iOS 文件下载

最新推荐文章于 2024-10-10 10:59:38 发布

原创最新推荐文章于 2024-10-10 10:59:38 发布 · 337 阅读

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本文介绍了一个iOS应用中实现文件下载任务的方法，包括创建下载路径、请求URL、接收响应及数据等关键步骤，并通过代理模式来处理下载过程中的各种事件。

-(void)downloadWithURL :(NSString *)url {
    
    //创建下载路径
   // NSURL *urlEncode = [NSURL URLWithString:[url stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
    NSURL *urlEncode = [NSURL URLWithString:url];
    //创建一个请求
    NSURLRequest *request=[NSURLRequest requestWithURL:urlEncode];
    
    //发送请求（使用代理的方式）
    NSURLConnection *connt=
    [NSURLConnection connectionWithRequest:request delegate:self];
    [connt start];
}
-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{
    
    NSString *caches=[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];

    NSString *createPath=[caches stringByAppendingPathComponent:@"MyMusicDownload"];

    
    //创建一个文件夹,到沙盒中
    NSFileManager *mgr=[NSFileManager defaultManager];
        // [mgr createFileAtPath:filePath contents:nil attributes:nil];
    
       if ([[NSFileManager defaultManager] fileExistsAtPath:createPath])//判断createPath路径文件夹是否已存在，此处createPath为需要新建的文件夹的绝对路径
        {
           
        }
        else
        {
    
           [[NSFileManager defaultManager] createDirectoryAtPath:createPath withIntermediateDirectories:YES attributes:nil error:nil];//创建文件夹
        }
    NSString *filePath=[createPath stringByAppendingPathComponent:response.suggestedFilename];
    
   // NSLog(@"%@",response.suggestedFilename);
    [mgr createFileAtPath:filePath contents:nil attributes:nil];
    //3.创建写数据的文件句柄
    self.writeHandle=[NSFileHandle fileHandleForWritingAtPath:filePath];
    
    //4.获取完整的文件的长度
    self.sumLength=response.expectedContentLength;
    
    if (self.delegate&&[self.delegate respondsToSelector:@selector(startDownload)]) {
        [self.delegate startDownload];
        
    }
    
}
-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
   
    //累加接收到的数据
    self.currentLength+=data.length;
    
    //计算当前进度(转换为double型的)
    double progress=(double)self.currentLength/self.sumLength;
    if (self.delegate&&[self.delegate respondsToSelector:@selector(setProgressView:)]) {
    
        [self.delegate setProgressView:progress];
    }
    //  self.progress.progress=progress;
    
    //一点一点接收数据。
    NSLog(@"接收到服务器的数据！---%lu",(unsigned long)data.length);
    
    //把data写入到创建的空文件中，但是不能使用writeTofile(会覆盖)
    //移动到文件的尾部
    [self.writeHandle seekToEndOfFile];
    //从当前移动的位置，写入数据
    [self.writeHandle writeData:data];
    
    
}
-(void) connectionDidFinishLoading:(NSURLConnection *)connection{
    NSLog(@"下载完毕");
    
    //关闭连接，不再输入数据在文件中
    [self.writeHandle closeFile];
    //销毁
    self.writeHandle=nil;
    
    //在下载完毕后，对进度进行清空
    self.currentLength=0;
    self.sumLength=0;
    
    globalVariable = [GlobalVariable sharedManager];
    [globalVariable setArrDoneDownloadList:[_arrWillDownload objectAtIndex:0]];
    [[NSNotificationCenter defaultCenter]postNotificationName:@"arrMutDoneDownloadChange" object:nil];
    
    if(_arrWillDownload.count != 0){
    [_arrWillDownload removeObjectAtIndex:0];
    }
    if (self.delegate&&[self.delegate respondsToSelector:@selector(finishDownload)]) {
        [self.delegate finishDownload];
    }
    
    if(_arrWillDownload.count != 0){
       
        [self startDownload];
    }
}