NSMutableData保存到文件

Question

我使用下面显示的代码下载文件.然后我试图将NSMutableData变量保存到文件,但是,不创建该文件.我究竟做错了什么？我需要将NSMutableData转换为NSString吗？

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)_response {
    response = [_response retain];
    if([response expectedContentLength] < 1) {
        data = [[NSMutableData alloc] init];
    }
    else {
        data = [[NSMutableData dataWithCapacity:[response expectedContentLength]] retain];
    }
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)_data {
    [data appendData:_data];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    NSString *filePath = [[NSBundle mainBundle] pathForResource:@"file" ofType:@"txt"];

    NSLog(@"saved: %@", filePath);
    [data writeToFile:filePath atomically:YES];
    NSLog(@"downloaded file: %@", data); //all i see in log is some encoded data here
}

Answer 1

你不能在你的应用程序包中写.您需要将其保存在其他位置,例如您的应用程序的Documents目录:

NSString *documentsPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];
NSString *filePath = [documentsPath stringByAppendingPathComponent:@"file.txt"];
[data writeToFile:filePath atomically:YES];