Question

我使用以下代码尝试从iTunes API获取trackName。它应该来自这个链接，例如： https://itunes.apple.com/search?term=EMINEM&entity=song&limit=3 它一直没有返回（标签是空白的，不是因为标签太小）

- (void)pressSearchKey {
    NSInteger numberOfResults = 3;
    NSString *searchString = self.keyboard.textField.text;

    NSString *encodedSearchString = [searchString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    NSString *finalSearchString = [NSString stringWithFormat:@"https://itunes.apple.com/lookup?term=%@&entity=song&limit=%ld",searchString,numberOfResults];

    NSURL *searchURL = [NSURL URLWithString:finalSearchString];
    dispatch_queue_t iTunesQueryQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

    dispatch_async(iTunesQueryQueue, ^{
        NSError *error = nil;
        NSData *data = [[NSData alloc] initWithContentsOfURL:searchURL options:NSDataReadingUncached error:&error];

        if (data && !error) {
            NSDictionary *JSON = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:nil];

            NSArray *array = [JSON objectForKey:@"results"];
            NSArray *arrayTracks;
            for (NSDictionary *bpDictionary in array) {
                arrayTracks = [bpDictionary objectForKey:@"trackName"];
            }
            dispatch_async(dispatch_get_main_queue(), ^{
                self.keyboard.firstLabel.text = [arrayTracks objectAtIndex:1];
            });
        }
    });
}

Answer 1

你也遇到了一些问题。

在构建encodedSearchString

finalSearchString

您的示例网址会调用https://itunes.apple.com/ 搜索，而代码中的网址为https://itunes.apple.com/ 查找。将其更改为搜索会返回预期结果。

修正：

NSInteger numberOfResults = 3;
NSString *searchString = @"EMINEM";

NSString *encodedSearchString = [searchString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSString *finalSearchString = [NSString stringWithFormat:@"https://itunes.apple.com/search?term=%@&entity=song&limit=%ld",encodedSearchString,numberOfResults];

NSURL *searchURL = [NSURL URLWithString:finalSearchString];
dispatch_queue_t iTunesQueryQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

dispatch_async(iTunesQueryQueue, ^{
    NSError *error = nil;
    NSData *data = [[NSData alloc] initWithContentsOfURL:searchURL options:NSDataReadingUncached error:&error];

    if (data && !error) {
        NSDictionary *JSON = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:nil];

        NSArray *array = [JSON objectForKey:@"results"];
        NSArray *arrayTracks;
        for (NSDictionary *bpDictionary in array) {
            arrayTracks = [bpDictionary objectForKey:@"trackName"];
        }
        dispatch_async(dispatch_get_main_queue(), ^{
            NSLog(@"%@", [arrayTracks objectAtIndex:1]);
        });
    }
});

iOS json无法从iTunes API中检索数据

1 个答案: