Synchronous: execute in code order, not asynchronously after the preceding execution: Not in accordance with the order code execution, the execution more efficient implementation of asynchronous principle is the main line of Cheng Pa a child thread out to perform a task, the child thread of execution will not affect the main thread of execution, so the child thread is usually used to complete some execution for a long time that could be the user perceived or serious will block the main thread of the task. Callback function: Child thread is completely separate from the main thread, so when the main thread sent some tasks to the main thread after the child thread lost with the main thread synchronization, the main thread can’t determine the end of the child thread, if after the child thread to deal with some things can’t be merged into the main thread, and then through the callback function to solve this problem, Tells the child thread what to do when it finishes the task.
Recent interview pieces of abuse the front end of the small white one, countless times to give up, but my mind has failed to achieve a voice told myself to give up the study to other industry knowledge will encounter bottlenecks, do not want to be a face difficult give up turned to find a new way, only have grasped the nettle or it has been on the way to give up is a waste of time.
Although the interview made me very uncomfortable, but it did expose two obvious problems: first, can only practice but many principles can not be explained, and second, they can not clearly express what they know in language. So write down some notes to help you understand and organize the interview language