Interview Questions.

Top 100+ Android Interview Questions And Answers

fluid

Top 100+ Android Interview Questions And Answers

Question 1. What Is Android?

Answer :

Android is a stack of software for cell gadgets which has Operating System, middleware and some key packages. The application executes within its very own manner and its personal instance of Dalvik Virtual Machine. Many Virtual Machines run successfully via a DVM device. DVM executes Java languages byte code which later transforms into .Dex format files.

Question 2. Explain About The Exceptions Of Android?

Answer :

The following are the exceptions which can be supported via Android
* InflateException : When an mistakes situations are befell, this exception is thrown
* Surface.OutOfResourceException: When a floor is not created or resized, this exception is thrown
* SurfaceHolder.BadSurfaceTypeException: This exception is thrown from the lockCanvas() method, while invoked on a Surface whose is SURFACE_TYPE_PUSH_BUFFERS
* WindowManager.BadTokenException: This exception is thrown at the time of seeking to upload view an invalid WindowManager.LayoutParamstoken.

Core Java Interview Questions
Question 3. Why To Use Android?

Answer :

Android is beneficial due to the fact:
*It is simple and powerful SDK
*Licensing, Distribution or Development fee isn't always required
*Easy to Import 0.33 birthday celebration Java library
*Supporting systems are ? Linux, Mac Os, Windows

Question 4. Describe Android Application Architecture?

Answer :

Android Application Architecture has the following additives:
* Services - like Network Operation
* Intent - To perform inter-communication among sports or services
* Resource Externalization - consisting of strings and snap shots
* Notification signaling customers - light, sound, icon, notification, conversation and so on.
* Content Providers - They share facts among applications

Core Java Tutorial
Question five. What Are The Features Of Android?

Answer :

*Components may be reused and replaced through the application framework.
*Optimized DVM for cell gadgets
*SQLite allows to shop the records in a established way.
*Supports GSM phone and Bluetooth, WiFi, 3G and EDGE technology
*The development is a mixture of a tool emulator, debugging gear, reminiscence profiling and plug-in for Eclipse IDE.

BLACKBERRY Interview Questions
Question 6. Are The Android Releases Available In A Rom?

Answer :

No, Android isn't always yet to be had in a ROM format. Currently Android is installed by way of the usage of a clean SD Card, and booted from there. It is booted through walking a special utility called 'Haret.Exe' dwelling for your SD Card in order to terminate the Windows kernel and boot into Linux/Android. It cannot without difficulty be run from ROM because a) it is too experimental to threat installing ROM and then killing a device and b) WinMo does some hardware initialisation that isn't always documented, however is wanted earlier than Android can run.

Question 7. Can You Play Android 2.1 Games On Android 2.2?

Answer :

no.As i have a 2.2 android telephone, its very hard to discover video games for it. The 2.2 android will not be capable of assist that sort of recreation.

BLACKBERRY Tutorial IOS Interview Questions
Question 8. What Is Android Runtime?

Answer :

Android includes a fixed of center libraries that offers maximum of the capability available inside the corelibraries of the Java programming language. Every Android software runs in its personal process, with its personal instance of the Dalvik virtual machine. Dalvik has been written so that a tool can run multiple VMs effectively. The Dalvik VM executes documents in the Dalvik Executable (.Dex) format that's optimized for minimum reminiscence footprint. The VM is register-primarily based, and runs classes compiled by a Java language compiler that have been converted into the .Dex format by the protected ?Dx? Tool.

Question nine. Creating An Android Application Using The Eclipse Plugin?

Answer :

Using the Android Eclipse plugin is the fastest and easiest manner to begin developing a brand new Androidapplication. The plugin routinely generates the suitable task structure in your application, and maintains the assets compiled for you robotically.

It is still a terrific concept to recognize what is going on although. Take a have a look at Overview of an AndroidApplication to understand the fundamentals of how an Android application works.

It is also recommended that you test the ApiDemos application and the alternative sample applications in the samples/ folder inside the SDK.

Finally, a remarkable manner to began with Android improvement in Eclipse is to comply with both the Hello Android and Notepad code tutorials. In particular, the begin of the Hello Android educational is an tremendous advent to creating a new Android utility in Eclipse.

Symbian Interview Questions
Question 10. Can I Write Code For Android Using C/c++?

Answer :

Android programs are written using the Java programming language.Android consists of a fixed of middle libraries that provides maximum of the functionality to be had inside the middle libraries of the Java programming language.Every Android utility runs in its personal procedure, with its very own instance of the Dalvik digital device. Dalvik has been written so that a device can run multiple VMs efficaciously. The Dalvik VM executes documents within the Dalvik Executable (.Dex) format which is optimized for minimal reminiscence footprint. The VM is sign in-primarily based, and runs classes compiled with the aid of a Java language compiler which have been converted into the .Dex layout through the protected ?Dx? Device.Android simplest supports applications written the use of the Java programming language presently.

IOS Tutorial
Question 11. What Is The Ttl (time To Live)? Why Is It Required?

Answer :

TTL is a fee in facts packet of Internet Protocol. It communicates to the network router whether or no longer the packet ought to be in the network for too lengthy or discarded. Usually, information packets might not be transmitted to their supposed destination inside a stipulated period of time. The TTL price is ready by means of a device default value which is an 8-bit binary digit field inside the header of the packet. The reason of TTL is, it might specify sure time restrict in seconds, for transmitting the packet header. When the time is exhausted, the packet might be discarded. Each router receives the subtracts count number, when the packet is discarded, and while it becomes 0, the router detects the discardedpackets and sends a message, Internet Control Message Protocol message returned to the originating host.

TTL(time to stay) apart from figuring out the existence time of a packet in a community additionally facilitates in averting the wastage of bandwith

iOS Development with Swift 2 Interview Questions
Question 12. How Is Nine-patch Image Different From A Regular Bitmap?

Answer :

It is a resizable bitmap aid that may be used for backgrounds or other snap shots at the device. The NinePatch magnificence permits drawing a bitmap in nine sections. The four corners are unscaled; the 4 edges are scaled in a single axis, and the middle is scaled in both axes.

Core Java Interview Questions
Question 13. Explain Ip Datagram, Fragmentation And Mtu ?

Answer :

IP datagram can be used to explain a part of IP facts. Each IP datagram has set of fields arranged in an order. The order is precise which helps to decode and examine the flow without difficulty. IP datagram has fields like Version, header duration, Type of provider, Total period, checksum, flag, protocol, Time to live, Identification, supply and destination ip address, padding, alternatives and payload.

MTU:- Maximum Transmission Unit is the dimensions of the biggest packet that a communication protocol can pass. The size may be fixed with the aid of some standard or determined at the time ofconnection

Fragmentation is a manner of breaking the IP packets into smaller pieces. Fragmentation is needed while the datagram is greater than the MTU. Each fragment will become a datagram in itself and transmitted independently from source. When obtained through destination they are reassembled.

Question 14. What Is Sticky Intent?

Answer :

Is there anyway to determine if an Intent exceeded right into a BroadcastReceiver's onReceive is the result of a sticky Boradcast Intent, or if it became simply sent.

Question 15. User-generated Content: Report Abuse Which Is The Better Phone - The Iphone Or The Droid?

Answer :

The iphone 4 is better than every other cellphone. For one it's miles made out of the equal fabric they use in helicopter and educate windows.(atleas from what i haerd)another thing is that the iphone has a higher app market. With over 300,000 apps it's far far higher than the droids 70,000. Also it comes with greater accesories and has an antenna to offer better sign while the droid doesn't. People say it has a horrific connection however i suppose not for the reason that i've already used it. And last but no longer leats better resolution. It can have a smaller display screen however still its pictures are higher.So all of it depends on you each one has its united statesand its downs however i might go with iphone four over any phone specifically the "all new droid x"

Question 16. How Long Does It Take To Build An App?

Answer :

Depending on the complexity and how quickly you respond to us you may have an app built in about a month.

Question 17. How Much Does Mobile Application Development Cost? That Is A Bit Like Asking: How Much Does A Truck Cost?

Answer :

The solution is that it relies upon at the truck. Your desires are unique and your app wishes to fulfill best the ones needs. A small Toyota will cost a lot less than a huge semi tractor trailer. A tractor trailer is tremendous if you need to haul goods across the usa however dont try to take it on a Saturday night date. We help you to avoid developing too much - or too little app. This continues fees low.

Having us create a custom smartphone app is enormously low-priced. Many agencies discover their app costs less than even a small radio or newspaper marketing campaign. Unlike a radio campaign, the app?S usefulness does no longer cease with the ultimate industrial. Once it's far created an app can upload to your bottom line for a completely long time. Our purpose is to connect your target market with your coins sign in no matter in which they may be. With a phone app you deliver your clients get admission to to you at the exact second their shopping for selection is the strongest.

Question 18. Describe The Apk Format.

Answer :

The APK file is compressed the AndroidManifest.Xml file, application code (.Dex files), useful resource files, and different files. A challenge is compiled right into a unmarried .Apk report.

BLACKBERRY Interview Questions
Question 19. Is Sim Pin Code Working?

Answer :

It's speculated to be running, yes, however when you have ANY issues please DISABLE SIM PIN in WinMo (SIM PIN works on the SIM, but you need WinMo UI to disable it)

Question 20. What Is The Future Scope Of Mobile Application Developers?

Answer :

Future of the mobile application improvement is bright

Question 21. What Is The Mobile Application Development All About?

Answer :

In the last two years, a number of innovation has come in the mobile computing global. Apple has launched very innovative cellular smartphone, iphone and ipad along with app save. Google released Android in Nov 2007. Blackberry released SDK and app international. Microsoft has give you cellphone 7 framework. Almost every kind of cellular can be programmed the usage of J2ME. Making applications for these types of gadgets is Mobile utility improvement.

Question 22. What Is The Demand Of Mobile Application Developers?

Answer :

Desktop based totally IT application is present but the cell is destiny. All the packages that had been madeto work simplest on desk top are being ported to cell. In the approaching 10 years, computer systems will get replaced completely with cellular, and then all the applications will be designed mainly for cell. The call for for cell primarily based trained engineers are increasing each yr. Now after the launch of ipad by way of Apple, it'll be even greater. Therefore; the gextgen generation can be nothing else than cell. The demand is anticipated to grow 70 folds inside the coming 4 years.

Question 23. What Is The Risk In Blocking The Main Thread When Performing A Lengthyoperation Such As Web Access Or Heavy Computation?

Answer :

Application_Not_Responding exception could be thrown in an effort to crash and restart the software.

Question 24. What Is A Dalvik ?

Answer :

The name of Androids virtual machine. The Dalvik VM is an interpreter-simplest virtual machine that executes documents inside the Dalvik Executable (.Dex) layout, a format this is optimized for green storage and reminiscence-mappable execution. The virtual gadget is sign up-based totally, and it could run classes compiled with the aid of a Java language compiler that have been converted into its local format the use of the protected ?Dx? Device. The VM runs on top of Posix-compliant running structures, which it relies on for underlying capability (including threading and coffee stage reminiscence management). The Dalvik core magnificence library is intended to provide a familiar development base for those used to programming with Java Standard Edition, however it's far geared in particular to the needs of a small cell tool.

IOS Interview Questions
Question 25. What Features Are In A Release?

Answer :

Generally, it's very hard to detail them, unless there is a substantial new function (wherein case, that will be very well advertised!). Usually it is minor velocity improvements, trojan horse fixes and so forth... And on occasion, new bugs are delivered (so bear that during thoughts)

Question 26. When Will It Be Available In A Rom?

Answer :

No time quickly. Folks are working on it, but you'll need a lot of endurance before it (if ever) arrives.

Question 27. I Keep Hearing 'popping/clicking' Sounds From The Speaker?

Answer :

This is a regarded annoyance on some gadgets, believed to be related to electricity management switching the speaker on and stale (now not confirmed), it really appears worse in silent mode (ironically). If you enjoy this, you are now not by myself... Maximum customers do. When a fix is prepared, it'll be introduced here.

Symbian Interview Questions
Question 28. How Much Revenue Share Does The Developer Get?

Answer :

The developer receives 70% sales generated from every Android software buy even as the relaxation is used for settlement fees. Google doesn't take a dime out of this.

Question 29. Explain Seapine Software?

Answer :

Seapine's software improvement and checking out equipment streamline your development procedure, saving you tremendous money and time. Enjoy characteristic-rich tools which might be bendy enough to work in any software program improvement surroundings. With Seapine incorporated tools, every step in the developmentprocess feeds important information into the subsequent step, letting you attention on growing excessive pleasant software in much less time.

Question 30. Why Is List View Not Recommended To Have Active Components?

Answer :

Clicking on the active textual content field will pop up the software keyboard however this can resize the listing, putting off awareness from the clicked detail.

Question 31. Why Is Open Platform Good For The Mobile Operators?

Answer :

An open platform would foster faster innovation, a couple of software program versions, higher customisation options, lower costs, which might convey down the general service and handset costs at the same time as boostingsales.

Question 32. Describe A Real Time Scenario Where Android Can Be Used?

Answer :

Imagine a scenario which you are in a rustic wherein no one knows the language you communicate and also you can't examine or write. However, you have cellular phone with you.

With a cell phone with android, the Google translator translates the data of one language into every other language by using XMPP to transmit records. You can kind the message in English and select the language which is thought by means of the citizens of the united states of america on the way to attain the message to the citizens.

Question 33. Why Is Open Platform Good For Developers?

Answer :

Developers might be able innovate hastily because they may have complete API get admission to tohandset capabilities which might be internet-geared up. They will experience expanded productiveness because they will have complete and easy-to-use developer equipment. And because open source gives a deeper knowledge of the underlying mobile platform, they are able to better optimise their applications. Finally, the distribution and commercialisation of mobile apps might be much less steeply-priced and easier.

IOS Development with Swift 2 Interview Questions
Question 34. How Will You Record A Phone Call In Android? How To Get A Handle On Audiostream For A Call In Android?

Answer :

Permissions.PROCESS_OUTGOING_CALLS: Allows an application to screen, alter, or abort outgoingcalls.

Question 35. What Is An Ddms?

Answer :

Dalvik Debug Monitor Service, a GUI debugging application shipped with the SDK. It offers display capture, log sell off, and system exam competencies.

Question 36. What Are The Advantages Of Android?

Answer :

The following are the blessings of Android:
* The consumer will be benefited from wide variety of cellular programs to pick out, considering themonopoly of wi-fi carriers like AT&T and Orange can be broken by using Google Android.
* Features like climate info, live RSS feeds, starting display, icon on the hole display screen can be custom designed
* Innovative products just like the region-aware offerings, place of a close-by comfort keep and many others., are some of the additive centers in Android.

Question 37. Does Android Support The Bluetooth Serial Port Profile?

Answer :

Yes.

Question 38. What Is The Android G1 Phone?

Answer :

The Android T-Mobile G1 cellphone is the world's first Android-powered mobile smartphone advanced through HTC and T-Mobile.

Question 39. Which Is The Virtual Machine Used To Run The Android Apps?

Answer :

The VM used is known as Dalvik, so named after the ancestral roots of its creator, because the story is going.

Question 40. Are The Android Apps First Scrutinised By Google?

Answer :

No the Android packages may be directly posted on the Android Market after you are registered as a developer after paying the $25 application charge.

Question forty one. What Is An Intent Receiver?

Answer :

An software magnificence that listens for messages broadcast by way of calling Context.BroadcastIntent

Question 42. What's The Difference Between File, Class And Activity In Android?

Answer :

File - It is a block of arbitrary information, or aid for storing information. It can be of any type.
Class - Its a compiled form of .Java document . Android finally used this .Elegance documents to provide an executable apk.
Activity - An hobby is the equal of a Frame/Window in GUI toolkits. It isn't always a document or a record type it's far only a class that may be prolonged in Android for loading UI elements on view.

Question 43. How To Select More Than One Option From List In Android Xml File? Give An Example.

Answer :

Specify android identification, layout top and width as depicted within the following instance.

<ListView android:id="@+id/ListView01" 
android:layout_height="wrap_content" 
android:layout_width="fill_parent"></ListView>
Question forty four. What Languages Does Android Support For Application Development?

Answer :

Android packages are written the usage of the Java programming language.

Question 45. What Are The Dialog Boxes That Are Supported In Android? Explain.

Answer :

Android helps 4 conversation bins:
AlertDialog : An alert conversation container helps 0 to 3 buttons and a listing of selectable elements, which includes test bins and radio buttons. Among the other conversation containers, the maximum counseled dialog field is the alert dialog field.

ProgressDialog: This conversation container displays a progress wheel or a progress bar. It is an extension of AlertDialog and helps including buttons.

DatePickerDialog: This dialog field is used for selecting a date by means of the consumer.

TimePickerDialog: This dialog box is used for choosing time by using the consumer.

Question forty six. What Virtual Machine Android Runs On?

Answer :

Dalvik virtual machine

Question 47. What Are The Differences Between A Domain And A Workgroup?

Answer :

In a domain, one or more pc can be a server to manipulate the community. On the alternative hand in aworkgroup all computers are peers having no manipulate on every different. In a site, consumer doesn?T needan account to logon on a specific pc if an account is to be had at the area. In a work organization consumer desires to have an account for each computer. In a website, Computers can be on one-of-a-kind nearby networks. In a piece organization all computer systems desires to be a part of the identical nearby community.

Question 48. How To Remove Desktop Icons And Widgets?

Answer :

Press and Hold the icon or widget. The phone will vibrate and on the bottom of the telephone you'll see anoption to dispose of. While nonetheless protecting the icon or widget drag it to the cast off button. Once get rid of turns purple drop the item and it's far long gone.

Question 49. What Is .Apk Extension?

Answer :

The extension for an Android package deal document, which generally incorporates all the documents related to a unmarried Android utility. The report itself is a compressed series of an AndroidManifest.Xml file,utility code (.Dex files), resource files, and other documents. A undertaking is compiled right into a unmarried .Apk report.

Question 50. What Is A Layout Resource?

Answer :

An XML file that describes the layout of an Activity screen.

Question fifty one. What Is A Manifest ?

Answer :

An XML file associated with each Application that describes the numerous activies, motive filters, services, and other objects that it exposes.

Question fifty two. What Is A Theme ?

Answer :

A set of residences (text size, historical past coloration, and so on) bundled collectively to outline diverse default display settings. Android gives some wellknown themes, indexed in R.Style (beginning with ?Theme_?).

Question fifty three. What Is An Uris?

Answer :

Android uses URI strings both for inquiring for records (e.G., a list of contacts) and for requesting actions (e.G., beginning a Web page in a browser). Both are valid URI strings, however have one of a kind values. All requests for records should start with the string ?Content material://?. Action strings are legitimate URIs that may be treated accurately via programs on the tool; as an instance, a URI beginning with ?Http://? Might be treated through the browser.

Question fifty four. Can An Application Be Started On Powerup?

Answer :

Yes.

Question fifty five. What Is An Action?

Answer :

A description of something that an Intent sender desires.

Question fifty six. What Is Activity?

Answer :

A single display screen in an software, with helping Java code.

Question fifty seven. What Is Intent?

Answer :

A class (Intent) describes what a caller desires to do. The caller sends this rationale to Android's cause resolver, which finds the most suitable hobby for the cause.

Question fifty eight. What Is A Resource?

Answer :

A person-supplied XML, bitmap, or different record, injected into the software build system, which could later be loaded from code.

Question fifty nine. What Is A Sticky Intent?

Answer :

sendStickyBroadcast() plays a sendBroadcast (Intent) that is "sticky," i.E. The Intent you're sending remains around after the broadcast is whole, in order that others can fast retrieve that records through the return cost of registerReceiver (BroadcastReceiver, IntentFilter). In all other approaches, this behaves the same as sendBroadcast (Intent).
One example of a sticky broadcast sent thru the operating system is ACTION_BATTERY_CHANGED. When you name registerReceiver () for that action -- regardless of a null BroadcastReceiver -- you get the Intent that was closing broadcast for that movement. Hence, you can use this to find the state of the battery without always registering for all destiny kingdom changes in the battery.

Question 60. What Is The Open Handset Alliance?

Answer :

The OHA is a consortium of 30 technology and cell companies which have joined palms to accelerate innovation in cell generation and on the equal time offer the end customers a better, costeffective and richer cell experience.

Question 61. What Innovations The Oha Members Strive To Achieve?

Answer :

The OHA contributors have endeavored to increase Android, the open supply cellular platform including an OS, net browser and key packages. Different businesses have unique contributions to make and roles to play. For example, the software program agencies like Google are developing the needful software, the hardware companies the chipsets and the mobile corporations are ensuring like minded handsets for Android.

Question sixty two. Why An Open Source Platform Would Be Beneficial To Consumers?

Answer :

Open supply platform will make sure less expensive mobile handsets and offerings coupled with richer consumer experience inside the form of a friendlier interface, cool packages and an more desirable surfing enjoy.

Question sixty three. How Will Apps Change With Android 2.2?

Answer :

The solution is that with Froyo, Google's giving us a bunch of new ways to take advantage of apps from the Android Market and beyond. The highlights:SD card installations:  you will subsequently be able to set up apps to your SD card, smashing the gap obstacles of Android versions beyond. You'll be capable of pick out in which you need each app to be installed - SD card or inner garage - and even toggle it backward and forward with multiple clicks later.




CFG