如何在不阻止我的iphone应用程序中的用户界面的情况下运行流程 [英] How do I run a process without blocking user interface in my iphone app
问题描述
我正在访问iphone上的照片库,导入我在应用程序中选择的图片需要很长时间,如何在辅助线程上运行该进程,或者我使用什么解决方案来阻止用户接口?
I am accessing the photo library on the iphone and it takes a long time to import the pictures i select in my application, how do i run the process on a secondary thread , or what solution do i use to not block the user interface?
推荐答案
我在这里使用performSelectOnBackground或GCD对示例代码做了完整的解释:
I did a full explanation with sample code using performSelectOnBackground or GCD here:
以下是该帖子的示例代码部分(减去他的具体问题:
Here's the sample code portion of that post (minus his specific problems:
performSelectorInBackground示例:
在这个片段中,我有一个调用长时间运行工作的按钮,一个状态标签,我添加了一个滑块以显示我可以bg工作完成后移动滑块。
In this snippet, I have a button which invokes the long running work, a status label, and I added a slider to show I can move the slider while the bg work is done.
// on click of button
- (IBAction)doWork:(id)sender
{
[[self feedbackLabel] setText:@"Working ..."];
[[self doWorkButton] setEnabled:NO];
[self performSelectorInBackground:@selector(performLongRunningWork:) withObject:nil];
}
- (void)performLongRunningWork:(id)obj
{
// simulate 5 seconds of work
// I added a slider to the form - I can slide it back and forth during the 5 sec.
sleep(5);
[self performSelectorOnMainThread:@selector(workDone:) withObject:nil waitUntilDone:YES];
}
- (void)workDone:(id)obj
{
[[self feedbackLabel] setText:@"Done ..."];
[[self doWorkButton] setEnabled:YES];
}
GCD示例:
// on click of button
- (IBAction)doWork:(id)sender
{
[[self feedbackLabel] setText:@"Working ..."];
[[self doWorkButton] setEnabled:NO];
// async queue for bg work
// main queue for updating ui on main thread
dispatch_queue_t queue = dispatch_queue_create("com.sample", 0);
dispatch_queue_t main = dispatch_get_main_queue();
// do the long running work in bg async queue
// within that, call to update UI on main thread.
dispatch_async(queue,
^{
[self performLongRunningWork];
dispatch_async(main, ^{ [self workDone]; });
});
}
- (void)performLongRunningWork
{
// simulate 5 seconds of work
// I added a slider to the form - I can slide it back and forth during the 5 sec.
sleep(5);
}
- (void)workDone
{
[[self feedbackLabel] setText:@"Done ..."];
[[self doWorkButton] setEnabled:YES];
}
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