ios - NSURLConnection如何获取剩余时间信息

Question

我在女巫中有一个表格单元格，我必须获得有关我正在下载的文件的更多信息，我设法获得了我需要的所有信息，但还有时间

这是我想做的一个例子，除了时间计算我都做了

获取文件大小:

fileSize = [NSNumber numberWithLongLong:[response expectedContentLength]]/(1024*1024);

已下载:

[_responseData length]/(1024*1024)

速度:

 double speed = [_responseData length] / ([NSDate timeIntervalSinceReferenceDate] - start);

其中 start 也是一个 [NSDate timeIntervalSinceReferenceDate] 设置在

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response 

剩余时间:???

问题:如何计算剩余时间？？

Answer 1

我想您需要做的是处理 connection:didReceiveData: 委托(delegate)方法。

@property (atomic, strong) NSDate *lastCheckDate;
@property (atomic, strong) NSDate *startDate;
@property (atomic, strong) NSNumber *fileSize;
@property (atomic, strong) NSNumber *sizeLeft;

- (void) connection:(NSURLConnection *) connection didReceiveData:(NSData *) data
{
    NSDate *now = [NSDate date];
    double dt = [now timeIntervalSinceDate:_lastCheckDate]; // time since last check
    self.lastCheckDate = now;
    double db = [data length]; // bytes received
    double speed = db / dt;
    self.sizeLeft = self.sizeLeft - [NSNumber numberWithDouble:db];
    double averageSpeed = [(_fileSize - _sizeLeft) doubleValue] / [now timeIntervalSinceDate:_startDate];
    // time left, based on current speed
    double timeLeftCurrent = [sizeLeft doubleValue] / speed;
    // time left, based on average speed
    double timeLeftAverage = [sizeLeft doubleValue] / averageSpeed;
}