如何制作一个简单的多线程？

发布于 2024-11-17 02:12:02 字数 451 浏览 0 评论 0原文

好的，现在我正在制作一个像餐厅查找器这样的移动应用程序，我想显示餐厅的照片

示例：restaurant x

这是一个代码：

if (ImageToDisplay != nil)
{
   NSData * imageData = [[[NSData alloc] initWithContentsOfURL: [NSURL URLWithString: ImageToDisplay.URL]]autorelease];
   ImageForRestaurant.image = [UIImage imageWithData: imageData];
}

问题是这个下载过程图片可能需要太长时间。所以我希望该进程在不同的线程上运行。

这样之后的代码就可以运行，而不必等待这一代码完成。

我怎样才能这样做呢？

原文

Okay, now I was making a mobile application like restaurant finder, I want to show a photo of the restaurant

the example : restaurant x <image x>

It's a code:

if (ImageToDisplay != nil)
{
   NSData * imageData = [[[NSData alloc] initWithContentsOfURL: [NSURL URLWithString: ImageToDisplay.URL]]autorelease];
   ImageForRestaurant.image = [UIImage imageWithData: imageData];
}

The problem is this process of downloading pictures may take too long. So I want the process to be run on a different thread.

That way the code after that can run without having to wait this one to finish.

How can I do so?

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上课铃就是安魂曲 2024-11-24 02:12:02

 if (ImageToDisplay != nil) {
  [self performSelectorInBackground:@selector(loadImage:) object:ImageToDisplay];
}

- (void)loadImage:(ImageToDisplay *)image { //Background method
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
    NSData * imageData = [[[NSData alloc] initWithContentsOfURL: [NSURL URLWithString: ImageToDisplay.URL]]autorelease];
    [self performSelectorOnMainThread:@selector(setImageForRestaurant:) withObject:imageData waitUntilDone:NO];
    [pool release];
}

- (void)setImageForRestaurant:(NSData *)imageData { //Change UI in main thread
    ImageForRestaurant.image = [UIImage imageWithData: imageData];
}

我刚刚介绍了多线程的基础知识；我想这会达到你的目的

 if (ImageToDisplay != nil) {
  [self performSelectorInBackground:@selector(loadImage:) object:ImageToDisplay];
}

- (void)loadImage:(ImageToDisplay *)image { //Background method
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
    NSData * imageData = [[[NSData alloc] initWithContentsOfURL: [NSURL URLWithString: ImageToDisplay.URL]]autorelease];
    [self performSelectorOnMainThread:@selector(setImageForRestaurant:) withObject:imageData waitUntilDone:NO];
    [pool release];
}

- (void)setImageForRestaurant:(NSData *)imageData { //Change UI in main thread
    ImageForRestaurant.image = [UIImage imageWithData: imageData];
}

I've just included basics in multi-threading; I guess it will serve your purpose

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