将图片异步加载到自定义表格视图单元中 [英] Load images into custom table view cell asynchronously
问题描述
当前，我正在开发一个应用程序，其中已获取Facebook相册照片&显示为 使用表格视图&异步查看图库视图使用以下代码将图像放在表格视图单元格的按钮上:
Currently, I am developing an app in which I have fetch Facebook album photo & display it as gallery view asynchronously using Table view & put images on button of table view cell using below code:
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
NSLog(@"particulars..:%d",[particular count]);
int count=self.particular.count%3;
if(count==0)
{
return self.particular.count/3;
}
else
{
return (self.particular.count/3) +1;
}
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"Cell1";
CustomTableViewCell *cell = (CustomTableViewCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
{
[[NSBundle mainBundle] loadNibNamed:@"CustomTableViewCell" owner:self options:nil];
cell = customcell;
}
UIActivityIndicatorView *spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
dispatch_async(dispatch_get_global_queue(0,0), ^{
NSString *buttonurl=[self.particular objectAtIndex:((indexPath.row)*3)+0];
NSData * data = [[NSData alloc] initWithContentsOfURL: [NSURL URLWithString: buttonurl]];
if ( data == nil )
return;
dispatch_async(dispatch_get_main_queue(), ^{
UIImage *image = [UIImage imageWithData:data];
cell.accessoryType = UITableViewCellAccessoryNone;
cell.selectionStyle = UITableViewCellSelectionStyleNone;
cell.backgroundColor=[UIColor clearColor];
[cell.first setBackgroundImage:image forState:UIControlStateNormal] ;
[cell.first addTarget:self action:@selector(original:) forControlEvents:UIControlEventTouchUpInside];
[cell.first setContentMode:UIViewContentModeCenter] ;
cell.first.layer.cornerRadius = 10.0;
cell.first.layer.borderColor = [[UIColor grayColor]CGColor];
cell.first.layer.borderWidth = 1.0f;
cell.first.backgroundColor=[UIColor clearColor];
cell.first.tag = ((indexPath.row)*3)+1 ;
[spinner stopAnimating];
});
[data release];
});
if(((indexPath.row)*3)+3<[particular count])
{
UIActivityIndicatorView *spinner2 = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
UIActivityIndicatorView *spinner3 = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
//spinner2.backgroundColor=[UIColor blackColor];
CGRect frame= cell.second.frame;
spinner2.frame=frame;
//spinner2.frame=CGRectMake(112, y, 106, 106);
spinner2.hidesWhenStopped = YES;
[cell.second addSubview:spinner2];
[spinner2 startAnimating];
CGRect frame2= cell.third.frame;
spinner3.frame=frame2;
spinner3.hidesWhenStopped = YES;
[cell.third addSubview:spinner3];
[spinner3 startAnimating];
dispatch_async(dispatch_get_global_queue(0,0), ^
{
NSString *buttonurl=[self.particular objectAtIndex:((indexPath.row)*3)+1];
NSData * data = [[NSData alloc] initWithContentsOfURL: [NSURL URLWithString: buttonurl]];
NSString *buttonurl1=[self.particular objectAtIndex:((indexPath.row)*3)+2];
NSData * data1 = [[NSData alloc] initWithContentsOfURL: [NSURL URLWithString: buttonurl1]];
if ( data == nil )
return;
dispatch_async(dispatch_get_main_queue(), ^
{
UIImage *image = [UIImage imageWithData:data];
UIImage *image1 = [UIImage imageWithData:data1];
[cell.second setBackgroundImage:image forState:UIControlStateNormal] ;
[cell.second addTarget:self action:@selector(original:) forControlEvents:UIControlEventTouchUpInside];
[cell.second setContentMode:UIViewContentModeCenter] ;
cell.second.layer.cornerRadius = 10.0;
cell.second.layer.borderColor = [[UIColor grayColor]CGColor];
cell.second.layer.borderWidth = 1.0f;
cell.second.backgroundColor=[UIColor clearColor];
cell.second.tag = ((indexPath.row)*3)+2 ;
NSLog(@"cell.second.tag:%d",cell.second.tag);
[cell.third setBackgroundImage:image1 forState:UIControlStateNormal] ;
[cell.third addTarget:self action:@selector(original:) forControlEvents:UIControlEventTouchUpInside];
[cell.third setContentMode:UIViewContentModeCenter] ;
cell.third.layer.cornerRadius = 10.0;
cell.third.layer.borderColor = [[UIColor grayColor]CGColor];
cell.third.layer.borderWidth = 1.0f;
cell.third.backgroundColor=[UIColor clearColor];
cell.third.tag = ((indexPath.row)*3)+3 ;
NSLog(@"cell.third.tag:%d",cell.third.tag);
[spinner2 stopAnimating];
[spinner3 stopAnimating];
});
[data release];
});
}
else if(((indexPath.row)*3)+2<[particular count])
{
UIActivityIndicatorView *spinner2 = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
CGRect frame1 = CGRectMake(120, y, 106, 107);
spinner2.frame=frame1;
spinner2.hidesWhenStopped = YES;
[cell.second addSubview:spinner2];
[spinner2 startAnimating];
dispatch_async(dispatch_get_global_queue(0,0), ^
{
NSString *buttonurl=[self.particular objectAtIndex:((indexPath.row)*3)+1];
NSData * data = [[NSData alloc] initWithContentsOfURL: [NSURL URLWithString: buttonurl]];
if ( data == nil )
return;
dispatch_async(dispatch_get_main_queue(), ^
{
UIImage *image = [UIImage imageWithData:data];
[cell.second setBackgroundImage:image forState:UIControlStateNormal] ;
[cell.second addTarget:self action:@selector(original:) forControlEvents:UIControlEventTouchUpInside];
[cell.second setContentMode:UIViewContentModeCenter] ;
cell.second.layer.cornerRadius = 10.0;
cell.second.layer.borderColor = [[UIColor grayColor]CGColor];
cell.second.layer.borderWidth = 1.0f;
cell.second.backgroundColor=[UIColor clearColor];
cell.second.tag = ((indexPath.row)*3)+2 ;
NSLog(@"cell.second.tag:%d",cell.second.tag);
[spinner2 stopAnimating];
});
[data release];
});
}
else
{
cell.second.hidden = YES;
cell.third.hidden = YES;
}
y=y+106;
return cell;
}
这段代码对我来说很好用，但是问题是，当图像加载到表视图单元格包含的按钮中时，如果我们向下滚动，它会缓慢显示图像，但是此后，当我们向上滚动以查看之前加载的图像时，图像就会消失&它会从启动&开始再次加载花点时间.所以请告诉我我在代码中哪里做错了，或者我该如何解决呢?
This code is working fine for me but the problem is that when images load into button contain by table view cell then if we scroll down then it slowly show images but after that when we scroll up to see previously load images then images disappear & it again load from starting & take times.So please tell where i am doing mistake in code or how can I solve this?
推荐答案
我建议您使用此 AsyncImageView .我用过它，而且效果很好.调用此API:
I'd suggest you to use this AsyncImageView. I've used it and it work wonders. To call this API:
ASyncImage *img_EventImag = alloc with frame;
NSURL *url = yourPhotoPath;
[img_EventImage loadImageFromURL:photoPath];
[self.view addSubView:img_EventImage]; // In your case you'll add in your TableViewCell.
与使用UIImageView相同.简单易行，它可以为您完成大部分工作. AsyncImageView包括UIImageView上的一个简单类别(用于在iOS上异步加载和显示图像，以使它们不会锁定UI)以及UIImageView子类(用于更高级的功能). AsyncImageView使用URL，因此可以与本地或远程文件一起使用.
It's same as using UIImageView. Easy and it does most of the things for you. AsyncImageView includes both a simple category on UIImageView for loading and displaying images asynchronously on iOS so that they do not lock up the UI, and a UIImageView subclass for more advanced features. AsyncImageView works with URLs so it can be used with either local or remote files.
已加载/下载的图像缓存在内存中，并在出现内存警告时自动清除. AsyncImageView的运行独立于UIImage缓存，但是默认情况下，位于应用程序捆绑包根目录中的所有图像都将存储在UIImage缓存中，从而避免了缓存图像的任何重复.
Loaded/downloaded images are cached in memory and are automatically cleaned up in the event of a memory warning. The AsyncImageView operates independently of the UIImage cache, but by default any images located in the root of the application bundle will be stored in the UIImage cache instead, avoiding any duplication of cached images.
该库还可以用于独立于UIImageView加载和缓存图像，因为它可以直接访问基础的加载和缓存类.
The library can also be used to load and cache images independently of a UIImageView as it provides direct access to the underlying loading and caching classes.
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