观察currentPlaybackTime并以一定间隔显示叠加 [英] Observing currentPlaybackTime and showing an overlay at intervals

问题描述

我正在制作一个视频，在视频的特定间隔内显示叠加层。我设法让视频播放。现在我的目标是观看/观察currentPlaybackTime值，并在它达到2秒时暂停视频。

一些研究发现currentPlaybackTime不支持KOV。因此，我需要实施此解决方案，但我不知道在哪里放代码 - 我对Objective C非常新。我不断尝试把它放在ViewController（我唯一的视图），但它的书面提示的方式放置在其他地方...

我应该为它创建一个新的控制器吗？

$ b

这是我的代码：

  #import< UIKit / UIKit.h> 
 #import< MediaPlayer / MediaPlayer.h> 
 
 @interface ViewController：UIViewController 
 
 @property（强，非原子）MPMoviePlayerController * movieController; 
 
 @property（nonatomic）NSTimeInterval currentPlaybackTime; 
 
 @end 
 
 
 
 #importViewController.h
 
 @interface ViewController（）
 
 @end 
 
 @implementation ViewController 
 
  - （void）viewDidLoad 
 {
 [super viewDidLoad]; 
 //在加载视图之后执行任何其他设置，通常来自nib。 
} 
 
  - （void）didReceiveMemoryWarning 
 {
 [super didReceiveMemoryWarning]; 
 //处理可以重新创建的任何资源。 
} 
 
 
  - （void）viewDidAppear：（BOOL）animated {
 
 self.movi​​eController = [[MPMoviePlayerController alloc] init]; 
 
 
 NSString * moviePath = [[NSBundle mainBundle] pathForResource：@MovieofType：@m4v]; 
 NSURL * movieURL = [NSURL fileURLWithPath：moviePath]; 
 self.movi​​eController = [[MPMoviePlayerController alloc] initWithContentURL：movieURL]; 
 
 [self.movi​​eController.view setFrame：CGRectMake（0，0，480，326）]; 
 [self.view addSubview：self.movi​​eController.view]; 
 
 
 [self.movi​​eController play]; 
 [self.movi​​eController currentPlaybackTime]; 
 
 
 
 
} 
 
 
 
 @end 
  
解决方案
您可以在同一个视图控制器中找到的解决方案中实现以下方法。
 
 
 
之后
  [self.movi​​eController play]; 
  
调用以下方法
  [self BeginPlayerPolling]; 
 
在你的viewDidAppear中注册这个类作为观察者，你初始化你的movieController 
  [[NSNotificationCenter defaultCenter] addObserver：self 
 selector：@selector（movieFinishedCallback :) 
 name：MPMoviePlayerPlaybackDidFinishNotification 
 ：self.movi​​eController]; 
 self.movi​​eController = [[MPMoviePlayerController alloc] init]; 
  
并实现此通知的观察者方法
   - （void）movieFinishedCallback：（NSNotification *）aNotification 
 {
 //从播放完成通知观察者中删除电影播放器​​视图控制器
 [[NSNotificationCenter defaultCenter] removeObserver：self 
 name：MPMoviePlayerPlaybackDidFinishNotification 
 object：self.movi​​eController]; 
 [self EndPlayerPolling]; 
} 
  
 
I’m making a video that shows overlays at certain intervals of a video. I’ve managed to get the video to play. Now my objective is to watch/observe the currentPlaybackTime value and pause the video when it hits 2 seconds. 


After some research found that currentPlaybackTime does not support KOV. So I need to implement this solution but I have no idea where to put the code - I’m very new to Objective C. I keep trying to put it in the ViewController (My only view) but the way its written hints to it being placed somewhere else… 

Should I create a new controller for it? Or do I override methods from the MediaPlayer framework?

Here's my code:
#import <UIKit/UIKit.h>
#import <MediaPlayer/MediaPlayer.h>

@interface ViewController : UIViewController

@property (strong, nonatomic) MPMoviePlayerController *movieController;

@property(nonatomic) NSTimeInterval currentPlaybackTime;

@end



#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


- (void)viewDidAppear:(BOOL)animated {

    self.movieController = [[MPMoviePlayerController alloc] init];


    NSString *moviePath = [[NSBundle mainBundle] pathForResource:@"Movie" ofType:@"m4v"];
    NSURL *movieURL = [NSURL fileURLWithPath:moviePath];
    self.movieController = [[MPMoviePlayerController alloc] initWithContentURL:movieURL];

    [self.movieController.view setFrame:CGRectMake (0, 0, 480, 326)];
    [self.view addSubview:self.movieController.view];


    [self.movieController play];
    [self.movieController currentPlaybackTime];




}



@end

解决方案
You can implement following method in your found solution in this same view controller.

Right after
[self.movieController play];
call following method
[self BeginPlayerPolling];
Register this class as an observer before in your viewDidAppear where you initialised your movieController
[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(movieFinishedCallback:)
                                             name:MPMoviePlayerPlaybackDidFinishNotification
                                           object: self.movieController];
self.movieController = [[MPMoviePlayerController alloc] init];
and implement this notification observer's method
- (void)movieFinishedCallback:(NSNotification*)aNotification
{
    // Remove the movie player view controller from the "playback did finish" notification observers
    [[NSNotificationCenter defaultCenter] removeObserver: self
                                                name:MPMoviePlayerPlaybackDidFinishNotification
                                              object: self.movieController];
    [self EndPlayerPolling];
}


                        
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