Prepare for the 1000 Android interview questions and answers that golden nine silver ten must ask in 2022, and completely solve the interview problems

Preface

Both school recruitment and social recruitment can not avoid all kinds of interviews , How to prepare for the interview is particularly important .

This is not the golden nine silver ten , I believe there are many small partners preparing for social recruitment or job hopping , Recently, Xiaobian also often brushes the interview questions , Found a lot on the Internet Android There are no answers to the interview questions , So it took a long time to collect and sort out this set of Android Interview questions , I hope it can help you ~

The blogger has organized the following interview questions into one Android Interview manual , yes PDF Version of . It covers ：ava part 、 Four components 、UI、 Asynchronous mechanism 、 Message mechanism 、 performance optimization 、IPC、SDK、 Integrated technology 、 data structure 、 Design patterns 、 computer network 、Koltin Etc. technology stack .

The following interview questions ,VX Scan the code for free .

Chapter one Java aspect

（ One ）Java Base part

• The difference between abstract class and interface ？
• Let's talk about final,static,synchronized What can keywords modify , And the effect of modification ？
• Please give us a brief introduction String、StringBuffer and StringBuilder The difference between ？
• “equals” And “==”、“hashCode” The differences and use scenarios ？
• Java The difference between deep copy and light copy ？
• Talk about Error and Exception The difference between ？
• What is the reflection mechanism ？ What are the application scenarios of reflection mechanism ？
• Talk about how to rewrite equals() Method ？ Why rewrite hashCode()？
• Java in IO There are several kinds of streams ?BIO,NIO,AIO What's the difference? ?
• Talk to you about Java Understanding of type erasure in generics , And talk about its limitations ？
• String Why is it designed to be immutable ？
• Tell me about your right Java The understanding of annotation ？
• To talk about Java Member variables , Creation and recycling of local and static variables ？
• Please talk about Java in String.length() How it works ？
• 

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（ Two ）Java aggregate

• Talk about List,Set,Map The difference between ？
• Talk about ArrayList and LinkedList The difference between ？
• Please say HashMap And HashTable The difference between
• To talk about ArrayList Capacity expansion mechanism of ？
• HashMap Implementation principle of ？
• Please briefly LinkedHashMap How it works and how it is used ？
• Let's talk about it ConcurrentHashMap The understanding of the ?

（ 3、 ... and ）Java Multithreading

• Java What are the ways to use multithreading in ？
• Let's talk about several states of threads ？
• How to realize synchronization in multithreading ？
• Talk about thread deadlock , How to effectively avoid thread deadlock ？
• Talk about the causes of thread blocking ？
• Please talk Thread in run() And start() The difference between ？
• synchronized and volatile The difference between keywords ？
• How to ensure thread safety ？
• Talk about ThreadLocal Usage and principle ？
• Java In the thread notify and notifyAll What's the difference? ？
• What is a thread pool ？ How to create a thread pool ？
• To talk about java Several common locks of threads ？
• Talk about threads sleep() and wait() The difference between ？
• What is the pessimistic lock and the optimistic lock ？
• What is? BlockingQueue？ Please analyze its internal principle and talk about its use scenario ？
• To talk about java What are thread safe collections ？
• Java Why do you see Atomic class ？ Try to analyze its principle and disadvantages ？
• say something ThreadLocal Usage scenarios of ？ And Synchronized What are the characteristics of comparison ？

（ Four ）Java virtual machine

• To talk about JAVA Garbage collection mechanism ？
• Answer what is strong 、 soft 、 weak 、 Virtual references and the differences between them ？
• sketch JVM Loading mechanism and loading process of classes in ？
• JVM、Dalvik、ART The principle and difference of the three ？
• Please talk Java Memory recovery mechanism ？
• JMM What is it? ？ What problems does it have ？ How to solve ？
  

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Chapter two Android aspect

（ One ）Android The four components are related

• Activity And Fragment Several common ways of communication between ？
• LaunchMode Application scenarios of ？
• BroadcastReceiver And LocalBroadcastReceiver What's the difference? ？
• about Context, How much do you know ?
• IntentFilter What is it? ？ What are the usage scenarios ？
• To talk about startService and bindService The difference between , Life cycle and usage scenarios ？
• Service How to keep alive ？
• A brief introduction ContentProvider How to realize data sharing ？
• When switching between horizontal and vertical screens Activity Life cycle of ?
• Activity in onNewIntent Method invocation timing and usage scenario ？
• Intent Is there a limit on the size of the transmitted data ？ How to solve ？
• say something ContentProvider、ContentResolver、ContentObserver The relationship between ？
• say something Activity Loading process ？

（ Two ）Android Asynchronous task and message mechanism

• HandlerThread Usage scenarios and usage ？
• IntentService Application scenarios and use gestures ？
• AsyncTask Advantages and disadvantages of ？
• Talk to you about Activity.runOnUiThread The understanding of the ？
• Whether the child thread can update UI？ Why? ？
• Talk about Handler Mechanism and principle ？
• Why create in child thread Handler Would throw exceptions ？
• Try to analyze from the perspective of source code Handler Of post and sendMessage Differences of methods and application scenarios ？
• Handler There is Loop Dead cycle , Why not block the main thread , What is the principle ?
  

（ 3、 ... and ）Android UI Rendering correlation

• Android Make up the difference between animation and attribute animation ？
• Window and DecorView What is it? ?DecorView How to communicate with Window To make a connection ?
• Briefly Android in UI Refresh mechanism of ？
• LinearLayout, FrameLayout, RelativeLayout Which is more efficient , Why? ？
• Talk about Android Event distribution mechanism of ？
• Talk about customization View The process of ？
• in the light of RecyclerView What optimizations have you made ？
• Talk about how to optimize ListView？
• Talk about customization LayoutManager The process of ？
• What is? RemoteViews？ What are the use scenarios ？
• Talk about getting View Several methods of width and height ？
• Talk about interpolator and estimator ？
• getDimension、getDimensionPixelOffset and getDimensionPixelSize Differences among the three ？
• Please talk about... In the source code StaticLayout Usage and application scenarios ？
• used ConstraintLayout Do you ？ What are its characteristics ？
• About LayoutInflater, How it passes inflate Method to get the specific View Of ？
• To talk about Fragment Lazy loading ？
• Talk about RecyclerView Cache mechanism ？
• Please talk View.inflate and LayoutInflater.inflate The difference between ？
• Please talk invalidate() and postInvalidate() Differences of methods and application scenarios ？
• Talk about customization View And customization ViewGroup？
• To talk about SurfaceView And TextureView Usage scenarios and usage ？
• To talk about RecyclerView.Adapter How are the refresh methods different ？
• Talk to you about Window and WindowManager The understanding of the ？
• To talk about Activity,View,Window The relationship among the three ？
• I know WindowInsets Do you ？ What applications does it have ？
• Android in View Differences between several common displacement modes ？
• Why? ViewPager nesting ViewPager, Inside ViewPager Scrolling is not blocked ？
• Please talk Fragment Life cycle of ？
• Please talk about what is synchronization barrier ？
• To talk about ViewDragHelper How it works ？
• Talk about the screen refresh mechanism ？

（ Four ）Android Performance tuning related

• Talk to you about Android Understanding of performance optimization ？
• Under what circumstances can memory leakage be caused ？
• Customize Handler How to effectively avoid memory leakage when ？
• What circumstances can lead to oom problem ？
• ANR Scenarios and solutions ？
• Talk about Android Memory optimization in ？
• Talk about the skills of layout optimization ？
• Android Picture optimization scheme in ？
• Android Native Crash How to analyze and locate the problem ？
• Talk about how to give apk Slimming ？
• Talk about how you optimize App Of the startup process ？
• Talk about the steps of code obfuscation ？
• Talk about how to WebView To optimize ？
• How to handle the loading of large drawings ？
• Talk about how to optimize network requests ？
• Please talk about how to load Bitmap And prevent memory overflow ？
  ​ Bold style

（ 5、 ... and ）Android Medium IPC

• Please answer Android Communication between processes ？
• Please tell me about you Binder The understanding of mechanism ？
• Talk about AIDL？

（ 6、 ... and ）Android System SDK relevant

• Please talk briefly about Android The architecture of the system ？
• SharedPreferences Is it thread safe ？ its commit and apply What's the difference ？
• Serializable and Parcelable The difference between ?
• Please give us a brief introduction Android 7.0 New features ？
• Talk about ArrayMap and HashMap The difference between ？
• In a nutshell LruCache Principle ？
• Why recommend SparseArray Instead of HashMap？
• PathClassLoader and DexClassLoader What's the difference ？
• say something HttpClient And HttpUrlConnection The difference between ？ And talk about why the former was replaced ？
• What is? Lifecycle？ Please analyze its internal principle and usage scenario ？
• To talk about Android Signature mechanism of ？
• Talk about Android apk Build process ？
• Briefly Android 8.0、9.0 What new features have been added ？
• Talk about Android10 What has been updated ? How to adapt ?
• Please briefly Apk Installation process ？
• Java And JS How code is muted ？ Have you done relevant optimization ？
• What is? JNI？ Let's talk about how to realize Java And C++ Intermodulation of ？
• Please briefly start by clicking the icon app Startup process ？
  （ 7、 ... and ） Third party framework analysis
• To talk about LeakCanray How it works ？
• To talk about EventBus Principle ？
• Talk about interceptors in network requests （Interceptor）？
• To talk about Glide Cache mechanism ？
• ViewModel What problems do you want to solve ？ And briefly talk about its internal principle ？
• Please talk about the dependency injection framework ButterKnife Implementation principle of ？
• To talk about RxJava Back pressure principle ？
  

（ 8、 ... and ） Integrated technology

• Please tell me about you MVC and MVP The understanding of the ？
• Introduce what you know Android Several storage methods ？
• Briefly describe the principle of thermal repair ？
• Talk about how to adapt to more models ？
• Please talk about how you carry out multi-channel packaging ？
• MVP How do you deal with Presenter Layer to prevent memory leakage ？
• How to calculate the memory space occupied by a picture ？
• Have you met 64k problem , How to solve ？
• How to optimize Gradle The speed of building ？
• How to get Android Unique equipment ID？
• To talk about Android P Ban http What's the impact on our development ？
• What is? AOP？ stay Android What application scenarios does it have in ？
• What is? MVVM？ How do you apply it to specific projects ？ – Please talk about how you realize data embedding ？
• If you realize the breakpoint upload function , What do you think should be done ？
• webp and svg What are the characteristics of the pictures in different formats ？ How to be in Android Use in ？
• Tell me how you do unit testing ？ And how to apply it to MVP and MVVM in ？
• about GIF What are the ideas and suggestions for image loading ？
• Why migrate the project to AndroidX？ How to migrate ？

（ Nine ） Data structure

• What is bubble sorting ？ How to optimize ？
• Please use Java Implement a simple single linked list ？
• How to reverse a single linked list ？
• Talk about your understanding of time complexity and space complexity ？
• Talk about how to judge a linked list into a ring ？
• What is a red-black tree ？ Why red black trees ？
• What is a quick sort ？ How to optimize ？
• Talk about circular queues ？
• How to judge the cross of single linked list
  ​

（ Ten ） Design patterns

• Please briefly talk about singleton mode ？
• How much do you know about the six basic principles of object orientation ？
• Please list several common factory patterns and explain their usage ？
• Talk about the design patterns and usage scenarios used in the project ？
• What is agent mode ？ How to use ？Android Proxy mode in the source code ？
• Let's talk about singleton mode , Builder pattern , Usage scenario of factory mode ？ How to choose ？
• Talk about your understanding of prototype patterns ？
• Please talk about the principle of strategy mode and its application scenario ？
• The difference between static agent and dynamic agent , What scenarios to use ？
• Let's talk about the usage scenario of the responsibility chain model ？

（ 11、 ... and ） Computer network

• Please briefly Http And Https The difference between ？
• say https,udp,socket difference ？
• Please briefly describe http Process of network request ？
• To talk about TCP/IP Three handshakes , Four waves ？
• Why do you say Http It is a reliable data transmission protocol ？
• TCP/IP What are the layers of the agreement ？TCP and HTTP Which floor do they belong to ？

（ Twelve ）Kotlin aspect

• Please briefly describe what is Kotlin？ What are its characteristics ？
• Kotlin Notes in @JvmOverloads The role of ？
• Kotlin in List And MutableList The difference between ？
• Kotlin Several common ways to implement singleton in ？
• Talk to you about Kotlin Medium data Keyword understanding ？ What are the characteristics compared with ordinary classes ？
• What are delegate properties ？ Please briefly talk about its usage scenario and principle ？
• Please give an example of Kotlin in with And apply Application scenarios and differences of functions ？
• Kotlin in Unit The role of type and its relationship with Java in Void The difference between ？
• Kotlin in infix The principle and usage scenario of keywords ？
• Kotlin What are the visibility modifiers in ？ Compared with Java What's the difference? ？
• You feel Kotlin And Java What problems should be paid attention to in hybrid development ？
• stay Kotlin in , What is deconstruction ？ How to use ？
• stay Kotlin in , What is an inline function ？ What's the role ？
• Talk about kotlin Construction method in ？ What are the precautions ？
• Talk about Kotlin Medium Sequence, Why does it handle collection operations more efficiently ？
• Please talk Kotlin Medium Coroutines, What's the difference between it and thread ？ What are the advantages ？
• Kotlin How to safely handle nullable types ？
• say something Kotlin Medium Any And Java Medium Object What are the similarities and differences? ？
• Kotlin Does the data type in have implicit conversion ？ Why? ？
• Kotlin There are several ways to traverse the collection in ？
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PS: We should remember that the purpose of the interview questions is not to let everyone recite the questions , But to help you review from different dimensions , Learn from others' strong points and close the gap . Those who need the above interview questions can click on the card below to scan the code for free .