我有一个应用程序,它遍历URL数组并下载该数组中的所有文件(10个小txt文件和1个大图像文件)。我以前让应用程序可以正常下载文件,但是由于图像过大而导致问题,我不得不将NSURLConnection子类化,并且由于没有文件正在下载,我认为我做得还不够。

对于数组getFiles的每个项目,都会传递一个URL并运行:

-(void)getFile:(NSString*)url tag:(NSString*)tag {
    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:url]];
    FileURLConnection *connection = [[FileURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES tag:tag];
    if (connection) {
        [receivedData setObject:[NSMutableData data] forKey:connection.tag];
    }
}

这是NSURLConnection委托:
-(NSMutableData*)dataForConnection:(FileURLConnection*)connection {
    NSMutableData *data = [receivedData objectForKey:connection.tag];
    return data;
}
- (void)connection:(FileURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
    NSUserDomainMask, YES) objectAtIndex:0]stringByAppendingPathComponent:fileName];
    NSMutableData *dataForConnection = [self dataForConnection:(FileURLConnection*)connection];
    [dataForConnection setLength:0];
}
- (void)connection:(FileURLConnection *)connection didReceiveData:(NSData *)data {
    NSMutableData *dataForConnection = [self dataForConnection:(FileURLConnection*)connection];
    [dataForConnection appendData:data];
}
- (NSCachedURLResponse *)connection:(FileURLConnection *)connection
              willCacheResponse:(NSCachedURLResponse*)cachedResponse {
    return nil;
}
- (void)connectionDidFinishLoading:(FileURLConnection *)connection {
    NSLog(@"connectionDidFinishLoading run");
    NSMutableData *dataForConnection = [self dataForConnection:(FileURLConnection *)connection];
    NSString *fileName = connection.tag;
    NSString *filePath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]stringByAppendingPathComponent:fileName];
    [[NSFileManager defaultManager] createFileAtPath:filePath contents:nil attributes:nil];
    file = [NSFileHandle fileHandleForUpdatingAtPath:filePath];
    [file seekToEndOfFile];
    [file writeData:dataForConnection];
    [file closeFile];
}

编辑:如果我在getFile中NSLogLog ReceivedData(NSDictionary),它会更新'tag'对象,但没有数据:
"accomodation.txt" = <>;
"future-congress-dates.txt" = <>;
"general-file.txt" = <>;
...

我还尝试过为每个委托NSLog dataForConnection(NSMutableData),但是什么也没打印出来:
NSLog(@"dataForConnection %@", dataForConnection);

最佳答案

好吧,我投降了。
有完整的代码:

FileURLConnection:

@interface FileURLConnection: NSURLConnection

@property (nonatomic, strong) NSFileHandle *file;

@end

getFile函数:
-(void)getFile {
    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:fullURL]];
    FileURLConnection *conn = [[FileURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES];
}
- (void)connection:(FileURLConnection*)connection didReceiveResponse:(NSURLResponse *)response {
    NSString *fileName = [[response URL] lastPathComponent];
    NSString *filePath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]stringByAppendingPathComponent:fileName];
    [[NSFileManager defaultManager] createFileAtPath:filePath contents:nil attributes:nil];
    connection.file = [NSFileHandle fileHandleForUpdatingAtPath:filePath];
}
- (void)connection:(FileURLConnection *)connection didReceiveData:(NSData *)data {
    [connection.file writeData:data];
}
- (NSCachedURLResponse *)connection:(FileURLConnection *)connection
              willCacheResponse:(NSCachedURLResponse*)cachedResponse {
    return nil;
}
- (void)connectionDidFinishLoading:(FileURLConnection *)connection {
    NSLog(@"Connection is %@", connection);
    [connection.file closeFile];
}
- (void)connection:(FileURLConnection *)connection didFailWithError:(NSError *)error {
    NSLog(@"error - %@", error);
}

原始问题:App crashing when downloading a large file - NSFileHandle seekToEndOfFile

10-07 19:51
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