检查Documents Directory Url是否为空

Question

在下面的代码中，我试图检查我的Documents Directory Url是否为空，因此，如果它为空，它将立即显示或继续执行我所需的一切。

这是我的代码：

- (IBAction)saveVideo:(id)sender {
    NSURL *vedioURL;
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSArray *filePathsArray = [[NSFileManager defaultManager] subpathsOfDirectoryAtPath:documentsDirectory  error:nil];
    NSLog(@"files array %@", filePathsArray);

    NSString *fullpath;
    for ( NSString *apath in filePathsArray )
    {
        fullpath = [documentsDirectory stringByAppendingPathComponent:apath];
        vedioURL =[NSURL fileURLWithPath:fullpath];
    }
    NSLog(@"vurl %@",vedioURL);
    NSURL *movieUrl = [NSURL fileURLWithPath:fullpath];
    NSString *moviePath = [movieUrl path];

    if (videoUrl.absoluteString.length == 0) {
        NSLog(@"No way");
    } else {
        self.imageViewPost.image = [self generateThumbImage:moviePath];
        AVPlayerItem * playeritem = [AVPlayerItem playerItemWithURL:vedioURL];
        [_player replaceCurrentItemWithPlayerItem:playeritem];
        [_player play];
        [self clearTmpDirectory];
    }
}

应用程序崩溃了，它向我的网址显示了Null值：

vurl (null)
2017-11-29 20:54:24.288473+0400 EasyVideo[43587:2429960] ***
Terminating app due to uncaught exception 'NSInvalidArgumentException',
 reason: '*** -[NSURL initFileURLWithPath:]: nil string parameter'

我希望解决这个问题。 谢谢

Answer 1

您可以先从URL获取数据，然后检查数据是否为空。

NSData *data = [NSData dataWithContentsOfURL:videoURL];

在这里，如果数据不为空，您将相应地执行任务：

 if (data == nil) 
  {
       //Do not perform the task.

  }
else 
  {
      //perform the task
  }