iOS crash handling: This application was modifying the AutoLayout engine from a background thread

First, error hints

Today at the time of development encountered a crash problem, "This application is modifying the AutoLayout engine from a background thread, which can leads to engine C  Orruption and weird crashes. This would cause an exception in a future release. "

Second, the wrong wording

Let's take a look at the code's wording:

Iii. Causes of Errors

Later, after observing the code, it was discovered that the UI-caused crash was updated in the child thread. When we learn multithreading, we will certainly see a sentence: The UI must be updated in the main thread. This is the main cause of the crash, write code GCD related code must remember to update the UI operation must be placed in the main thread operation.

Iv. Methods of Solution

Now that you know to update the UI on the main thread, just add the code to the original code:

iOS crash handling: This application was modifying the AutoLayout engine from a background thread