Ios 如何在uitableviewcell中设置来自服务器的映像路径_Ios_Uitableview_Uiimageview

Ios 如何在uitableviewcell中设置来自服务器的映像路径

ios uitableview

Ios 如何在uitableviewcell中设置来自服务器的映像路径,ios,uitableview,uiimageview,Ios,Uitableview,Uiimageview,我正在制作一个应用程序，其中我正在从服务器获取数据，数据图像路径也即将到来，但当我将图像设置到tableview单元格时，应用程序将变得太重，可能b我没有正确设置图像下面是我的示例代码thanx：）不要使用imageWithData:设置图像。它是同步的，会使你的应用程序运行缓慢而不是那种用途您只需执行以下操作：将SDWebImage文件夹转储到项目中导入UIImageView+WebCache.h 使用以下内容设置图像：sd\u setImageWithURL: 或由。从复制的代码

我正在制作一个应用程序，其中我正在从服务器获取数据，数据图像路径也即将到来，但当我将图像设置到tableview单元格时，应用程序将变得太重，可能b我没有正确设置图像下面是我的示例代码thanx：）

不要使用

imageWithData:

设置图像。它是同步的，会使你的应用程序运行缓慢

而不是那种用途

您只需执行以下操作：

将SDWebImage文件夹转储到项目中

导入

UIImageView+WebCache.h

使用以下内容设置图像：

sd\u setImageWithURL:

或

由。从复制的代码

首先实现以下方法

- (void)downloadImageWithURL:(NSURL *)url completionBlock:(void (^)(BOOL succeeded, UIImage *image))completionBlock
{
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    [NSURLConnection sendAsynchronousRequest:request
                                       queue:[NSOperationQueue mainQueue]
                           completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
                               if ( !error )
                               {
                                    UIImage *image = [[UIImage alloc] initWithData:data];
                                    completionBlock(YES,image);
                                } else{
                                    completionBlock(NO,nil);
                                }
                           }];
}

然后在您的

cellforrowatinexpath

[self downloadImageWithURL:your_url completionBlock:^(BOOL succeeded, UIImage *image) {
            if (succeeded) {
                // change the image in the cell
                cell.imageView.image = image;


            }
        }];

不要使用

imageWithData:

设置图像。它是同步的，会使你的应用程序运行缓慢

而不是那种用途

您只需执行以下操作：

将SDWebImage文件夹转储到项目中

导入

UIImageView+WebCache.h

使用以下内容设置图像：

sd\u setImageWithURL:

或

由。从复制的代码

首先实现以下方法

- (void)downloadImageWithURL:(NSURL *)url completionBlock:(void (^)(BOOL succeeded, UIImage *image))completionBlock
{
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    [NSURLConnection sendAsynchronousRequest:request
                                       queue:[NSOperationQueue mainQueue]
                           completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
                               if ( !error )
                               {
                                    UIImage *image = [[UIImage alloc] initWithData:data];
                                    completionBlock(YES,image);
                                } else{
                                    completionBlock(NO,nil);
                                }
                           }];
}

然后在您的

cellforrowatinexpath

[self downloadImageWithURL:your_url completionBlock:^(BOOL succeeded, UIImage *image) {
            if (succeeded) {
                // change the image in the cell
                cell.imageView.image = image;


            }
        }];

首先，您正在调用dataWithContentsOfURL:函数，这将使应用程序无响应，因为您正在主线程上调用它。要使其具有响应性，您需要在YourCell中创建一个自定义单元格，并在YourCell.h中声明一个方法

@interface YourCell : UITableViewCell
{
    UIImage *_cImage;
}

- (void)downloadImageFromURL:(NSURL *)imageUrl;
@end

现在在你的牢房里。m你需要这样做：

- (void)downloadImageFromURL:(NSURL *)imageUrl
{
    if (_cImage != nil)
    {
        self.imageView.image = _cImage;
    }
    else
    {
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        _cImage = [UIImage imageWithData:[NSData dataWithContentsOfURL:imageUrl]];

        dispatch_sync(dispatch_get_main_queue(), ^{
                self.imageView.image = _cImage;
            });
        });
    }
}

现在从cellForRowAtIndexPath开始：您只需要调用单元格的downloadImageFromURL:函数，并将imageUrl传递给它，然后由单元格负责下载和显示图像

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier= @"YourCell";
    YourCell *cell = (YourCell *)[self.activitiesTableView_ dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil)
    {
        cell = [[[NSBundle mainBundle] loadNibNamed:@"YourCell" owner:self options:nil] objectAtIndex:0];
    }

    // Set your UILabels as before.....

    NSString *imagePath=[[self.inboxmessagesarray objectAtIndex:indexPath.row] objectForKey:@"offerPhoto"];
    [cell downloadImageFromURL:[NSURL URLWithString:imagePath]];

    return cell;        
}

如果您有任何问题，请告诉我。

首先，您正在使用contentsofURL:函数调用数据，这将使应用程序无响应，因为您是在主线程上调用它的。要使其具有响应性，您需要在YourCell中创建一个自定义单元格，并在YourCell.h中声明一个方法

@interface YourCell : UITableViewCell
{
    UIImage *_cImage;
}

- (void)downloadImageFromURL:(NSURL *)imageUrl;
@end

UIImageView *img1 = (UIImageView *)[cell viewWithTag:104];
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
        dispatch_async(dispatch_get_main_queue(), ^{
            img1.image = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:img]]];
        });
    });

现在在你的牢房里。m你需要这样做：

- (void)downloadImageFromURL:(NSURL *)imageUrl
{
    if (_cImage != nil)
    {
        self.imageView.image = _cImage;
    }
    else
    {
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        _cImage = [UIImage imageWithData:[NSData dataWithContentsOfURL:imageUrl]];

        dispatch_sync(dispatch_get_main_queue(), ^{
                self.imageView.image = _cImage;
            });
        });
    }
}

现在从cellForRowAtIndexPath开始：您只需要调用单元格的downloadImageFromURL:函数，并将imageUrl传递给它，然后由单元格负责下载和显示图像

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier= @"YourCell";
    YourCell *cell = (YourCell *)[self.activitiesTableView_ dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil)
    {
        cell = [[[NSBundle mainBundle] loadNibNamed:@"YourCell" owner:self options:nil] objectAtIndex:0];
    }

    // Set your UILabels as before.....

    NSString *imagePath=[[self.inboxmessagesarray objectAtIndex:indexPath.row] objectForKey:@"offerPhoto"];
    [cell downloadImageFromURL:[NSURL URLWithString:imagePath]];

    return cell;        
}

如果你有任何问题，请告诉我

UIImageView *img1 = (UIImageView *)[cell viewWithTag:104];
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
        dispatch_async(dispatch_get_main_queue(), ^{
            img1.image = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:img]]];
        });
    });

发送图像的异步请求。在图像加载之前，这样做不会阻塞UI

发送图像的异步请求。在图像加载之前，这样做不会阻塞您的UI。

尝试下面的代码，希望这对您有所帮助

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
 {
   __block  tablecellTableViewCell *cell= [self.activitiesTableView_ dequeueReusableCellWithIdentifier:tableviewidentifier];
   if(cell==nil)
   {
      cell = [[tablecellTableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:tableviewidentifier];
   }
   if(indexPath.row == [self tableView:tableView numberOfRowsInSection:indexPath.section] - 1)
   {
      // [[cell textLabel] setText:@"Load more records"];
   }
   UILabel *valuedate = (UILabel *)[cell viewWithTag:21];
   UILabel *msg = (UILabel *)[cell viewWithTag:22];
   UILabel *date = (UILabel *)[cell viewWithTag:23];
   UILabel *time = (UILabel *)[cell viewWithTag:24];
   valuedate.text=[[self.inboxmessagesarray objectAtIndex:indexPath.row]objectForKey:@"offerTitle"];
   msg.text=@"How are you?";

   dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{     
   NSString *img=[[self.inboxmessagesarray objectAtIndex:indexPath.row]objectForKey:@"offerPhoto"];// here i am getting image path
   NSURL *url = [NSURL URLWithString:img];
   NSData * imageData = [NSData dataWithContentsOfURL:url];
   UIImage *image = [UIImage imageWithData:imageData];

   dispatch_sync(dispatch_get_main_queue(), ^{ //in main thread update the image
    cell.imageView.image = image;
    cell.textLabel.text = @""; //add this update will reflect the changes 
    });
  });
 return cell;
}

编辑为了重用下载的图像，你可以将它们保存在磁盘上，也可以只将它们保存在一些地方，例如在字典中，以便临时使用

在下面的代码中，我使用了一个示例字典，并使用row作为键下载图像

@interface ViewController ()
{
    NSMutableDictionary *imagesDictionary; //lets declare a mutable dictionary to hold images 
}

  - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
  {
     __block  tablecellTableViewCell *cell= [self.activitiesTableView_ dequeueReusableCellWithIdentifier:tableviewidentifier];
    if(cell==nil)
    {
       cell = [[tablecellTableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:tableviewidentifier];
    }
   if(indexPath.row == [self tableView:tableView numberOfRowsInSection:indexPath.section] - 1)
   {
      // [[cell textLabel] setText:@"Load more records"];
   }
   __block NSString *row = [NSString stringWithFormat:@"%d",indexPath.row]; //add this

   UILabel *valuedate = (UILabel *)[cell viewWithTag:21];
   UILabel *msg = (UILabel *)[cell viewWithTag:22];
   UILabel *date = (UILabel *)[cell viewWithTag:23];
   UILabel *time = (UILabel *)[cell viewWithTag:24];
   // valuedate.text=[[self.inboxmessagesarray objectAtIndex:indexPath.row]objectForKey:@"offerTitle"];
   msg.text=@"How are you?";
   if(![[imagesDictionary allKeys] containsObject:row]) //if image not found download and add it to dictionary
   {
       dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
       // NSString *img=[[self.inboxmessagesarray objectAtIndex:indexPath.row]objectForKey:@"offerPhoto"];// here i am getting image path
        NSURL *url = [NSURL URLWithString:img];
        NSData * imageData = [NSData dataWithContentsOfURL:url];
        UIImage *image = [UIImage imageWithData:imageData];

        dispatch_sync(dispatch_get_main_queue(), ^{ //in main thread update the image
             [imagesDictionary setObject:image forKey:row]; //sorry, while editing to your code i forgot to add this 
            cell.imageView.image = image;
            cell.textLabel.text = @""; //add this update will reflect the changes
             NSLog(@"loading and addig to dictionary");
        });
    });
  }
  else
  {
    cell.imageView.image = [imagesDictionary objectForKey:row];
    NSLog(@"retriving from dictioary");
  }
  return cell;
}

在这个方法中，只需初始化它

- (void)viewDidLoad {
    [super viewDidLoad];
    // rest of your code
    //...........
    //
    imagesDictionary = [[NSMutableDictionary alloc]init]; //initilise 
 }

在索引中，此方法只需将下载的图像作为键添加到对应行的字典中

@interface ViewController ()
{
    NSMutableDictionary *imagesDictionary; //lets declare a mutable dictionary to hold images 
}

  - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
  {
     __block  tablecellTableViewCell *cell= [self.activitiesTableView_ dequeueReusableCellWithIdentifier:tableviewidentifier];
    if(cell==nil)
    {
       cell = [[tablecellTableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:tableviewidentifier];
    }
   if(indexPath.row == [self tableView:tableView numberOfRowsInSection:indexPath.section] - 1)
   {
      // [[cell textLabel] setText:@"Load more records"];
   }
   __block NSString *row = [NSString stringWithFormat:@"%d",indexPath.row]; //add this

   UILabel *valuedate = (UILabel *)[cell viewWithTag:21];
   UILabel *msg = (UILabel *)[cell viewWithTag:22];
   UILabel *date = (UILabel *)[cell viewWithTag:23];
   UILabel *time = (UILabel *)[cell viewWithTag:24];
   // valuedate.text=[[self.inboxmessagesarray objectAtIndex:indexPath.row]objectForKey:@"offerTitle"];
   msg.text=@"How are you?";
   if(![[imagesDictionary allKeys] containsObject:row]) //if image not found download and add it to dictionary
   {
       dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
       // NSString *img=[[self.inboxmessagesarray objectAtIndex:indexPath.row]objectForKey:@"offerPhoto"];// here i am getting image path
        NSURL *url = [NSURL URLWithString:img];
        NSData * imageData = [NSData dataWithContentsOfURL:url];
        UIImage *image = [UIImage imageWithData:imageData];

        dispatch_sync(dispatch_get_main_queue(), ^{ //in main thread update the image
             [imagesDictionary setObject:image forKey:row]; //sorry, while editing to your code i forgot to add this 
            cell.imageView.image = image;
            cell.textLabel.text = @""; //add this update will reflect the changes
             NSLog(@"loading and addig to dictionary");
        });
    });
  }
  else
  {
    cell.imageView.image = [imagesDictionary objectForKey:row];
    NSLog(@"retriving from dictioary");
  }
  return cell;
}

试试下面的代码，希望对你有所帮助

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
 {
   __block  tablecellTableViewCell *cell= [self.activitiesTableView_ dequeueReusableCellWithIdentifier:tableviewidentifier];
   if(cell==nil)
   {
      cell = [[tablecellTableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:tableviewidentifier];
   }
   if(indexPath.row == [self tableView:tableView numberOfRowsInSection:indexPath.section] - 1)
   {
      // [[cell textLabel] setText:@"Load more records"];
   }
   UILabel *valuedate = (UILabel *)[cell viewWithTag:21];
   UILabel *msg = (UILabel *)[cell viewWithTag:22];
   UILabel *date = (UILabel *)[cell viewWithTag:23];
   UILabel *time = (UILabel *)[cell viewWithTag:24];
   valuedate.text=[[self.inboxmessagesarray objectAtIndex:indexPath.row]objectForKey:@"offerTitle"];
   msg.text=@"How are you?";

   dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{     
   NSString *img=[[self.inboxmessagesarray objectAtIndex:indexPath.row]objectForKey:@"offerPhoto"];// here i am getting image path
   NSURL *url = [NSURL URLWithString:img];
   NSData * imageData = [NSData dataWithContentsOfURL:url];
   UIImage *image = [UIImage imageWithData:imageData];

   dispatch_sync(dispatch_get_main_queue(), ^{ //in main thread update the image
    cell.imageView.image = image;
    cell.textLabel.text = @""; //add this update will reflect the changes 
    });
  });
 return cell;
}

编辑为了重用下载的图像，你可以将它们保存在磁盘上，也可以只将它们保存在一些地方，例如在字典中，以便临时使用

在下面的代码中，我使用了一个示例字典，并使用row作为键下载图像

@interface ViewController ()
{
    NSMutableDictionary *imagesDictionary; //lets declare a mutable dictionary to hold images 
}

  - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
  {
     __block  tablecellTableViewCell *cell= [self.activitiesTableView_ dequeueReusableCellWithIdentifier:tableviewidentifier];
    if(cell==nil)
    {
       cell = [[tablecellTableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:tableviewidentifier];
    }
   if(indexPath.row == [self tableView:tableView numberOfRowsInSection:indexPath.section] - 1)
   {
      // [[cell textLabel] setText:@"Load more records"];
   }
   __block NSString *row = [NSString stringWithFormat:@"%d",indexPath.row]; //add this

   UILabel *valuedate = (UILabel *)[cell viewWithTag:21];
   UILabel *msg = (UILabel *)[cell viewWithTag:22];
   UILabel *date = (UILabel *)[cell viewWithTag:23];
   UILabel *time = (UILabel *)[cell viewWithTag:24];
   // valuedate.text=[[self.inboxmessagesarray objectAtIndex:indexPath.row]objectForKey:@"offerTitle"];
   msg.text=@"How are you?";
   if(![[imagesDictionary allKeys] containsObject:row]) //if image not found download and add it to dictionary
   {
       dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
       // NSString *img=[[self.inboxmessagesarray objectAtIndex:indexPath.row]objectForKey:@"offerPhoto"];// here i am getting image path
        NSURL *url = [NSURL URLWithString:img];
        NSData * imageData = [NSData dataWithContentsOfURL:url];
        UIImage *image = [UIImage imageWithData:imageData];

        dispatch_sync(dispatch_get_main_queue(), ^{ //in main thread update the image
             [imagesDictionary setObject:image forKey:row]; //sorry, while editing to your code i forgot to add this 
            cell.imageView.image = image;
            cell.textLabel.text = @""; //add this update will reflect the changes
             NSLog(@"loading and addig to dictionary");
        });
    });
  }
  else
  {
    cell.imageView.image = [imagesDictionary objectForKey:row];
    NSLog(@"retriving from dictioary");
  }
  return cell;
}

在这个方法中，只需初始化它

- (void)viewDidLoad {
    [super viewDidLoad];
    // rest of your code
    //...........
    //
    imagesDictionary = [[NSMutableDictionary alloc]init]; //initilise 
 }

在索引中，此方法只需将下载的图像作为键添加到对应行的字典中

@interface ViewController ()
{
    NSMutableDictionary *imagesDictionary; //lets declare a mutable dictionary to hold images 
}

  - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
  {
     __block  tablecellTableViewCell *cell= [self.activitiesTableView_ dequeueReusableCellWithIdentifier:tableviewidentifier];
    if(cell==nil)
    {
       cell = [[tablecellTableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:tableviewidentifier];
    }
   if(indexPath.row == [self tableView:tableView numberOfRowsInSection:indexPath.section] - 1)
   {
      // [[cell textLabel] setText:@"Load more records"];
   }
   __block NSString *row = [NSString stringWithFormat:@"%d",indexPath.row]; //add this

   UILabel *valuedate = (UILabel *)[cell viewWithTag:21];
   UILabel *msg = (UILabel *)[cell viewWithTag:22];
   UILabel *date = (UILabel *)[cell viewWithTag:23];
   UILabel *time = (UILabel *)[cell viewWithTag:24];
   // valuedate.text=[[self.inboxmessagesarray objectAtIndex:indexPath.row]objectForKey:@"offerTitle"];
   msg.text=@"How are you?";
   if(![[imagesDictionary allKeys] containsObject:row]) //if image not found download and add it to dictionary
   {
       dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
       // NSString *img=[[self.inboxmessagesarray objectAtIndex:indexPath.row]objectForKey:@"offerPhoto"];// here i am getting image path
        NSURL *url = [NSURL URLWithString:img];
        NSData * imageData = [NSData dataWithContentsOfURL:url];
        UIImage *image = [UIImage imageWithData:imageData];

        dispatch_sync(dispatch_get_main_queue(), ^{ //in main thread update the image
             [imagesDictionary setObject:image forKey:row]; //sorry, while editing to your code i forgot to add this 
            cell.imageView.image = image;
            cell.textLabel.text = @""; //add this update will reflect the changes
             NSLog(@"loading and addig to dictionary");
        });
    });
  }
  else
  {
    cell.imageView.image = [imagesDictionary objectForKey:row];
    NSLog(@"retriving from dictioary");
  }
  return cell;
}

除了这个还有别的选择吗？但我建议SDWebImage。它被广泛使用，易于理解。任何其他内置选项？？非常有用的库。。Thnx除此之外还有其他选项吗？但我建议SDWebImage。它被广泛使用，易于理解。任何其他内置选项？？非常有用的库。。Thnx请您也提到行indexpath方法的单元格好吗？@MishalAwan函数已添加到帖子中。@MishalAwan如果您觉得帖子有用，请投赞成票。谢谢。请您也提到行indexpath方法的单元格好吗？@MishalAwan函数已添加到帖子中。@MishalAwan如果您觉得帖子有用，请投赞成票。谢谢这是为了什么？上面的代码可以用于发送异步请求，不像您使用的发送同步请求的代码。发送同步请求会完全阻塞UI，直到下载整个图像。比方说，如果您的internet速度较慢，则会加载除图像之外的整个ui（如果您使用Async request）。什么是fromimage.image it id在我这边出现错误？这是为了什么？上面的代码可用于发送异步请求，而不是发送同步请求的代码。发送同步请求会完全阻塞UI，直到下载整个图像。比方说，如果您的internet速度较慢，则会加载整个ui，如果您使用异步请求，则会加载除图像之外的所有图像。而什么是fromimage.image it id在我这边给出错误？NSString*img的值是多少。添加一个作为参考，您可以从NSLog中获得。检查我编辑的答案。。NSString*img的值是多少。添加一个作为参考，您可以从NSLog获得。检查我编辑的答案。评论不用于扩展讨论；此对话已结束。评论不用于扩展讨论；这段对话已经结束。