iOS（iPhone / iPad）SDK - 在reloadData上不刷新UITableView（在reloadData上不调用numberOfSectionsInTableView等）

Question

由于某种原因[tView reloadData]（其中tView是UITableView）不刷新我的UITableView。 cellForRowAtIndexPath，numberOfSectionsInTableView和numberOfRowsInSection只能在加载时调用一次。 [tView reloadData]之后似乎没有调用这些方法。这是我的代码：

（AppDelegate.h）：

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

@class FirstNavViewController;
@class SecondTableViewController;

@interface <appname>AppDelegate : NSObject <UIApplicationDelegate, MBProgressHUDDelegate> {
    UIWindow *window;
    UITabBarController *rootController;
    FirstNavViewController *viewController;
    SecondTableViewController *viewController1;
    NSMutableData *responseData;
    NSMutableArray *blogEntries;
    MBProgressHUD *HUD;
}

@property (nonatomic, retain) IBOutlet UIWindow *window;
@property (nonatomic, retain) IBOutlet UITabBarController *rootController;
@property (nonatomic, retain) IBOutlet FirstNavViewController *viewController;
@property (nonatomic, retain) IBOutlet SecondTableViewController *viewController1;
@property (nonatomic, retain) NSMutableArray *blogEntries;
@end

（AppDelegate.m）：

#import "AppDelegate.h"
#import "FirstNavViewController.h"
#import "SecondTableViewController.h"
#import "SBJson.h"
#define TMP NSTemporaryDirectory()

@implementation AppDelegate

@synthesize window = _window;
@synthesize rootController;
@synthesize viewController;
@synthesize viewController1;
@synthesize blogEntries;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.
    CGFloat width = self.rootController.view.bounds.size.width;
    CGFloat height = self.rootController.view.bounds.size.height;
    UIView *v = [[UIView alloc] initWithFrame:CGRectMake(0.0, 0.0, width, height)];
    UIImage *imageView = [UIImage imageNamed:@"theme_frame.png"];
    UIColor *kMainColor = [[UIColor alloc] initWithPatternImage:imageView];

    [v setBackgroundColor:kMainColor];
    [kMainColor release];
    [self.rootController.tabBar insertSubview:v atIndex:0];
    imageView = nil;
    [v release];

    responseData = [[NSMutableData data] retain];
    blogEntries = [NSMutableArray array];
    NSURLRequest *request = [NSURLRequest requestWithURL:
                             [NSURL URLWithString:@"ENTER_JSON_URL_HERE"]];
    [[NSURLConnection alloc] initWithRequest:request delegate:self];

    NSAssert(nil != self.rootController, @"tab bar controller not hooked up!");

    BOOL iPad = NO;
#ifdef UI_USER_INTERFACE_IDIOM
    iPad = (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad);
#endif

    if (iPad) {
        self.viewController = [[[FirstNavViewController alloc] initWithNibName:@"FirstNavViewController_iPad" bundle:nil] autorelease];
        self.viewController1 = [[[SecondTableViewController alloc] initWithNibName:@"SecondTableViewController_iPad" bundle:nil] autorelease];
    }
    else {
        self.viewController = [[[FirstNavViewController alloc] initWithNibName:@"FirstNavViewController_iPhone" bundle:nil] autorelease];
        self.viewController1 = [[[SecondTableViewController alloc] initWithNibName:@"SecondTableViewController_iPhone" bundle:nil] autorelease];
    }

    self.rootController.viewControllers = [NSArray arrayWithObject:self.viewController];

    self.rootController.selectedIndex = 0;

#if __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_4_0
    self.window.rootViewController = self.rootController;
#else
    [self.window addSubview:rootController.view];
#endif

    [self.window makeKeyAndVisible];

    HUD = [[MBProgressHUD alloc] initWithView:viewController.view];
    [viewController.view addSubview:HUD];
    [HUD show:NO];

    // Regisete for HUD callbacks so we can remove it from the window at the right time
    HUD.delegate = self;

    HUD.labelText = @"Loading";

    return YES;
}

#pragma mark NSURLConnection delegate methods
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
    [responseData setLength:0];
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
    [responseData appendData:data];
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
    [HUD hide:YES];
    [connection release];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    [connection release];
    NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
    [responseData release];

    NSMutableArray *allBlogEntries = [responseString JSONValue];
    [viewController1 setBlogEntries:allBlogEntries];
    [responseString release];
    [HUD hide:YES];

}

- (void)dealloc
{
    [_window release];
    [rootController release];
    [viewController release];
    [viewController1 release];
    [super dealloc];
}

@end

（FirstNavViewController.h）：

#import <UIKit/UIKit.h>

@interface FirstNavViewController : UIViewController {
    UINavigationController *navController;

}
@property (nonatomic, retain) UINavigationController *navController;
@end

（FirstNavViewController.m）：

#import "FirstNavViewController.h"
#import "SecondTableViewController.h"

@implementation FirstNavViewController

@synthesize navController;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
        UITabBarItem *tabBarItem = [self tabBarItem];
        UIImage *tabBarImage = [UIImage imageNamed:@"blog.png"];
        [tabBarItem setImage:tabBarImage];
        [tabBarItem setTitle:@"Blog"];
    }
    return self;
}

- (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.
}

#pragma mark - View lifecycle

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
    navController = [[UINavigationController alloc] initWithRootViewController:self];
    SecondTableViewController *secondViewController = [[SecondTableViewController alloc] initWithNibName:@"BlogOverviewViewController_iPhone" bundle:nil];
    [navController pushViewController:secondViewController animated:NO];
    [blogOverviewViewController release];
    [self.view addSubview:navController.view];
}

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

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

@end

（SecondTableViewController.h）：

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

@interface SecondTableViewController : UIViewController {
    NSMutableArray *blogEntries;
    IBOutlet UITableView *tView;
}
@property (nonatomic, retain) NSMutableArray *blogEntries;
@property (nonatomic, retain) NSArray *arryData;
@property (nonatomic, retain) IBOutlet UITableView *tView;
@end

（SecondTableViewController.m）：

#import "SecondTableViewController.h"
#import "ThirdDetailViewController.h"
#import "NSString+HTML.h"

NSString *convertedString;

@implementation SecondTableViewController

@synthesize arryData;
@synthesize tView;


-(NSMutableArray*)blogEntries {
    return [[blogEntries retain] autorelease];
}

-(void)setBlogEntries:(NSMutableArray*)newBlogEntries {
    if(newBlogEntries != blogEntries) {
        [newBlogEntries retain];

        [blogEntries release];
        blogEntries = newBlogEntries;

        [tView reloadData];
    }
}

#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 [blogEntries count];
}

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

    static NSString *CellIdentifier = @"Cell";

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

    // Set up the cell...
    NSDictionary *aBlogEntry = [blogEntries objectAtIndex:[indexPath row]];
    NSArray *bPosts = (NSArray *)[aBlogEntry objectForKey:@"posts"];

    NSString *stringToConvert = [bPosts valueForKey:@"title_plain"];
    NSString *convertedString = [stringToConvert stringByConvertingHTMLToPlainText];

    cell.textLabel.text = convertedString;
    cell.textLabel.adjustsFontSizeToFitWidth = YES;
    cell.textLabel.font = [UIFont systemFontOfSize:12];
    cell.textLabel.minimumFontSize = 10;
    cell.textLabel.numberOfLines = 4;
    cell.textLabel.lineBreakMode = UILineBreakModeWordWrap;

    NSString *stringToConvert1 = [bPosts valueForKey:@"excerpt"];
    NSString *convertedString1 = [stringToConvert1 stringByConvertingHTMLToPlainText];

    cell.detailTextLabel.text = convertedString1;

    return cell;
}


#pragma mark -
#pragma mark Table view delegate

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    ThirdDetailViewController *detailViewController = [[ThirdDetailViewController alloc] initWithNibName:@"BlogContentViewController_iPhone" bundle:nil];
    [self.navigationController pushViewController:detailViewController animated:YES];
    NSDictionary *aBlogEntry = [blogEntries objectAtIndex:[indexPath row]];
    NSArray *bPosts = (NSArray *)[aBlogEntry objectForKey:@"posts"];

    NSString *stringToConvert = [bPosts valueForKey:@"title"];
    NSString *convertedString = [stringToConvert stringByConvertingHTMLToPlainText];

    [contentViewController changeTitleTextLabel:convertedString];

    NSString *stringToConvert1 = [bPosts valueForKey:@"content"];
    NSString *convertedString1 = [stringToConvert1 stringByConvertingHTMLToPlainText];

    NSString *newConvertedString1 = [convertedString1 stringByReplacingOccurrencesOfString: @"\n" withString:@"\n\n"];

    [detailViewController changeContentTextLabel:newConvertedString1];

    [tableView deselectRowAtIndexPath: indexPath animated: YES];
}

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

- (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.
}

#pragma mark - View lifecycle

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
    blogEntries = [[NSMutableArray alloc]init];
    self.title = @"Blog";
    [self.navigationItem setHidesBackButton:YES animated:NO];
}

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

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

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

@end

有谁知道问题是什么？我坚持为什么UITableView不会重新加载数据。

编辑：小背景：我正在使用带有UIViewController的UITabBarController（AppDelegate），UINavigationController作为UIViewController（FirstNavViewController）的子视图。然后UINavigationController有一个子视图，其中包含另一个UIViewController。后者的UIViewController（SecondTableViewController）包含一个UITableView。

Answer 1

我刚刚遇到这个问题。原来对我来说是一个线程问题。对于那些在搜索后结束的人来说，这是我的快速修复：

[tView performSelectorOnMainThread:@selector(reloadData) 
                        withObject:nil
                     waitUntilDone:false];

似乎需要在主线程上调用reloadData。我希望这有帮助（^ _ ^）

Answer 2

在viewDidLoad方法中，添加：tView.delegate = self;

Answer 3

您的视图设置可能是您遇到问题的原因。

我真的不了解您的实现细节，但现在您将SecondTableViewController添加到选项卡栏控制器，然后添加到FistNavViewController viewDidLoad方法中的导航控制器堆栈。

使用FistNavViewController作为rootViewController创建导航控制器，然后将导航控制器作为第一个视图控制器添加到UITabBarViewController

（此处的代码是从内存中输入的，请原谅任何错别字）

FirstNavViewController *vc = [[FirstNavViewController alloc] initWithNibName:@"nibname" andBundleName:nil];
UINavigationController *nc = [[UINavigationController alloc] initWithRootViewController:vc];
UITabBarController *tbc = [UITabBarController setViewControllers:[NSArray arrayWithObjects:nc, otherVc1Example, otherVc2Example, nil] animated:NO];

在FirstNavViewController viewDidLoad方法中，您可以实例化SecondTableViewController并将其推入堆栈

[self.navigationController pushViewController:secondTableViewController animated:YES];

最后，在该nav控制器中，您需要确保在Interface Builder中（通过将数据源和委托出口连接到文件所有者）或在代码中通过手动将tableview委托和数据源设置为self来正确设置UITableView

如果您使用Interface Builder，那么您在上面尝试做的所有事情都会变得更容易，而且更不容易出错。在MainWindow.xib中，添加一个标签栏控制器，然后根据需要添加导航控制器和视图控制器。它应该“开箱即用”。

祝你好运。 ROG