Multithreading in iOS (Multithreading in development)

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The application of multithreading in development

What is the main thread

A thread that starts by default after an iOS application runs, called the main thread or UI thread

Main thread action

• The page is displayed and refreshed
• Handle UI events, such as click events, scroll events, drag events, and so on

Note the main thread usage

• Do not put time-consuming operations in the main thread

• Time-consuming operations can jam the main thread and seriously affect fluency

  If put time-consuming operation in the main thread, when a user in 5 seconds, click on the button, the operation must be serialized because the thread, the click event will at this time in 10 seconds after lengthy operations, until 10 seconds after the time-consuming operation, click on the button to perform event, this can cause the UI to jam phenomenon, the following figure:

  

  If the time-consuming operation is placed in the child thread, the main thread and the child thread will do the time-consuming operation at the moment. When the user clicks the button at the fifth second, the child thread will do the time-consuming operation, and the main thread responds to the interface operation, so the UI will not be stuck. Therefore, the time-consuming operation should be placed in the background thread of the child thread, as shown in the figure:

  

Multithreaded implementation scheme