NSProgressIndicator进展与For循环? [英] NSProgressIndicator progress with For loops?
问题描述
我的应用程序通过一堆For循环做了很多工作.它计算了大量的字符串,并且可能需要一整分钟才能完成.
My application does a lot of work with a bunch of For loops. It calculates a massive amount of strings, and it can take over a whole minute to finish.
所以我在应用程序中放置了一个NSProgressIndicator.
So I placed a NSProgressIndicator in my app.
在循环中,我使用了NSProgressIndicator的"incrementBy"功能.但是,我看不到实际的条形填充.
Within the loops, I used the "incrementBy" function of the NSProgressIndicator. However, I don't see the actual bar filling up.
我怀疑这是因为循环可能会消耗所有能量,因此NSProgressIndicator不会(以图形方式)更新.
I suspect that's because of the loops taking all power possible, and thus the NSProgressIndicator is not updated (graphically).
那我该如何进步?
推荐答案
您的for
循环是否在主线程或后台线程上运行?如果它们在主线程上运行,则GUI将永远没有机会更新自身以反映进度变化,因为这只会在runloop的末尾(即,函数完成运行之后)发生.
Are your for
loops running on the main thread or in a background thread? If they're running on the main thread, the GUI will never get a chance to update itself to reflect the progress change as this will only happen at the end of the runloop, i.e. after your functions have finished running.
如果您的for
循环在后台运行,则您很顽皮!除了主线程外,您不应该从任何地方更新GUI.如果您的目标是现代系统,则可以使用GCD轻松解决此问题.
If your for
loops are running in the background, you're being naughty! You shouldn't update the GUI from anywhere but the main thread. If you're targeting a modern system, you can use GCD to trivially work around this.
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^(void) {
for (int i = 0; i < n; i++) {
// do stuff
dispatch_async(dispatch_get_main_queue(), ^(void) {
// do your ui update here
});
}
});
或者,您可以重写for
循环以进一步利用GCD并使用dispatch_apply
.上面的等价于:
Alternatively, you can rewrite your for
loops to take advantage of GCD even further and use dispatch_apply
. The equivalent of the above would be:
dispatch_apply(n, DISPATCH_QUEUE_PRIORITY_DEFAULT, ^(size_t i) {
// for loop stuff here
dispatch_async(dispatch_get_main_queue(), ^(void) {
// do your ui update here
});
});
请注意,使用 dispatch_apply
表示循环的每个迭代"都可以相对于彼此并发运行,因此,如果您的for
循环需要以串行方式运行,则该循环将不适用
Note that using dispatch_apply
means that each "iteration" of the loop may run concurrently with respect to one another, so this won't be applicable if your for
loop requires to be run in a serial fashion.
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