笔记--9.10 (抓屏和文件路径初始化NSURL)

本文介绍如何在iOS应用中使用NSURL及MPMoviePlayerController播放指定路径的mp4视频，并实现异步截图功能。通过监听特定通知来触发截图完成后的处理流程。

1，使用文件路径初始化NSURL对象

NSString *path = [[NSBundle mainBundle] pathForResource:@"movie" ofType:@"mp4"];
NSURL *url = [NSURL fileURLWithPath:path];
moviePlay = [[MPMoviePlayerController alloc] initWithContentURL:url];

2，异步抓屏

a,首先添加观察者，并实现观察到后的处理方法。

[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(didReceived:) name:MPMoviePlayerThumbnailImageRequestDidFinishNotification object:nil];

b，调用异步抓屏方法，抓取完毕后，发送相应通知。

[movieViewCtrl.moviePlayer  requestThumbnailImagesAtTimes:array timeOption:MPMovieTimeOptionExact];
[[NSNotificationCenter  defaultCenter] postNotificationName:MPMoviePlayerThumbnailImageRequestDidFinishNotification object:nil];

c，处理方法的具体实现

- (void)didReceived:(NSNotification *)notif
{
    UIImage *catchPic = [notif.userInfo objectForKey:MPMoviePlayerThumbnailImageKey];
    //采用switch并不好，因为switch的参数只能是整数。
    if (catchPic) {
        switch ([[notif.userInfo objectForKey:MPMoviePlayerThumbnailTimeKey] intValue]) {
            case 2:
                self.catchImageView.image = catchPic;
                [self.view addSubview:_catchImageView];
                break;
            case 8:
                self.secondCatchImageView.image = catchPic;
                [self.view addSubview:_secondCatchImageView];
                break;
            default:
                break;
        }
    }
    
}