如何从iOS中的非UI线程更新UI标签 [英] How to update a UI label from a non UI thread in iOS

问题描述

我是iOS开发的新手，我有简单的目标-c类MoneyTimer.m用于运行计时器，从那里我想用更改的计时器值更新UI标签。
我想知道如何从非UI线程访问UI元素？我正在使用Xcode 4.2和故事板。

I am new to iOS development, I have plain objective -c class "MoneyTimer.m" for running timer, from there i want to update the an UI label with the changing value of timer. I want to Know how to access the UI element from non UI thread ? I am Using Xcode 4.2 and storyboarding.

在blackberry中，只需获取事件锁即可从非UI线程更新UI。

In blackberry simply by getting the event lock one can update the UI's from non UI thread.

//this the code from MyTimerClass

 {...
    if(nsTimerUp == nil){

        nsTimerUp = [NSTimer scheduledTimerWithTimeInterval: 1.0 target:self selector:@selector(countUpH) userInfo:nil repeats: YES];
 ...}

(void) countUpH {

sumUp = sumUp + rateInSecH;
 **//from here i want to update the UI label **
...
}

推荐答案

这是最快捷，最简单的方法：

This is the quickest and simplest way to do it is:

- (void) countUpH{

   sumUp = sumUp + rateInSecH;
   //Accessing UI Thread
   [[NSOperationQueue mainQueue] addOperationWithBlock:^{

      //Do any updates to your label here
      yourLabel.text = newText;

   }];
}

如果你这样做，你不必切换到另一个方法。

If you do it this way you don't have to switch to a different method.

希望这会有所帮助。

Sam

这篇关于如何从iOS中的非UI线程更新UI标签的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！