小编Jon*_*nes的帖子

我正在加载一个JSON,但我想检查"URL": "",json中是否为空,有时ID是空的,我该怎么检查？

if(URL == HOW TO CHECK IF EMPTY?)
{

}
else
{

}

错误:

*** Terminating app due to uncaught exception 'NSRangeException', reason: '*** -[__NSArrayI objectAtIndex:]: index 0 beyond bounds for empty array'
*** First throw call stack:

我正在尝试更新我的UITableview,但是当我调用[tableView reloadData];表时不会更新,在我更改后滚动tableview上面的单元格名称.但它并没有添加新的行或类似的东西.

-(void)update {
        [tableView reloadData];

    NSLog(@" %i", [tableData count]);
}

当我添加一行它返回2但是表没有更新时,nslog正在退回1.

- (void) refresh:(id)sender {  


    NSString *jsonString = [NSString 
                            stringWithContentsOfURL:[NSURL URLWithString:xmlDataUrl] 
                            encoding:NSUTF8StringEncoding
                            error:nil];


    SBJSON *parser = [[SBJSON alloc] init];
    NSDictionary *results = [parser objectWithString:jsonString error:nil];

    parser = nil;

    [self setTableData:[results objectForKey:@"items"]];
        [self performSelector:@selector(update) withObject:nil afterDelay:.2];


}

.

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{

    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        // Change UITableViewCellStyle
        cell = [[UITableViewCell alloc] 
                initWithStyle:UITableViewCellStyleSubtitle …

我已经以UITabBar编程方式定义了一个但是如何UITabBar在项目处于活动状态时设置自定义图标？

这是我用于声明UITabBar按钮的代码,但是如何在活动时设置自定义图像？

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];

    if (self) {
        self.title = NSLocalizedString(@"Free", @"Free");
        self.tabBarItem.image = [UIImage imageNamed:@"Free.png"];
    }

    return self;
}

通常我正在解析像(例子)的JSON提要;

{
    "AppStore": [
        {
            "Application": "Game",
            "KeyID": "zero"
        }
    ]
}

在我的JSON中,我正在做

NSArray* Parse = [json objectForKey:@"AppStore"]; 

但我现在想解析它有另一个结构的AppStore的JSON

http://itunes.apple.com/lookup?id=387633954

{
    "resultCount": 1,
    "results": [
        {
            "kind": "software",
            "features": [
                "gameCenter",
                "iosUniversal"
            ],
            "supportedDevices": [
                "all"
            ],
            "isGameCenterEnabled": true,
            "artistViewUrl": "http://itunes.apple.com/us/artist/mcsebi/id387633957?uo=4",
            "artworkUrl60": "http://a5.mzstatic.com/us/r1000/072/Purple/v4/98/a6/56/98a656e8-666a-89ab-c8f0-878b61b9f8f2/Icon.png",
            "screenshotUrls": [
                "http://a3.mzstatic.com/us/r1000/076/Purple/v4/fe/36/80/fe3680ae-5439-a2f1-6675-d3246b64f333/mza_11015238406403423.png",
                "http://a4.mzstatic.com/us/r1000/099/Purple/v4/73/98/1c/73981cbf-fb79-dc38-9dac-61ab46c2ac60/mzl.gzibbhfx.png",
                "http://a3.mzstatic.com/us/r1000/103/Purple/v4/72/b6/87/72b68713-7e5a-f675-83c3-85c2f0e96df1/mzl.gykakuht.png",
                "http://a1.mzstatic.com/us/r1000/113/Purple/v4/fa/d6/c4/fad6c453-9da5-2506-2b06-42ed5ff6bd63/mzl.hqbrlhog.png",
                "http://a2.mzstatic.com/us/r1000/120/Purple/v4/9e/7a/13/9e7a1388-5089-11e7-0c03-3d1868abbb82/mzl.jogfcyqv.png"
            ],
            "ipadScreenshotUrls": [
                "http://a1.mzstatic.com/us/r1000/096/Purple/v4/1f/5a/92/1f5a9249-03b8-90dc-8226-18b1785d5f7d/mzl.ilqgfose.1024x1024-65.jpg",
                "http://a5.mzstatic.com/us/r1000/070/Purple/v4/79/74/6b/79746ba8-7ea0-6e81-93d0-9e2493412e21/mzl.saleskru.1024x1024-65.jpg",
                "http://a1.mzstatic.com/us/r1000/068/Purple/v4/12/38/91/1238914f-7387-9c9e-06e4-11a55871b04a/mzl.qmiockwv.1024x1024-65.jpg",
                "http://a4.mzstatic.com/us/r1000/091/Purple/v4/3b/cf/62/3bcf62e6-4d84-4fc0-e721-c328361f5c95/mzl.somobtxy.1024x1024-65.jpg",
                "http://a1.mzstatic.com/us/r1000/074/Purple/v4/e9/d3/e7/e9d3e7b7-b52c-e204-e4b6-1ab5de79e85a/mzl.nedztyfk.1024x1024-65.jpg"
            ],
            "artworkUrl512": "http://a3.mzstatic.com/us/r1000/115/Purple/v4/0d/9c/ec/0d9cec04-91b3-5fe2-fa40-100660250f4a/mzl.kavmnegm.png",
            "artistId": 387633957,
            "artistName": "McSebi",
            "price": 0.99,
            "version": "1.2",
            "description": "Connect M is a simple, but very addictive puzzle game. …

我正在从Apple JSON(应用程序的评级)解析一些东西,我尝试了类似的东西:

 if ([StoreParse objectForKey:@"averageUserRating"] == @"4.5") {
        NSLog(@"xx");
    } else {
        NSLog(@"xxx");
    }

该应用程序的评级为4.5,如果我这样做

NSlog (@"%@", [StoreParse objectForKey:@"averageUserRating"]);

输出为:4.5

但是当我运行脚本时,第一个代码输出中的NSlog是"xxx",有人可以帮助我吗？