1.

UIImage imageWithContentsOfFile卡顿

[[UIImage alloc] initWithContentsOfFile 卡顿

2.uitableview scroll to top

NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0];

[_commentsTab scrollToRowAtIndexPath:indexPath atScrollPosition:UITableViewScrollPositionNone animated:NO];

修改为

[mainTableView setContentOffset:CGPointZero animated:YES];

http://*.com/questions/724892/uitableview-scroll-to-the-top

3.

Can't add self as subview

https://www.douban.com/note/536194761/

4.

self.player.movieSourceType = MPMovieSourceTypeStreaming;

http://www.jianshu.com/p/b7fc2516162b

5.

[AVCaptureMetadataOutput setMetadataObjectTypes:] Unsupported type found - use -availableMetadataObjectTypes

http://blog.csdn.net/jf200614379/article/details/50956910

6.

was mutated while being enumerated.

http://blog.it985.com/144.html

7.

list_for_each_safe

http://blog.csdn.net/kangear/article/details/43712085

nsmutablearray 删除

http://blog.csdn.net/mingerw/article/details/51207158

.将要删除的字符串所在的下表添加在一个NSMutableIndexSet 中，最后一起删除

    NSMutableArray *arr1 = [[NSMutableArrayalloc]initWithObjects:@"QQQ",@"ABC",@"DEF",@"ABC",@"ABC",@"QWE",@"TTT",nil];

    NSMutableIndexSet *set = [[NSMutableIndexSetalloc]init];

    for(int i = ; i < arr1.count ; i++)

    {

        NSString *str = arr1[i];

        if([str isEqualToString:@"ABC"])

        {

            [set addIndex:i];

        }

    }

    [arr1 removeObjectsAtIndexes:set];