-( float )readCacheSize
{
  NSString *cachePath = [NSSearchPathForDirectoriesInDomains (NSCachesDirectory , NSUserDomainMask , YES) firstObject];
  return [ self folderSizeAtPath :cachePath];
}

 

由于緩存文件存在沙箱中，我們可以通過NSFileManager API來實(shí)現(xiàn)對緩存文件大小的計算。
// 遍歷文件夾獲得文件夾大小，返回多少 M
- ( float ) folderSizeAtPath:( NSString *) folderPath{
  
  NSFileManager * manager = [NSFileManager defaultManager];
  if (![manager fileExistsAtPath :folderPath]) return 0 ;
  NSEnumerator *childFilesEnumerator = [[manager subpathsAtPath :folderPath] objectEnumerator];
  NSString * fileName;
  long long folderSize = 0 ;
  while ((fileName = [childFilesEnumerator nextObject]) != nil ){
    //獲取文件全路徑
    NSString * fileAbsolutePath = [folderPath stringByAppendingPathComponent :fileName];
    folderSize += [ self fileSizeAtPath :fileAbsolutePath];
  }

  return folderSize/( 1024.0 * 1024.0);
  
}

 

// 計算 單個文件的大小
- ( long long ) fileSizeAtPath:( NSString *) filePath{
  NSFileManager * manager = [NSFileManager defaultManager];
  if ([manager fileExistsAtPath :filePath]){
    return [[manager attributesOfItemAtPath :filePath error : nil] fileSize];
  }
  return 0;
}

 

- (void)clearFile
{
  NSString * cachePath = [NSSearchPathForDirectoriesInDomains (NSCachesDirectory , NSUserDomainMask , YES ) firstObject];
  NSArray * files = [[NSFileManager defaultManager ] subpathsAtPath :cachePath];
  //NSLog ( @"cachpath = %@" , cachePath);
  for ( NSString * p in files) {
    
    NSError * error = nil ;
    //獲取文件全路徑
    NSString * fileAbsolutePath = [cachePath stringByAppendingPathComponent :p];
    
    if ([[NSFileManager defaultManager ] fileExistsAtPath :fileAbsolutePath]) {
      [[NSFileManager defaultManager ] removeItemAtPath :fileAbsolutePath error :&error];
    }
  }
  
  //讀取緩存大小
  float cacheSize = [self readCacheSize] *1024;
  self.cacheSize.text = [NSString stringWithFormat:@"%.2fKB",cacheSize];

}