ios 4 新特性--------AssetsLibrary

最新推荐文章于 2024-06-13 07:45:00 发布

原创最新推荐文章于 2024-06-13 07:45:00 发布 · 115 阅读

0 ·

CC 4.0 BY-SA版权

ios 4 新特性专栏收录该内容

5 篇文章

订阅专栏

本文介绍如何在iOS应用中使用MediaPlayer框架播放视频，并通过AssetsLibrary框架读取和管理照片与视频文件。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

一：assetslibrary

读取photo 和video

1：add AssetsLibrary

2：#import <AssetsLibrary/AssetsLibrary.h>

3：

-(IBAction) getStats {
 __block int numberOfGroups = 0;
 __block int numberOfAssets = 0;
 
 // Create the object to represent the library
 ALAssetsLibrary *assetsLibrary = [[ALAssetsLibrary alloc] init];
 
 // What kind of groups are you interested in?
 NSUInteger groupTypes = ALAssetsGroupAll;
   
 // Create the block to enumerate through the groups
 ALAssetsLibraryGroupsEnumerationResultsBlock listGroupBlock = 
 ^(ALAssetsGroup *group, BOOL *stop) {
  // this block will be called for every group, and ONCE MORE!
  // so first, test if there's a real group being passed in:
  if (group) {
   // add to the totals
   numberOfGroups++;
   numberOfAssets += group.numberOfAssets;
   // output some info about the group
   NSLog(@"The name of the group is, %@",
     [group valueForProperty:ALAssetsGroupPropertyName]);
  } else {
   // the group object is nil, must mean we're done enumerating!
   // create an output message.
   NSString *message = [NSString 
         stringWithFormat:@"There are %d groups with %d total assets.",
         numberOfGroups,numberOfAssets];
   
   UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Asset Stats!" 
               message:message 
                 delegate:nil 
              cancelButtonTitle:@"Okay" 
              otherButtonTitles:nil];
   [alert show];
   [alert release];
   
  }

 };
   
 // create the failure block
 ALAssetsLibraryAccessFailureBlock failBlock = ^(NSError *error) {
  NSLog(@"Error:%@", [error localizedDescription]); 
 };
 
 // now enumerate through the groups, using the created blocks
 [assetsLibrary enumerateGroupsWithTypes:groupTypes 
         usingBlock:listGroupBlock 
          failureBlock:failBlock];
 
 [assetsLibrary release];
}

二：在你的app 中播放视频

1：add MediaPlayer

2：#import <MediaPlayer/MediaPlayer.h>

3：

-(IBAction) buttonTapped: (id) sender {
    NSString *path = [[NSBundle mainBundle] 
       pathForResource:@"water" ofType:@"m4v"];
 
 player = [[MPMoviePlayerViewController alloc]
     initWithContentURL:[NSURL fileURLWithPath:path]];

 [[NSNotificationCenter defaultCenter]
  addObserver:self selector:@selector(movieFinishedPlaying:)
  name:MPMoviePlayerPlaybackDidFinishNotification 
  object:[player moviePlayer]];

 
 [self presentMoviePlayerViewControllerAnimated:player];
 
}

-(void) movieFinishedPlaying: (NSNotification *) note {
 [[NSNotificationCenter defaultCenter]
  removeObserver:self
  name:MPMoviePlayerPlaybackDidFinishNotification 
  object:[player moviePlayer]];
 
 [player release];
}