我有一个循环遍历一组 URL 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)的应用程序。我之前让应用程序下载文件没问题,但由于大图像的问题,我不得不将 NSURLConnection 子类化,我认为我没有完全正确,因为现在没有文件正在下载。
为数组 getFiles 中的每一项传递一个 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 代表:
-(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 中对 receivedData (NSDictionary) 进行 NSLog 更新,它会更新“标签”对象,但没有数据与之相关:
"accomodation.txt" = <>;
"future-congress-dates.txt" = <>;
"general-file.txt" = <>;
...
我也尝试过为每个代表记录 dataForConnection (NSMutableData),但没有打印任何内容:
NSLog(@"dataForConnection %@", dataForConnection);
最佳答案
好吧,我投降。 有完整代码:
文件网址连接:
@interface FileURLConnection: NSURLConnection
@property (nonatomic, strong) NSFileHandle *file;
@end
获取文件函数:
-(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
关于ios - 应用程序不使用 NSURLConnection 下载文件,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/22008702/