UITableView 给出空表，不加载数据

Question

当包含我的表的视图是主（第一个）视图时，一切正常。

但是，当它不是第一个视图并且我切换到该视图时，我的表不会加载数据并且我得到一个空表。

使用 NSLog 我可以看出程序没有调用 numberOfRowsInSection 和 cellForRowAtIndexPath。

我已经声明了<UITableViewDataSource, UITableViewDelegate>、IBOutlet UITableview *tableView。它们也在 InterfaceBuilder 中连接。

我尝试使用 viewWillAppear 和 [tableView reloadData] 但这没有帮助。

我是 iPhone 开发的新手，非常感谢您的帮助！

更新：

我尝试了 [tableView reloadData]，但什么也没发生。
除了 dealloc，我不会在任何地方发布 tableView。

这是一些代码：
appDelegate

//
//  tpbAppDelegate.m
//  tpb


#import "listController.h"
#import "tpbAppDelegate.h"
#import "tpbViewController.h"



@implementation tpbAppDelegate

@synthesize window;
@synthesize viewController;
@synthesize navController;
@synthesize toolbar;
@synthesize btnMyLoc;

@synthesize places; //array that holds data from the XML file


- (void)applicationDidFinishLaunching:(UIApplication *)application {    
    //add places into an array that can be used by other views (Table)
    rssList = [[NSMutableArray alloc] initWithCapacity:1];  

    NSString *paths = [[NSBundle mainBundle] resourcePath];
    NSString *xmlFile = [paths stringByAppendingPathComponent:@"tourplay.xml"];

    NSURL *xmlURL = [NSURL fileURLWithPath:xmlFile isDirectory:NO];
    NSLog(@"DATA URL:  %@", xmlURL);

    NSXMLParser *firstParser = [[NSXMLParser alloc] initWithContentsOfURL:xmlURL];
    [firstParser setDelegate:self];
    [firstParser parse];


    // Resize window for toolbar:    

    CGRect frame = viewController.view.frame;
    frame.size.height -= toolbar.frame.size.height;
    viewController.view.frame = frame;

    //[window addSubview:viewController.view];
    navController.viewControllers = [NSArray arrayWithObject:viewController];
    navController.view.frame  = frame;
    [window addSubview:navController.view];
    [window makeKeyAndVisible];
}

- (IBAction)showList:(id)sender{
    //Switch to table view on segment control change
    UISegmentedControl *segmentControl = (UISegmentedControl *)sender;
    NSString *curSelection = [NSString stringWithFormat:@"%d", [segmentControl selectedSegmentIndex]];
    //[segmentControl titleForSegmentAtIndex: [segmentControl selectedSegmentIndex]]];
    NSLog(@"pressed button %@", curSelection);
    if ([curSelection isEqualToString:@"1"]){
        NSLog(@"TABLE SELECTED");
        listController *listTable = [[listController alloc] init];
        [navController pushViewController:listTable animated:YES]; //SWITCH TO TABLE VIEW (listController)
    } else {
        tpbViewController *tpb = [[tpbViewController alloc] init];
        NSLog(@"MAP SELECTED");
        [navController pushViewController:tpb animated:YES];
    }


}
#pragma mark Praser Methods
//Parse XML into an array
- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qualifiedName attributes:(NSDictionary *)attributeDict {
    //NSLog(@"Started parsing");
    if ([elementName compare:@"tour_point"] == NSOrderedSame) {

        [self.places addObject:[[NSDictionary alloc] initWithObjectsAndKeys:
                                //[attributeDict objectForKey:@"tour_point_id"],@"tour_point_id",
                                [attributeDict objectForKey:@"name"],@"name",
                                [attributeDict objectForKey:@"tour_html"],@"tour_html",
                                [attributeDict objectForKey:@"audio_src"],@"audio_src",
                                nil]];

    } else if ([elementName compare:@"title"] == NSOrderedSame) {
        titlename = (NSString *)[attributeDict objectForKey:@"titlename"];      
        NSLog(@"Done parsing %@ points", titlename);
    }

}

- (void)parserDidEndDocument:(NSXMLParser *)parser {
    NSLog(@"Parser end");

    [parser release];

}

- (void)dealloc {
    [viewController release];
[rssList release];
    [places release];
    [toolbar release];
    [window release];
    [super dealloc];
}


@end

listController.h - 表类

#import <UIKit/UIKit.h>


@interface listController : UIViewController <UITableViewDataSource, UITableViewDelegate> {
    UITableView *tableView;
    NSMutableArray *places;
    NSString *titlename;
}
@property (nonatomic, retain) IBOutlet UITableView *tableView;

@end

listController.m - 表实现

//
//  listController.m
//  tpb
//

//

#import "listController.h"
#import "tpbAppDelegate.h"


@implementation listController

@synthesize tableView;



// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
//- (void)viewWillAppear {


    tpbAppDelegate *delegate = (tpbAppDelegate *)[[UIApplication sharedApplication] delegate];
    places = delegate.places;
    NSLog(@"Loaded table view");
      [super viewDidLoad];
//  [tableView reloadSectionIndexTitles];


}

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tv {
    NSLog(@"Number of secions");
    return 1;
}


- (NSInteger)tableView:(UITableView *)tv numberOfRowsInSection:(NSInteger)section {
    NSLog(@"GETTING COUNT");


    return [places count];

}

- (UITableViewCell *)tableView:(UITableView *)tv cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    NSLog(@"Assigning Cells");
    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tv dequeueReusableCellWithIdentifier:CellIdentifier];
    if (nil == cell) {
        cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:CellIdentifier] autorelease];
    }


    cell.textLabel.text = [[places objectAtIndex:indexPath.row] objectForKey:@"name"];
    //NSLog(@"count %@", [[places objectAtIndex:indexPath.row] objectForKey:@"name"]);
    //cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;

    return cell;
}

- (void)tableView:(UITableView *)tv didSelectRowAtIndexPath:(NSIndexPath *)indexPath {  
    NSLog(@"ROW clicked");
    [tv deselectRowAtIndexPath:indexPath animated:YES];

}




- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];


}

- (void)viewDidUnload {
    NSLog(@"Unloaded tableview");

}


- (void)dealloc {
    [tableView release];
    [places release];
    [super dealloc];
}


@end

-- 到目前为止，我知道 viewDidLoad 加载了，但是没有调用诸如 cellRowAtIndexPath 之类的表格方法。

Answer 1

当您没有将数据源和表视图的委托链接到界面构建器中的文件所有者时，会发生此问题。在界面构建器中再次进行交叉检查，发现数据源和 tableview 委托的连接与文件所有者正确建立，并且您没有错误地将它们与视图链接。

除了告诉一件事，如果

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView

正在被调用。如果是，那么你已经通过了 0。 iphone-sdk-3.0 及更高版本不接受“0”。

谢谢，

马杜普

Answer 2

- (IBAction)showList:(id)sender{
    //Switch to table view on segment control change
    UISegmentedControl *segmentControl = (UISegmentedControl *)sender;
    NSString *curSelection = [NSString stringWithFormat:@"%d", [segmentControl selectedSegmentIndex]];
    //[segmentControl titleForSegmentAtIndex: [segmentControl selectedSegmentIndex]]];
    NSLog(@"pressed button %@", curSelection);
    if ([curSelection isEqualToString:@"1"]){
        NSLog(@"TABLE SELECTED");
        listController *listTable = [[listController alloc] init];

   //Try this
   listTable.places = self.places; // set the array contents here and check

        [navController pushViewController:listTable animated:YES]; //SWITCH TO TABLE VIEW (listController)
    } else {
        tpbViewController *tpb = [[tpbViewController alloc] init];
        NSLog(@"MAP SELECTED");
        [navController pushViewController:tpb animated:YES];
    }
}

不要忘记在 ListController 中为 places 数组编写访问器。让我知道会发生什么。

Answer 3

当你去显示你的tableview时，调用它的reloadData方法；如果您的数据源/委托被分配给正确的对象，那么这将触发表格视图向数据源/委托询问其单元格，并且它应该在该点显示。