iOS小知识点

获取图片缓存

1.导入  

#import "SDImageCache.h"

//把B单位转换为M

[NSString stringWithFormat:@"%.2fM",(double)[[SDImageCache sharedImageCache] getSize]/1000/1000];

清除图片缓存

[[SDImageCache sharedImageCache] clearDisk];

获取某文件夹中所有文件缓存

//文件夹枚举器，可以枚举这个文件夹内以及这个文件夹的子文件夹中的所有文件

            NSDirectoryEnumerator *enumerator = [[NSFileManager defaultManager] enumeratorAtPath:<[CommonTool fileDownloadPath]>>>需要遍历的文件夹路经];

unsigned long long totalSize = 0;

  while ([enumerator nextObject]) 

{

  totalSize+=[[enumerator fileAttributes] fileSize];

}

 [NSString stringWithFormat:@"%.2fM",(double)totalSize/1000/1000];

清理文件缓存

[[NSFileManager defaultManager] removeItemAtPath:<[CommonTool fileDownloadPath]>>>需要删除的文件夹路经 error:nil];

//push时自动隐藏tabBar

vc.hidesBottomBarWhenPushed = YES;

自适应高度

CGRect rect = [_news.intr-需要获取的字符串- boundingRectWithSize:CGSizeMake(SCREEN_WIDTH-30>-需要多宽折行, 0) options:NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesFontLeading attributes:@{NSFontAttributeName:[UIFont boldSystemFontOfSize:14]} context:nil];

return rect.size.height+30;

获取键盘的高度输入框自适应

 _inputView 是自定义的一个 View 加上 textField 的输入框 

[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(keyboardWillChangeFrame:) name:UIKeyboardWillChangeFrameNotification object:nil];

- (void)keyboardWillChangeFrame:(NSNotification *)noti{

   // NSLog(@"%@",noti.userInfo);

    CGRect rect = [[noti.userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];

    [UIView animateWithDuration:[[noti.userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] floatValue] animations:^{

        _inputView.frame = CGRectMake(0, rect.origin.y-40, SCREEN_WIDTH, 40);

        _tableView.frame = CGRectMake(0, 0, SCREEN_WIDTH, _inputView.frame.origin.y);

    }];

}

 ---用滑动方式让键盘下去

-(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{

     [self.view endEditing:YES];

}

气泡聊天 专用 从某个像素点拉申

self.bubbleImageView.image = [[UIImage imageNamed:@"bubbleSelf.png"] stretchableImageWithLeftCapWidth:25 topCapHeight:20];

//设置照片为圆形 常用语头像

self.headerImageView.layer.cornerRadius = 30—照片大小的半径;

    self.headerImageView.layer.masksToBounds = YES;

设置应用图标的角标

[[UIApplication sharedApplication] setApplicationIconBadgeNumber:number—需要获取的数];