iphone Three20如何添加到工程，以及如何添加删除图片的按钮。

     最近由于项目需要，需要做一个相册查看器来查看项目截图的图片。于是发现Three20的功能很强大，有自带的相册功能，于是就将其引用到工程里头来。

 首先是要下载three20并安装到工程里头。

   如果是想手动将three20添加到xcode4.2的话，可参照此链接：添加three20到xcode4.2教程

   如果想通过指令来将three20添加到xcode的话，可参照此链接通过指令将three20添加到xcode教程 

  通过指令来将three20添加到xcdoe时，操作比较快速。

但有几点需要注意。

1.尽量让下载的three20 与工程处于同一个目录，这样在后续的设置中会比较方便。

 2.如果PROJECT的名称与TARGETS的名称不一样的话，那通过指令执行时，需要执行如下指令。 

 3.接着按这些步骤把相册添加到自己的工程中去，将图片相册添加到工程。

3，如何在现有的程序中单击某一按钮，然后导航到three20的相册中。代码如下：如果想进一步的了解导航具体情况，那么可以参照此链接。导航具体教程

    - (IBAction)viewPhoto:(id)sender

{
     NSLog(@"%@",currentImageName);
    NSLog(@"%d",[currentImageName retainCount]);
    [[TTURLRequestQueue mainQueue] setMaxContentLength:0];
    TTNavigator *navigator = [TTNavigator navigator];
    navigator.window = [UIApplication sharedApplication].keyWindow;    
    TTURLMap *map = navigator.URLMap; 
    [map from:@"tt://appPhotos" toSharedViewController:[PhotoViewController class]];
   [navigator openURLAction:[TTURLAction actionWithURLPath:@"tt://appPhotos"]]; 
   

} 

 4，如果想从相册返回到原工程，可以在PhotoViewController.h 添加如下代码：

   4.1添加返回按钮到导航栏

      - (void) viewDidLoad {

    UIBarButtonItem *listViewBackBtn = [[UIBarButtonItem alloc] initWithTitle:@"test"
                                                                       style:UIBarButtonItemStylePlain        
                                                                       target:self 
                                                                       action:@selector(GoBack:)];  
    self.navigationItem.leftBarButtonItem = listViewBackBtn;   
    self.navigationItem.hidesBackButton = YES;   
    [listViewBackBtn release];
    self.photoSource = [PhotoSet samplePhotoSet];
    self.centerPhotoIndex = currentCaptureIndex;

   } 

   4.2添加返回按钮事件

         //返回到视频观看页面

-(void) GoBack:(id)sender{ 
    
    [[TTNavigator navigator] removeAllViewControllers];
}

   

    5.如何在相册中添加删除事件。

       5.1具体添加删除按钮以及事件可以参照此教程添加删除事件 、添加删除事件2

        5.2 删除后的图片中兴的事件。如下：

           //删除图片

- (void)deletePhotoAtIndex:(NSInteger)index
{
    NSMutableArray *muPhotos = [PhotoSet samplePhotoSet].photos;
    Photo *removePhoto = [muPhotos objectAtIndex:index];
    NSString *removePhotoName = removePhoto.caption;
    [self removePhotosOfDocuments:index removePhotoName:removePhotoName];
   // [muPhotos removeObjectAtIndex:index];
   self.photoSource = [PhotoSet samplePhotoSet];
   self.centerPhotoIndex = index;
   
}

- (void) removePhotosOfDocuments:(NSInteger)index removePhotoName:(NSString *) removePhotoName
{
    NSFileManager *fileManage = [NSFileManager defaultManager];
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask , YES) ;
    NSString *documentDirectory = [paths objectAtIndex:0];
    NSString *bigImagePath = [documentDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"BigImage/%@",removePhotoName]];
    NSString *smallImagePath = [documentDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"SmallImage/small_%@",removePhotoName]];
        NSError *error = nil;
    [fileManage removeItemAtPath:bigImagePath error:&error];
    [fileManage removeItemAtPath:smallImagePath error:&error];

} 

        5.3如果上传某一张图片，然后返回照片缩略图查看器，结果发现照片缩略图查看器中被删除的图片还在，这时需要修改TTPhotoViewController这个类的方法：红色部分为新添加的。这样才能保持相册缩略图的同步。

     

        TTPhotoViewController

- (void)showThumbnails {
  NSString* URL = [self URLForThumbnails];
  if (!_thumbsController) {
    if (URL) {
      // The photo source has a URL mapping in TTURLMap, so we use that to show the thumbs
      NSDictionary* query = [NSDictionary dictionaryWithObject:self forKey:@"delegate"];
      TTBaseNavigator* navigator = [TTBaseNavigator navigatorForView:self.view];
      _thumbsController = [[navigator viewControllerForURL:URL query:query] retain];
      [navigator.URLMap setObject:_thumbsController forURL:URL];

    } else {
      // The photo source had no URL mapping in TTURLMap, so we let the subclass show the thumbs
      _thumbsController = [[self createThumbsViewController] retain];
      _thumbsController.photoSource = _photoSource;
    }
  }

  if (URL) {
    TTOpenURLFromView(URL, self.view);

  } else {
    if ([self.navigationController isKindOfClass:[TTNavigationController class]]) {
        _thumbsController.photoSource = _photoSource;
      [(TTNavigationController*)self.navigationController
           pushViewController: _thumbsController
       animatedWithTransition: UIViewAnimationTransitionCurlDown];

    } else {
        _thumbsController.photoSource = _photoSource;
      [self.navigationController pushViewController:_thumbsController animated:YES];
    }
  }
}