2019 iOS whole network interview questions and answers summarize!

A, Runtime

• What isa objc of a pointer to an object? what's the effect?
• How much memory space occupied by the object a NSObject?
• Talk about understanding class_rw_t of?
• Talk about understanding class_ro_t of?
• Talk about understanding isa pointer
• Runtime way to talk about caching? In the form of storage, data structures, and the search process?
• Use runtime Associate associated method object, you need to release in dealloc when the main subject of it?
• Data structure instance of an object?
• What is the method swizzling (commonly known as black magic)
• When will the reported abnormal unrecognized selector?
• How to add properties to Category? Associated objects are stored in what form?
• You can increase the instance variables to get the compiled class? Can you add an instance variable to the class created in runtime? why?
• Data structure class object?
• How to find the corresponding runtime IMP address selector?
• How runtime automatically set to nil weak variables? You SideTable know it?
• What objc in sending a message to a nil object is going to happen?
• objc when sending a message to an object, what happened?
• isKindOfClass and isMemberOfClass
• Category After compiling, what is the time to merge with the original class together?
• Category What are the uses?
• Category realization of the principle?
• _objc_msgForward function is doing what
• [self class] 与 [super class]
• Code a problem
• Code title two

Two, Runloop

• Why NSTimer sometimes so bad?
• AFNetworking how to use Runloop?
• autoreleasePool is released when?
• PerformSelector implementation principle?
• PerformSelector: afterDelay: whether this method works in the sub-thread? why? How to deal with it?
• RunLoop of Mode
• RunLoop implementation mechanism
• RunLoop and thread
• RunLoop data structure
• RunLoop concept
• RunLoop and NSTimer
• Talk about the Observer?
• Explain NSTimer
• Explain 事件响应the process?
• Explain the process of gesture recognition?
• What is asynchronous rendering?
• Runloop explain the process of using the page rendering?

Three, Objective_C language features

• KVC(Key-value coding)
• KVO (Key-value observing)
• Classification, extension, agent (Delegate)
• Keyword property
• Notification (NSNotification)

Four, Animation

• Tell me about the understanding of the CALayer.
• CALayerThe Contentsfew under several key attributes:

Five, Block

• Several forms of Block
• Block variables intercepted
• What is Block?

Six, UI-related

Seven, multithreading

• Processes, Threads
• Multi-process, multi-threaded
• Task queue
• iOS multithreading
• GCD --- queue
• Deadlock
• GCD task execution order
• dispatch_barrier_async
• dispatch_group_async
• Dispatch Semaphore
• Delay function (dispatch_after)
• Implemented using a single embodiment dispatch_once
• NSOperationQueue advantage
• NSOperation and NSOperationQueue
• NSThread + runloop achieve permanent thread
• Spin and mutex lock

Eight, memory management

• In Obj-C, how to detect memory leaks? You know which way?
• How to override the property at MRC Setter and Getter_
• Circular references
• Word on what 悬垂指针? What is 野指针?
• Talk about understanding retain, copy, assign, weak, _Unsafe_Unretain keyword
• Whether or not understand the concept of deep copy and shallow copy, how deep copy collections
• Use automatic reference counting principles to be followed
• Can you briefly Dealloc implementation mechanism
• What memory region 5, respectively?
• What memory management default keyword is?
• Memory management scheme
• Memory layout
• Talk about iOSunderstanding memory management
• Talk about @dynamickeywords?
• A brief talk about @autoreleasePooldata structures?
• Access __weakmodified variables, has already been registered in the @autoreleasePoolmiddle? why?
• retain, releaseImplementation mechanism?
• The MRC (manual reference count) and ARC (automatic reference counting)
• BAD_ACCESS Under what happens?
• autoReleasePool When was it released?
• ARC principle of automatic memory management
• ARC What had been done at runtime?
• ARC What had been done at compile time
• ARCOf retainCounthow the stored?
• __weakProperty modified variables, how strong references in the variables are not set to automatic nil?
• __weakAnd _Unsafe_Unretainthe difference?

Nine, design patterns

• How to design a statistical framework for long time?
• How to design a picture frame buffer?
• Six design principles of programming?

Ten, data security and encryption

• RSA asymmetric encryption
• Brief SSLencryption process by which encryption method, so why do?

Eleven, Data Structures and Algorithms

• iOS development data structure
• iOS algorithm interview questions (a)
• iOS algorithm interview questions (b)

Twelve, network-related

• HTTP protocol
• The HTTPS, symmetric encryption, asymmetric encryption
• Based on a simple chat Demo UDP's
• Characteristics of UDP, UDP packets and error detection structure
• TCP, three-way handshake, the fourth wave, code implementation

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