Objective-C 将变量设置为方法返回的值

Question

我有这个代码：

-(NSURL *)urlOfCurrentlyPlayingInPlayer:(AVPlayer *)player{
// get current asset
AVAsset *currentPlayerAsset = player.currentItem.asset;

// make sure the current asset is an AVURLAsset
if (![currentPlayerAsset isKindOfClass:AVURLAsset.class]) return nil;

// return the NSURL
return [(AVURLAsset *)currentPlayerAsset URL];

}

为什么我不能这样做？

NSURL *currentSong=[urlOfCurrentlyPlayingInPlayer:_audioPlayer1];

错误消息是 "Expected expression" NSURL 的 N 带有红色下划线

抱歉这个菜鸟问题

Answer 1

假设在同一个 class 中声明了 urlOfCurrentlyPlayingInPlayer:

NSURL *currentSong = [self urlOfCurrentlyPlayingInPlayer:_audioPlayer1];

如果它是其他一些 class 的实例方法，它将是

NSURL *currentSong = [myInstanceOfSomeOtherClass urlOfCurrentlyPlayingInPlayer:_audioPlayer1];

Objective-C 将变量设置为方法返回的值

Objective-C set variable to what is returned from method

objective-c

avplayer

nsurl