将 Image 添加到 UIImageView 及其标签

Question

我有一个带有标签 1,2,3,4...的多个 Imageview...

现在我想用它们各自的标签在那个 Imageviews 上加载图像。

例如：如果有 6 个 Imageview，则

for(int i=0;i<6;i++)
{
  imgView = [[UIImageView alloc] initWithFrame:CGRectMake(xpos+10,20, 75, 45)];
  xpos+=100;
  imgView.tag=i;

   if ([[msg_array objectAtIndex:i] valueForKey:@"Image"]) //Image is cached then assign it
    {
        imgView.image=[[msg_array objectAtIndex:i] valueForKey:@"Image"];
    }
    else //Image is not there download it..
    {
        if ([[msg_array objectAtIndex:i] valueForKey:@"Image"] length]!=0)
        {
            dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
                [self downloadImage_3:[[msg_array objectAtIndex:i] valueForKey:@"Merchant_SmallImage"] AtIndex:i];
            });
        }

    }

}


//Downloads Images asynchronously..
-(void)downloadImage_3:(NSString*)ImageUrl AtIndex:(int)i{

    if ([ImageUrl length]!=0)
    {
        UIImage *img = [[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:ImageUrl]]];
        NSLog(@"img = %@",img);
        imgView.image=img;
    }

}

写完后，图像正在下载（日志显示img 的一些编码值），但它没有应用于其各自的图像视图。

请帮助并提前致谢。

Answer 1

在将分配的图像视图添加到父视图的地方，它应该只在 for 循环内完成，每次将一个图像分配给图像视图时，您需要将此图像视图添加到父视图查看以使其显示，请检查。

Answer 2

试试下面的

 //change your download method like
-(void)downloadImage_3:(NSString*)ImageUrl forImageView :(UIImageView *)imgView
{
    if ([ImageUrl length]!=0)
    {
        UIImage *img = [[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:ImageUrl]]];

        dispatch_async(dispatch_get_main_queue(), ^{
            [imgView setImage:img];
        });
    }
}

//call your download method like below

 dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
            [self downloadImage_3:[[msg_array objectAtIndex:i] valueForKey:@"Merchant_SmallImage"] forImageView:imgView]; //pass your ImageView here
        });