Android Face Test summary

1. Android DVM processes and Linux processes, whether the application process is the same concept

DVM refers to DALIVK virtual machines. Each Android application runs in its own process and has a separate instance of the Dalvik virtual machine. And each DVM is a process in Linux, so it can be thought of as the same concept.

What is the role of the EF file for 2.sim cards

SIM card file system has its own specifications, mainly in order to communicate with the mobile phone, SIM itself can have its own operating system, EF is for storage and communication with the mobile
What kinds of embedded operating system memory management are there, and what are the characteristics?
page, segment, section page, using the MMU, virtual space and other technologies

3. What is embedded real-time operating system and is the Android operating system part of the RTOs?

Embedded real-time operating system refers to when the external events or data generated, can be accepted and fast enough to be processed, the results of the processing can be within the specified time to control the production process or to respond quickly to the processing system, and control all real-time tasks coordinated operation of the embedded operating system. Mainly used in industrial control, military equipment, aerospace and other areas of the system response time has stringent requirements, which requires the use of real-time systems. Can be divided into soft real-time and hard real-time two kinds, and Android is based on the Linux kernel, and therefore belongs to soft real-time.

4. What is the maximum number of bytes in a text message?

Chinese 70 (including punctuation), English 160 bytes
What are the types of animations in Android, and what are their characteristics and differences?
Two kinds, one is tween animation, and another is frame animation. Tween animations, which enable the view component to move, zoom in, zoom out, and create transparency, another frame animation, a traditional animation method, is implemented by sequential playback of a well-arranged picture, similar to a movie.

Principles of the 5.handler mechanism

Andriod provides Handler and Looper to meet the communication between threads. Handler first-out principle. The Looper class is used to manage the exchange of messages (message exchange) between objects within a particular thread.
1) Looper: A thread can produce a Looper object that manages this line thread message queue.
2) Handler: You can construct a Handler object to communicate with Looper in order to push a new message into the message queue, or to receive a message sent by Looper out of the message queue.
3) Message queue (Message Queuing): Used to hold messages placed by the thread.
4) Thread: The UI thread is usually the main thread, and the Android launcher will create a message Queue for it.
MVC (Model_view_contraller) "Model View controller". MVC applications are always made up of these three parts. Event causes the controller to change the model or view, or to change both. As long as the controller changes the data or attributes of the models, all dependent view will be updated automatically. Similarly, as long as the controller changes the View,view will
Get the data from the potential model to refresh yourself.
View redraw and memory leaks seem to be a frequently asked question in the interview.

Android Face Test summary