如何停止运行while - 循环并重新启动objective-c中的循环？

Question

我想通过点击段按钮停止运行while循环的过程但是我无法停止或中断循环，并且通过单击下一个按钮我想在循环时重新启动。

-(IBAction)SegmentClick:(id)sender
{
    if (segmentcntrl.selectedSegment == 0)
    {
        min=100.0;
        max=500.0;
    }
    else if (segmentcntrl.selectedSegment ==  1)
    {
        min=500.0;
        max=1024.0;

    here i want to restart while-loop  <-------

    }
    else if (segmentcntrl.selectedSegment == 2)
    {
        min=1024.0;
        max=5120.0;

       here i want to restart while-loop  <------- 

    }
    else if (segmentcntrl.selectedSegment == 3)
    {
        min=5120.0;
        max=100000.0;

       here i want to restart while-loop  <------- 

    }
    else if (segmentcntrl.selectedSegment == 4)
    {
        min=100.0;
        max=100000.0;

       here i want to restart while-loop  <-------

    }
    [self calculateLargerfiles];
    NSLog(@"called");
}

******这是我的循环******

    while (file = [de nextObject])
    {

    //NSLog(@"file %@",file);

    strPath = [NSString stringWithFormat:@"/Users/%@/",NSUserName()];

    strPath = [strPath stringByAppendingString:file];
    NSLog(@"path %@",strPath);

    //[test addObject:file.lastPathComponent];

    NSError *attributesError = nil;

    NSDictionary *fileAttributes = [[NSFileManager defaultManager] attributesOfItemAtPath:strPath error:&attributesError];

    NSNumber *fileSizeNumber = [fileAttributes objectForKey:NSFileSize];
    long long fileSize = [fileSizeNumber longLongValue];
    //NSLog(@"%lld",fileSize);

    //float sizeKB = ((float)fileSize / 1000);
    //NSLog(@"%f",sizeKB);

    float sizeMB = ((float)fileSize / 1000000);
    NSLog(@"%f",sizeMB);

    if(sizeMB >=min && sizeMB<=max)
    {
        [arrPathList addObject:strPath];
        [arrFiles addObject:file.lastPathComponent];

        if (sizeMB >=1000.0)
        {
            float sizeGB = ((float)fileSize / 1000000000);
            //NSLog(@"%f",sizeGB);

            NSString *strSize = [NSString stringWithFormat:@"%.1f GB",sizeGB];
            [arrSizes addObject:strSize];
        }
        else
        {
            NSString *strSize = [NSString stringWithFormat:@"%.1f MB",sizeMB];
            [arrSizes addObject:strSize];
        }

        NSLog(@"%@",arrPathList);
        NSLog(@"%@",arrFiles);
        NSLog(@"%@",arrSizes);

        dispatch_async(dispatch_get_main_queue(),^{

        [tblLargefiles reloadData];
        });
        //[tblLargefiles reloadData];


    }
    }

    NSLog(@"Path list  %@",arrPathList);
    NSLog(@"Files list %@",arrFiles);
    NSLog(@"Sizes list %@",arrSizes);

    //[tblLargefiles reloadData];
    [progressBar setHidden:YES];


}

我可以停止循环吗？