在iOS中下载zip文件

Question

尝试从给定的URL下载一个zip文件,因为zip文件每天更新​​我在ApplicationDidFinishLunching方法中编写了代码,但它不起作用.我的代码有什么问题吗？

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.
    NSString *stringURL = @"http://webspace.apiit.edu.my/intake-timetable/download_timetable/timetableXML.zip";
    NSURL  *url = [NSURL URLWithString:stringURL];
    NSData *urlData = [NSData dataWithContentsOfURL:url];
    //Find a cache directory. You could consider using documenets dir instead (depends on the data you are fetching)
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
    NSString *path = [paths  objectAtIndex:0];

    //Save the data
    NSString *dataPath = [path stringByAppendingPathComponent:@"timetableXML.zip"];
    dataPath = [dataPath stringByStandardizingPath];
    [urlData writeToFile:dataPath atomically:YES];
    return YES;
}

Answer 1

试试这个,因为它将在后台下载zip文件.即使文件只有几kb,下载也需要一些时间,因为下载是在主线程上执行的,这将阻止应用程序启动!

dispatch_queue_t queue = dispatch_get_global_queue(0,0);
dispatch_async(queue, ^{

    NSLog(@"Beginning download");
    NSString *stringURL = @"http://webspace.apiit.edu.my/intake-timetable/download_timetable/timetableXML.zip";
    NSURL  *url = [NSURL URLWithString:stringURL];
    NSData *urlData = [NSData dataWithContentsOfURL:url];

    //Find a cache directory. You could consider using documenets dir instead (depends on the data you are fetching)
    NSLog(@"Got the data!");
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
    NSString *path = [paths  objectAtIndex:0];

    //Save the data
    NSLog(@"Saving");
    NSString *dataPath = [path stringByAppendingPathComponent:@"timetableXML.zip"];
    dataPath = [dataPath stringByStandardizingPath];
    [urlData writeToFile:dataPath atomically:YES];

});

您永远不应该在主线程上下载任何内容,因为它会"阻止"您的应用程序.但是应该注意,有更好的方法来下载数据.阅读例如这个.