background
Netizens often ask two questions in Zhihu Q&A: "Is there any prospect for learning mobile development now?" "What else can be studied in development?". Netizens replied: "I still learn mobile development now? Just like joining the national army in 49!" In fact, these two questions correspond to the same phenomenon, whether it is preparing to enter the industry or just entering the industry, or a more senior developer, for the future of the mobile development career , There are some confusion, some anxiety. Why is this happening?
In recent years, with breakthroughs in core algorithms represented by deep learning, the improvement of computer computing capabilities, and the development of mobile internet and cloud computing technologies, the development of AI technology has begun to affect people's lives. At this stage, artificial intelligence technology has been used in many fields such as smart security, smart transportation, financial service industry, medical industry, industry, and mobile Internet, and has triggered a major change in various industries.
Two years ago, many entrepreneurs discussed how to adapt to the mobile Internet in Wuzhen, but today the era of mobile Internet is over. Relevant data forecasts show that the growth rate of mobile Internet users in China in 2017 will be around 3.5%, and in 2018 it will drop to less than 3% . In 2013, this figure was nearly 15%, and the growth brought about by the demographic dividend of the mobile Internet has peaked.
So the end here is not to say that you don’t need mobile phones to access the Internet, but that the mobile Internet market has entered a relatively stable stage . The Internet population penetration rate exceeds 50%, and there is no possibility of unicorns in this outlet.
【one side】
- What are the four major components of Android? Which one are you most familiar with?
- Activity life cycle?
- What happens when I rotate the screen?
- Java constant pool? Are the references equal to different String assignment methods?
- The realization of HashMap? Treeing threshold? Load factor? Growth factor?
Handwritten code: O(1) singly linked list element deletion (×: Unlucky kid has never seen this routine... After being prompted, I didn’t think of it, which shows the importance of doing the question)
Handwritten code: get the last N elements of the singly linked list
【Two Sides】
- Have you written C++?
- Do you know the allocator of STL container?
- Handwritten code: realize lock-free synchronization (×: I wrote the CAS operation and was interrupted, saying that the specific ARM processor does not have this synchronization primitive and cannot rely on related instructions. It also does not include semaphores.)
- Handwritten code: Customize the scene and implement a memory pool that meets the needs (×: I wrote a few bugs dizzy, the interviewer’s eyes... and I feel that the recycling algorithm is not good enough, thank you for letting it go)
- Handwritten code: find the top K numbers from the long sequence, and sort by heap
- Do you understand the garbage collection algorithm of JVM?
- Object reachability analysis, which is the GC root?
- The fundamental difference between TCP and UDP?
- In what scenarios is UDP used? why?
- Ask your resume about FFmpeg
- My question:
- Which group does the interviewer belong to?
Is ByteDance really short of people this year? What is the recruitment strategy? (Answer: Yes. It doesn’t matter if the project and the internship experience suffer. This year’s recruitment focuses on the basics. I will definitely not give you last year.)
【Three sides】
- Introduce the project, the app made during the summer vacation of high school
- Draw the module diagram of a certain function and write the related interface
- What's wrong with this design? How to improve?
- What protocol does QQ video chat use?
- Why does the video chat freeze?
- The details of the TCP flow control algorithm? (×: The functional relationship of the packet rate growth is not clear, thank the interviewer for letting it go)
- Assuming that a node has its own packet loss rate, how to determine whether the packet loss is caused by insufficient bandwidth or random packet loss?
- If the video chat is stuck, how to alleviate it at the application level?
- Handwritten code: addition of large integers, code readability is required (×: I wrote a series of funny bugs again, I was fooled by the two sides)
- What causes the lag in the Android application?
- What is the difference between Service and Thread? On which thread does the service code run?
- AsyncTask？Executor？
- What are the disadvantages of AsyncTask?
- Have you used IntentService? (×: Never used it, it feels like a convenient facility suitable for single calculation tasks)
My question:
- What does the interviewer do?
- What is the interviewer's opinion of non-major students?
- What shortcomings does the interviewer think of me?
At last
It is said that three years is a hurdle for programmers, whether they can be promoted or improve their core competitiveness, these few years are very critical.
With the rapid development of technology, from which aspects can we learn to reach the level of a senior engineer and finally advance to an Android architect/technical expert? I have summarized these 5 big pieces;
I have collected and sorted out the interview questions of Alibaba, Tencent, ByteDance, Huawei, Xiaomi and other companies in the past few years, and sorted out the requirements and technical points of the interview into a large and comprehensive "Android Architect" interview Xmind (in fact, it is better than Expect to spend a lot of effort), including knowledge context + branch details.
" Android Architecture Video + BAT Interview Special PDF + Study Notes "
There are a lot of materials for learning Android on the Internet, but if the knowledge learned is not structured, and when you encounter problems, you just taste it and don’t study it in depth, then it is difficult to achieve real technological improvement. I hope ** this systematic technical system ** can provide you with a reference for your direction.
A6%82%E4%BD%95%E9%9D%A2%E8%AF%95%E6%8B%BF%E9%AB%98%E8%96%AA%EF%BC%81.md)** Have a direction reference for everyone.
Although the road will be bumpy in 2021, everyone is saying that Android is going to decline, but don't panic, make your own plans, learn your own habits, competition is everywhere, and every industry is like this. Believe in yourself, there is nothing impossible, only unexpected. I wish you all the best in 2021.