Preface
I often hear people in the group have some negative attitudes towards Android, saying that Android is cold and want to change direction, but if you change the direction to become a big cow, then everyone can change it.
In fact, there is a "two-eight" law in any direction. There are always 20% of people who are very good. We must strive to become that 20%, so we must gradually increase our requirements, step out of the comfort zone, and try to break the game!
Now you can no longer stay skilled in the use of RxJava, Retrofit, OkHttp and various image libraries, but must master them thoroughly at the source code level. To be clear, no matter how awesome a library is, it is also an awesome author, so we must understand the principles as much as possible.
I would like to give you a few suggestions. First, you must endure loneliness and not be disturbed by the outside world; second, develop a long-term systematic learning plan and persevere; finally, pay attention to learning methods, not casual learning, many people only read books and blogs, but Never try to practice it, the understanding will certainly not be too deep, and it will be easy to forget after a long time.
If you want to take a high salary to achieve a qualitative leap in salary and technical improvement, the fastest way is for someone to take you to analyze the source code and framework together, so that learning is the most efficient, so here I share some source code and framework videos.
When chatting with a friend of mine in Alibaba a few days ago, I specifically asked the "hardcore" interviewer who developed Android for 10 years . What principles are asked in Alibaba's interviews . This article is hereby compiled, and I hope it will be helpful to everyone's interview.
BATJ big interview must ask Android principle questions
- HashMap principle
- The realization principle of ConcurrentHashMap
- HashTable implementation principle
- Do you understand the principles of broadcast transmission and reception? (Binder mechanism, AMS)
- Communication principle of traditional IPC mechanism (2 memory copies)
- The role and principle of the Binder mechanism?
- LRUCache principle
- Image loading principle
- Talk about AIDL? What is the principle?
- Talk about the principle of generics and give an example
- The principle of Handler
- The cause of memory leak caused by Handler and the best solution
- Why Looper's infinite loop will not cause the application to freeze
- The principle of AsyncTask
- The principle of ThreadLocal
- What is ANR? Under what circumstances will ANR occur? How to avoid it?
- Explain Context
- The method of thread creation in java, the working principle of thread pool
- Thread synchronization mechanism and principle, with examples
- Memory recovery mechanism and GC algorithm; GC principle and timing and GC objects
- Principles of Hot Repair
- Analysis of plug-in principle
- Constitutional principle
- ARouter routing principle:
- Distinguish the usage of Animation and Animator, and outline the principle
- Which network load libraries have you used? The realization principle of OkHttp and Retrofit?
- The principle of volatile
- synchronized principle
- The realization principle of tweening animation
- MVC MVP MVVM principle and difference
Algorithmic questions must be asked in interviews
1. What are the sorting algorithms?
2. Which is the fastest sorting algorithm?
3. Handwritten a bubble sort
4. Handwritten quick sort code
5. Quick sort process, time complexity, space complexity
6. Handwritten heap sort
7. Heap sort process, time complexity and space complexity
8. Write you Known sorting algorithm, time and space complexity, stability
9. Binary tree gives the root node and target node, and finds the path from the root node to the target node.
10 Which algorithm should I choose to sort by age for more than 20,000 Alibaba employees?
11. GC algorithm (advantages and disadvantages of various algorithms and application scenarios)
12. Ant colony algorithm and Monte Carlo algorithm
13. Substring inclusion problem (KMP algorithm) write code to achieve
14 an unordered, non-repeated array, output N Element, so that the sum of N elements is added to M, giving time complexity and
space complexity. Handwriting algorithm
15. Trillion-level two URL files A and B, how to find the difference C of A and B (hint: Bit mapping -> hash grouping ->
multi-file read and write efficiency -> disk addressing and application level Optimization of addressing)
16. How to try to find the nearest merchant function in Baidu POI (hint: coordinate mirroring + R tree).
17. Find common elements in two non-repeating array collections.
18. In two non-repeating array collections, both of which are massive amounts of data and cannot fit in the memory. How to find common
elements?
19. There are 1 million integers in a file, separated by spaces. In the program, it is judged whether the integer entered by the user is in this file
. Speak the best way
20. The memory occupied by a Bitmap and the calculation of the memory occupation
End of sentence
When you plan to quit, you should put "what can I learn after a successful job hopping? What are the benefits for my future development" in the first place. These things are the key to truly guide you. Try to "make the best use of everything" before hopping, and do your job well. It is best to complete a project or get promoted before leaving. Job-hopping is not an end, but a means to achieve the ultimate professional goal
Finally, I wish you a job promotion and salary increase, and an interview to get your favorite offer.
For this reason, I have compiled some information about mobile developers’ needs at the end of the article. Welcome everyone to receive the method for free
: click on my GitHub
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