端午節前，把公司的專案忙完了，這幾天開始繼續DDPlayer的開發，熟悉程式碼之後，首先要解決的是：獲取並播放相簿裡面的視訊。
對於相簿中的視訊，我需要關注視訊的名稱、時常、格式、縮圖等資訊，因此，定義了表示視訊資訊的物件。

//AlbumVideoInfo.h
#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>

@interface AlbumVideoInfo : NSObject

@property(nonatomic, copy) NSString *name;
@property(nonatomic
 
, assign) long long size; //Bytes
@property(nonatomic, strong) NSNumber *duration;
@property(nonatomic, copy) NSString *format;
@property(nonatomic, strong) UIImage *thumbnail;
@property (nonatomic, strong) NSURL *videoURL;

@end

//AlbumVideoInfo.m
#import "AlbumVideoInfo.h"

@implementation AlbumVideoInfo
 


@end

然後，從相簿load視訊資訊，並儲存在陣列中，相關關鍵函式有：

//載入視訊
- (void)loadVideos{
    ALAssetsLibrary *library1 = [[ALAssetsLibrary alloc] init];
    [library1 enumerateGroupsWithTypes:ALAssetsGroupAll usingBlock:^(ALAssetsGroup *group, BOOL *stop) {
        if (group) {
            [group setAssetsFilter:[ALAssetsFilter allVideos]]
 
;
            [group enumerateAssetsUsingBlock:^(ALAsset *result, NSUInteger index, BOOL *stop) {

                if (result) {
                    AlbumVideoInfo *videoInfo = [[AlbumVideoInfo alloc] init];
                    videoInfo.thumbnail = [UIImage imageWithCGImage:result.thumbnail];
//                    videoInfo.videoURL = [result valueForProperty:ALAssetPropertyAssetURL];
                    videoInfo.videoURL = result.defaultRepresentation.url;
                    videoInfo.duration = [result valueForProperty:ALAssetPropertyDuration];
                    videoInfo.name = [self getFormatedDateStringOfDate:[result valueForProperty:ALAssetPropertyDate]];
                    videoInfo.size = result.defaultRepresentation.size; //Bytes
                    videoInfo.format = [result.defaultRepresentation.filename pathExtension];
                    [_albumVideoInfos addObject:videoInfo];
                }
            }];
        } else {
            //沒有更多的group時，即可認為已經載入完成。
             NSLog(@"after load, the total alumvideo count is %ld",_albumVideoInfos.count);
            dispatch_async(dispatch_get_main_queue(), ^{
                [self showAlbumVideos];
            });
        }

    } failureBlock:^(NSError *error) {
        NSLog(@"Failed.");
    }];
}

//將建立日期作為檔名
-(NSString*)getFormatedDateStringOfDate:(NSDate*)date{

    NSDateFormatter* dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setTimeZone:[NSTimeZone localTimeZone]];
    [dateFormatter setDateFormat:@"yyyyMMddHHmmss"]; //注意時間的格式：MM表示月份，mm表示分鐘，HH用24小時制，小hh是12小時制。
    NSString* dateString = [dateFormatter stringFromDate:date];
    return dateString;
}

最後，就是播放視訊，由於相簿視訊不能獲取到絕對地址，而KxMovieViewController初始化的引數只能是NSString型別的path（本地、遠端都可以），我嘗試使用相簿視訊url的absulutstring來初始化它，沒有成功，故改為使用系統自帶的MPMoviePlayerController。相關關鍵程式碼如下：

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
        _albumVideoInfos = [[NSMutableArray alloc] initWithCapacity:50];

        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playDidChangeNotification:) name:MPMoviePlayerPlaybackStateDidChangeNotification object:nil];

        [[NSNotificationCenter defaultCenter] addObserver:self
                                                 selector:@selector(playMovieFinishedCallback:)
                                                     name:MPMoviePlayerPlaybackDidFinishNotification
                                                   object:nil];
        //MPMoviePlayerController fullscreen 模式下，點選左上角的done按鈕，會呼叫exitFullScreen通知。
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(exitFullScreen:) name: MPMoviePlayerDidExitFullscreenNotification object:nil];
    }
    return self;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
    NSInteger row = indexPath.row;
    if (row < _albumVideoInfos.count) {
        AlbumVideoInfo *albumVideoInfo = _albumVideoInfos[row];
        if (!_moviePlayer) {
            _moviePlayer = [[MPMoviePlayerController alloc] initWithContentURL:albumVideoInfo.videoURL];
        }else{
            [_moviePlayer setContentURL:albumVideoInfo.videoURL];
        }
        _moviePlayer.view.frame = self.view.bounds;
        _moviePlayer.backgroundView.backgroundColor = [UIColor orangeColor];
        [self.view addSubview:_moviePlayer.view];

        _moviePlayer.controlStyle = MPMovieControlStyleFullscreen;
        _moviePlayer.shouldAutoplay = YES;
        _moviePlayer.repeatMode = MPMovieRepeatModeOne;
        [_moviePlayer setFullscreen:YES animated:YES];
        _moviePlayer.scalingMode = MPMovieScalingModeAspectFit;
        [_moviePlayer play];
    }
}

相關通知的處理：

#pragma mark - handle notification

- (void)playDidChangeNotification:(NSNotification *)notification {
    MPMoviePlayerController *moviePlayer = notification.object;
    MPMoviePlaybackState playState = moviePlayer.playbackState;
    if (playState == MPMoviePlaybackStateStopped) {
        NSLog(@"停止");
    } else if(playState == MPMoviePlaybackStatePlaying) {
        NSLog(@"播放");
    } else if(playState == MPMoviePlaybackStatePaused) {
        NSLog(@"暫停");
    }
}

- (void)playMovieFinishedCallback:(NSNotification *)notification{

    NSLog(@"finish");
}

- (void)exitFullScreen:(NSNotification *)notification{

    NSLog(@"exitFullScreen");
    [_moviePlayer stop];
    [_moviePlayer.view removeFromSuperview];
}

OK,重要的事情都說完了，but，在強調一下一個小細節。
//MPMoviePlayerController fullscreen 模式下，點選左上角的done按鈕，會呼叫exitFullScreen通知。