigationController pushViewController:detailViewController animated:YES];
    [detailViewController release];
}



@end

这已经困扰我很长一段时间了，我查看了许多示例、教程，甚至询问了其他 iphone 开发人员。所有的来源似乎都在说不同的东西。

Answer 1

第一个问题是 DetailViewController 中的 setXXX 方法尝试调用 super setXXX，但由于 DetailViewController 是 UIViewController 的子类，因此对 super 的调用将失败，因为 UIViewController 没有此类方法。删除 setXXX 方法中对 super 的调用。

第二个问题是 setXXX 方法直接在 DetailViewController 上设置控件，但在加载视图之前控件将无法访问，因此如果在调用 pushViewController 之前调用这些方法，它将不起作用。

如果您按如下方式更改 didSelectRowAtIndexPath 中的代码，它应该可以工作：

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
   DetailViewController *detailViewController = [[DetailViewController alloc] initWithNibName:@"DetailView" bundle:nil];
   [self.navigationController pushViewController:detailViewController animated:YES];
   [detailViewController setName:@"name here"];
   [detailViewController setPublisher:@"publisher here"];
   [detailViewController setIcon:yourImageVariableHere];       
   [detailViewController release];
}

虽然上述更改应该可以工作，但您可能需要考虑创建 ivars 来保存 DetailViewController 中的值（而不是使用 ui 控件本身来保存数据）。然后使用@property和@synthesize为它们创建属性。可以在创建 DetailViewController 后立即设置属性，并且在视图的 viewDidLoad 中，可以将 ui 控件设置为属性值。这将使 DetailViewController 能够更好地控制其 ui 的更新方式，允许您在不影响调用者的情况下更改 ui，并且不需要显示它来设置其属性。