为什么 MPMovieLoadState 有状态 5？

Question

我找到MPMoviePlayerController.h，有

enum {
    MPMovieLoadStateUnknown        = 0,
    MPMovieLoadStatePlayable       = 1 << 0,
    MPMovieLoadStatePlaythroughOK  = 1 << 1, // Playback will be automatically started in this state when shouldAutoplay is YES
    MPMovieLoadStateStalled        = 1 << 2, // Playback will be automatically paused in this state, if started
};
typedef NSInteger MPMovieLoadState;

但是当我这样做时

NSLog(@"%d",player.loadState)

它打印出 5 或有时 3，它是如何发生的？我知道 loadstate 的值为 0、1、2、4，请参阅开发人员文档。 谢谢！

Answer 1

playState 是一个位掩码。可以设置任意位数，例如

MPMovieLoadStatePlaythroughOK | MPMovieLoadStatePlayable

检查这样的状态：

MPMovieLoadState state = [playerController loadState];
if( state & MPMovieLoadStatePlaythroughOK ) {
        NSLog(@"State is Playthrough OK");
}