在 iOS 的 icarousel 中使用 AsyncImageView 的问题

Posted 2023-03-10

【中文标题】在 iOS 的 icarousel 中使用 AsyncImageView 的问题

【英文标题】：Issue in Using AsyncImageView in icarousel in iOS

【发布时间】：2012-10-31 10:30:39

【问题描述】：

我开发了一个使用 Asyncimageview 和 iCarousel 的应用程序。但我的问题是，当我尝试从 url 加载图像时，我的 iCarousel 的每个视图中只加载活动指示器并且没有加载任何图像。这是我的代码

  - (UIView *)carousel:(iCarousel *)carousel viewForItemAtIndex:(NSUInteger)index reusingView:(AsyncImageView *)view
 
if (view == nil
 
  AsyncImageView * view = [[[AsyncImageView alloc]initWithFrame:CGRectMake(0, 0, 300, 280)] autorelease];
view.image=[UIImage imageNamed:@"infobg.png"];
view.imageURL=[imageURLs objectAtIndex:index];

return view;

【问题讨论】：

尝试放置 NSLog(@"%@", [imageURLs objectAtIndex:index]);并检查它不为零。

另外，NeverBe 下面的回答是正确的，即使它没有解决您的问题。您编写的代码将无法正常工作。

【参考方案1】：

按照这些步骤可能是由于以下原因您可能会遇到此问题

-- 检查你的 imageURLs 数组是否有 iCarousel 下的对象不是...如果它为 null 你可能有这种问题......

-- 做数组分配和添加对象

 - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil 

方法，因为如果您在 viewDidLoad 下的数组中添加对象，它将不起作用，因为轮播视图在 viewDidLoad 方法之前首先加载..

-- 如果您的数组元素即使在按照此代码执行这些步骤之后仍然存在。

- (UIView *)carousel:(iCarousel *)carousel viewForItemAtIndex:(NSUInteger)index reusingView:(AsyncImageView *)view

view = [[[AsyncImageView alloc]initWithFrame:CGRectMake(0, 0, 300, 280)] autorelease];

view.image=[UIImage imageNamed:@"infobg.png"];
view.imageURL=[imageURLs objectAtIndex:index];

//NSLog(@"%@",imageURLs)//check imageURLs having object

if(view ==nil)

    [[AsyncImageLoader sharedLoader]cancelLoadingImagesForTarget:view];

return view;

它会帮助你..

【参考方案2】：

细胞应该重复使用

- (UIView *)carousel:(iCarousel *)carousel viewForItemAtIndex:(NSUInteger)index reusingView:(AsyncImageView *)view

 
if (view == nil) 
 view = [[[AsyncImageView alloc]initWithFrame:CGRectMake(0, 0, 300, 280)] autorelease];

// dont forget stop previous loading -cancelLoadingURL:target:

 view.image=[UIImage imageNamed:@"infobg.png"];
 view.imageURL=[imageURLs objectAtIndex:index];

 return view;

你也应该停止之前启动的

【讨论】：

我仍然有同样的问题，只有指标加载，如果我使用 [AsyncImageLoader sharedLoader] cancelLoadingImagesForTarget:view];甚至活动指示器都没有显示...有什么想法吗？

@NeverBe 你能在上面的代码中解释如何重用单元格并停止以前的加载方法......我很久以前也有同样的问题，但切换到另一种方法......

@VishnuPrasath 您应该在新图像加载之前使用正确的参数调用 cancelLoadingURL:target

@jai 您是否尝试在浏览器中打开这些链接？

@NeverBe ya 这些图像在浏览器中运行良好...我使用了 cancelloadingURL:[imageURLs objectAtIndex:index] target:view 这是正确的方法吗？

【参考方案3】：

- (void)viewDidLoad

    [super viewDidLoad];

    User_Id=@"[e-mail]";

    NSString *Post=[NSString stringWithFormat:@"email=%@",User_Id];
    NSData *PostData = [Post dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:NO];
    NSString *PostLengh=[NSString stringWithFormat:@"%d",[Post length]];
    NSURL *Url=[NSURL URLWithString:[NSString stringWithFormat:@"%@fetch_all_user_updates.php",ServerPath]];

    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:Url     cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0];
    [request setHTTPMethod:@"POST"];
    [request setValue:PostLengh forHTTPHeaderField:@"Content-Lenght"];
    [request setHTTPBody:PostData];

    NSData *ReturnData =[NSURLConnection sendSynchronousRequest:request returningResponse:Nil error:Nil];
    NSString *Response = [[NSString alloc] initWithData:ReturnData encoding:NSUTF8StringEncoding];
    Response = [Response stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
    NSMutableArray *JSON_Array=[Response JSONValue];

// NSlog(@"%@", JSON_Array);
// textfield.text=[[JSON_Array valueforKey:@"email"]objectAtIndex:0];
// load images from database at local host
/*
NSLog(@"%@",[NSString stringWithFormat:@"%@/Images/%@",serverScriptpath,[[jsonarray valueForKey:@"image"]objectAtIndex:0]]);
NSURL *img_url=[NSURL URLWithString:[NSString stringWithFormat:@"%@/Images/%@",
                                     serverScriptpath,[[jsonarray valueForKey:@"image"]objectAtIndex:0]]];

NSURLRequest *request1=[NSURLRequest requestWithURL:img_url];
[Img_profilepic setImageWithURLRequest:request1 placeholderImage:[UIImage imageNamed:@".png"] success:^(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image) 

 failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error) 

];
*/


    if (JSON_Array>0)
    
        Array_Image_Name=[JSON_Array valueForKey:@"image_name"];
        [Array_Image_Name retain];
    
    else
    
        UIAlertView *Alert=[[UIAlertView alloc]initWithTitle:@"Failure" message:@"Error To Load Image" delegate:Nil cancelButtonTitle:@"OK" otherButtonTitles:Nil, nil];
        [Alert show];
        [Alert release];
    


- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView

    return 1;


- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section

    return Array_Image_Name.count;


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell;
    cell=nil;
    if (cell == nil)
    
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    

    AsyncImageView *Load_Image=[[AsyncImageView alloc]initWithFrame:CGRectMake(20, 10, 280, 100)];
    Load_Image.imageURL=[NSURL URLWithString:[NSString stringWithFormat:@"%@/Images/%@",ServerPath,[Array_Image_Name objectAtIndex:indexPath.row]]];
    Load_Image.showActivityIndicator=YES;
    [cell.contentView addSubview:Load_Image];
    return cell;

【参考方案4】：

AsyncImageView *asyncImage = [[AsyncImageView alloc] initWithFrame:CGRectMake(0.0f, 1.0f, 320.0f, 174.0f)];
NSString *imgUrlString = photobig1;
while ([imgUrlString rangeOfString:@" "].location != NSNotFound) 
    imgUrlString = [imgUrlString stringByReplacingOccurrencesOfString:@" " withString:@""];

UIImageView *imageview = [[UIImageView alloc]initWithImage:[UIImage imageNamed:@"Loading Image.png"]];
[asyncImage addSubview:imageview];
asyncImage.tag = 999;
NSString *webStr = [NSString stringWithFormat:@"%@",imgUrlString];
NSURL *imageUrl = [[NSURL alloc] initWithString:[webStr stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding]];
[asyncImage loadImageFromURL:imageUrl];
[asyncImage setBackgroundColor:[UIColor clearColor]];
asyncImage.userInteractionEnabled = NO;

  [scrollView addSubview:asyncImage];