琐碎的知识，先放一起，以后整理

1.一个非常重要的网站，苹果的各种开发文档如果变更都会更新这个网站：

https://developer.apple.com/library/downloads/docset-index.dvtdownloadableindex。

2.//sdwebimage缓存图片大小

- (float)checkTmpSize

{

float totalSize = 0;

NSString *cachePath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];

cachePath = [cachePath stringByAppendingPathComponent:@"default"];

NSDirectoryEnumerator *fileEnumerator = [[NSFileManager defaultManager] enumeratorAtPath:cachePath];

for (NSString *fileName in fileEnumerator)

{

NSString *filePath = [cachePath stringByAppendingPathComponent:fileName];

NSDictionary *attrs = [[NSFileManager defaultManager] attributesOfItemAtPath:filePath error:nil];

unsigned long long length = [attrs fileSize];

totalSize += length / 1024.0 / 1024.0;

}

NSLog(@"tmp size is %.2f",totalSize);

return totalSize;

}

3.修改statusbar

- (UIStatusBarStyle)preferredStatusBarStyle{

return UIStatusBarStyleLightContent;

}

在某个控制器里写这

有导航控制器的 VC中使用 preferredStatusBarStyle方法 不被调用的解决办法

self.navigationController.navigationBar.barStyle = UIBarStyleBlack;