Continue to update and improve the answer - Recently, the Android friends around the blogger changed their pits and received interview invitations from major companies such as BAT, and came back to chat. The blogger recorded some useful interview questions that major companies must ask. I hope it will be helpful for your study, work, and interview. (The blogger will continue to collect and update these interview questions), the blogger will filter the interview questions for sharing and submission, thank you again for sharing the interview questions, friends and readers
Interview experience
1. I accidentally saw Zhihu's internal tweet and posted a resume. In the afternoon, my sister hr called me and arranged for the interview to be selected 3 days later. However, I had to test Ali again, so I didn't review it much.
- I got up at 8 o'clock and went to the Pioneer Park after 9 o'clock nervously. I feel that the atmosphere is very good. After waiting for a short time there, the uncle at the front desk will pour water for you.
one side:
He should be a research monk who has not been working for a long time. He came up with an algorithm question. The main test is to convert characters to int, and then analyzed the time complexity and space complexity. After that, I talked about the performance optimization of android listView and asked me about the characteristics and process of recycalView. Communication methods, I mainly talked about aidl and shared files, broadcasting, originally wanted to use java to install B, and I am still proficient in java, but the brother did not ask, he said wait a moment
Two sides:
The difficulty has increased obviously on the second side, and the interview tube should be the group leader. I prefer to listen to the structure. Just before I did a smart home project from the web backend, client, hardware, etc., I blew the logic on the hardware side. , Including bluetooth, wifi HTTP/IP protocol, transparent transmission, infrared and other sensors, and then web background I said I use sevlet, because the client itself mainly needs an interface, the database uses mysql, and did not ask rollback (hehe), and then put The client showed it to him. It was really ugly without art (this is not the point). Because there is a very important point in my project that wakes up the server to push in the background when the hardware is triggered. First, after the hardware is recognized, the serial port reads and writes data to The single-chip microcomputer writes the wifi buffer, the wifi transparently transmits data to my server through HTTP (TCP and IP can be used), the server obtains the mac logo, and pushes it to the TAG (family ID) or the user (Alias)
. Implementation principle.
1: Pull mode, http long connection or socket, just set the polling interval, shortcomings are poor timeliness
2: Push mode, good real-time performance, method 1, Google's own push platform (the network is too poor), method 2, xmpp Protocol (based on XML). In fact, the package is better. There is an open source package called asmark, which includes the push library XmppConnection. It is said that many companies use its own package library, but the open source demo only pushes, there is no delayed push, message temporary storage function, method 3. Using a three-way
algorithm: it is the problem of merging two ordered arrays, using two pointers to solve the problem O(n) each time, the algorithm pass
LruCache: install B first, and talk about what I wrote and the google V4 package What's the difference, mainly because there is no trimToSize method and no sizeof() to calculate the memory consumption size. I mainly rewrite LinkedHashMap and talk about the source code of LinkHashMap. In fact, I also read the source code analysis written by others. (Hey, after all, young Learn)
At last
For many junior and intermediate Android engineers, if they want to improve their skills, they often grow up by themselves. The unsystematic learning effect is inefficient, long and helpless. It’s normal to be discouraged after a long period of time, with huge time cost and effort, without seeing the desired effect.
Therefore, you must find the most suitable way for you to study, and have a way of thinking, otherwise you will not only waste time, but also delay future development together.
If you are stuck at the bottleneck of lack of learning resources, then just in time I can help you. The above knowledge notes are all free to share. If you need to get knowledge notes, you can click on my GitHub to get them for free.