杂七杂八

NS_REQUIRES_NIL_TERMINATION

titles:(NSString *)firstTitle, ... NS_REQUIRES_NIL_TERMINATION

列表foot和header不滑动

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    CGFloat sectionHeaderHeight = 40;
    if (scrollView.contentOffset.y<=sectionHeaderHeight&&scrollView.contentOffset.y>=0) {
        scrollView.contentInset = UIEdgeInsetsMake(-scrollView.contentOffset.y, 0, 0, 0);
    }else if (scrollView.contentOffset.y>=sectionHeaderHeight) {
        scrollView.contentInset = UIEdgeInsetsMake(-sectionHeaderHeight, 0, 0, 0);
    }
}

剪裁图片尺寸

- (UIImage *)scaleFromImage:(UIImage *)image toSize:(CGSize)size
{
    UIGraphicsBeginImageContext(size);
    [image drawInRect:CGRectMake(0, 0, size.width, size.height)];
    UIImage * newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
    
}

时间戳

//时间戳 转成 时间
- (NSString *)dateTo:(NSString *)str
{
    NSTimeInterval time=[str integerValue];
    
    NSDate *detaildate=[NSDate dateWithTimeIntervalSince1970:time];
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    
    //设定时间格式,这里可以设置成自己需要的格式
    
    [dateFormatter setDateFormat:@"yyyy-MM-dd"];
    
    NSString *currentDateStr = [dateFormatter stringFromDate: detaildate];
    return currentDateStr;
}

//时间 转成 时间戳
- (NSString *)dateFromString:(NSString *)dateString{
    
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    
    [dateFormatter setDateFormat: @"yyyy-MM-dd"];
    
    
    
    
    NSDate *destDate= [dateFormatter dateFromString:dateString];
    NSString * timeSp = [NSString stringWithFormat:@"%ld",(long)[destDate timeIntervalSince1970]];
    return timeSp;
    
}

获取视频封面图片

- (UIImage *)thumbnailImageForVideo:(NSURL *)videoURL atTime:(NSTimeInterval)time{
    AVURLAsset * asset = [[AVURLAsset alloc] initWithURL:videoURL options:nil];
    NSParameterAssert(asset);
    AVAssetImageGenerator * assetImageGenerator = [[AVAssetImageGenerator alloc] initWithAsset:asset];
    
    assetImageGenerator.appliesPreferredTrackTransform = YES;
    assetImageGenerator.apertureMode =AVAssetImageGeneratorApertureModeEncodedPixels;
    
    CGImageRef thumnailImageRef = NULL;
    CFTimeInterval thumnailImageTime = time;
    NSError * thumnailImageGenerationError = nil;
    thumnailImageRef = [assetImageGenerator copyCGImageAtTime:CMTimeMake(thumnailImageTime, 60) actualTime:NULL error:&thumnailImageGenerationError];
    if (!thumnailImageRef) {
        NSLog(@"%@",thumnailImageGenerationError);
    }
    UIImage * thumbnailImage = thumnailImageRef?[[UIImage alloc] initWithCGImage:thumnailImageRef]:nil;
    return thumbnailImage;
}

书名

    NSString *dbPath = [NSHomeDirectory() stringByAppendingString:@"/Documents"];
    NSDirectoryEnumerator *enumerator = [[NSFileManager defaultManager]enumeratorAtPath:dbPath];
    for (NSString *fileName in enumerator)
    {
        NSLog(@"书名:   %@",fileName);
    }