In this post, you will get the most important and top Android Interview Questions and Answers, which will be very helpful and useful to those who are preparing for jobs.
Q1) Explain Android
Android is very famous for Tablets and smartphones and this is an open-source operating system. The operating system of Android is Linux Kernel. The developers are developing the programs or functions with the help of Android operating system to perform both advanced and basic operations on Smartphones.
Q2) Explain Android SDK
Android SDK is an efficient set of tools to write an app or develop a mobile application. This tool has a Graphical User Interface emulating an android environment. This kind of an emulator stands out to be an actual mobile where the developers can write the code and test the written the code.
Q3) List out the different Android version along with its name.
Android 4.0 to 4.0.4 – Ice Cream Sandwich, Android 4.1 to 4.3 – Jelly Bean, Android 4.4 to 4.4.4 – Kitkat, Android 5 to 5.1.1 – Lollipop, Android 6 to 6.0.1 – Marshmallow, Android 7.0 to 7.1.2 – Nougat, and Android 8.0 – Oreo are the different android version and its names.
Q4) Which language is supporting Android development?
Android development widely uses the language Java. In addition, it supports C or C++ when using Android SDK. This really enhances the performance speed.
Q5) What are the layers in the Android architecture?
Linux Kernel, Hardware Abstraction Layer, Android Runtime, Application Framework and Applications are the layers in the Android Architecture.
Q6) If you start a new project in Android, what are the required components?
The components essential to start a new project in Android are build/, res/, manifest, assets/ and src/.
Q7) List out the Android vital core components
Services, Fragment, Activity, Content Provider and Intents are the core components of Android.
Q8) Describe services in Android
An android component that runs in the background and acting autonomously without providing any user interface are called services. As the services is recognised to run in the background, users can easily access any apps and continue to perform their own work.
Q9) What are the different states of Activity Lifecycle in Android?
The different states of Activity Lifecycle in Android are given below:
- onCreate()
- onStart()
- onRestart()
- onResume()
- onPause()
- onStop()
- onDestroy()
Q10) Describe Intent of Android
When there is a need for a user to navigate from one activity to the other one, Android is holding the Intent class. Intent is the one that displays notification to the users from the device and if required, users can act on that notification.
Q11) Provide the types of Intents
Implicit and Explicit Intents are the two (2) types of Intents available in Android.
Q12) Define Implicit Intents
The intents that calls the system components are called Implicit Intents.
Q13) Define Explicit Intents
The intents that invoke the Activity are called Explicit Intents.
Q14) What is the use of permission setup in app development?
Only the authorized users are permitted to use the code and data once the permission setup is completed in app development.
Q15) Mention the database which is used for android platform
Android platform make use of SQLite database, which is a serverless and open-source database.
Q16) Give the abbreviation of ANR
ANR – Application Not Responding. The Android platform displays a pop-up when too many functions are performed by the application at a time and at times, users will not receive any response from the system. Such kind of a pop-up notification is called ANR.
Q17) List out the dialog boxes supported by Android
TimePickerDialog, AlertDialog, DatePickerDialog, and ProgressDialog are the dialog boxes supported by Android platform.
Q18) What is the abbreviation of ADB?
ADB stands for Android Debug Bridge, a command line tool performing shell commands. To enable the communication directly between the emulator parts, ADB is used.
Q19) Explain Orientation
Orientation which is available in smartphones these days provides the ability for screen rotation. Users can rotate the screen between vertical or horizontal mode.
Q20) How many types of orientations are available in Android?
There are two (2) types of Orientations are available in Android, namely Portrait and Landscape.
Q21) What is the method used to set the orientation?
The method used to set the orientation is ‘setOrientation’ and this can easily set the screen configurations.
Q22) What is the method used while changing the orientation from one to the other?
The method ‘onCreate()’ is used while changing the orientation from vertical to horizontal or vice-versa.
Q23) Describe ActivityCreator
ActivityCreator is a shell script and batch file, helpful for creating a new project in Android. In Android SDK, ActivityCreator is replaced by “Create New Project”.
Q24) Give the abbreviation for AIDL
AIDL – Android Interface Definition Language. This is used to simplify the communication between service and the client. Also, the inter-process communication can be used to pass the information.
Q25) List out the data types which are supported by AIDL
Map, String, Data types of Java, charSequence, and List are the data types supported by AIDL.
Q26) What is AndroidManifest.xml file in Android?
Before running an app code, every android system should ensure to have AndroidManifest.xml file in the root directory. This file contains information on Android components like Content Providers, Activity, Broadcast Receivers, Services, etc and the package name.
Q27) Mention the tool names that is used for debugging in Android
Few tool names used for debugging in Android are given below:
- Android Debug Bridge
- iOS simulator
- Android DDMS
- Remote Debugging
- Eclipse with ADT
Q28) What are the mobile automation testing tools in market?
Robotium, Appium, Calabash, and KIF are the free automation tool. SeeTest, Silk Mobile and Ranorex are the paid tools.
Q29) Provide few details on how to troubleshoot android apps when the users faces the crashing regularly.
Users must free up the memory space and then must clear the usage of app data. Try to manage the memory often and perform compatibility testing using different mobile devices.
Q30) If there is a leak in memory, how will you find it in an Android mobile app?
Android Device Manager is used to detect the memory leakage on all Android mobile apps.
Q31) What is the abbreviation of DDMS?
DDMS stands for Dalvik Debug Monitor Server, which is a debugging tool used by Android Studio.
Q32) Is it possible to debug on both emulators and real devices with the help of DDMS?
Yes, it is possible to debug on both emulators and real devices with the help of DDMS.
Q33) List out the various data storage options available on Android
Internal Storage, SharedPreference, External Storage and SQLite are the different storage options.
Q34) What are sensors?
To measure motion, orientation and few other conditions of an android devices, we do have a feature called built-in sensors.
Q35) What are the sensor categories available in Android devices?
Position Sensors, Motion Sensors and Environmental Sensors are the three categories of sensors available in Android devices.
Q36) Provide the Java classes available with respect to the Android sensors.
SensorEvent, Sensor Manager, SensorEventListener and Sensor are the Javaclasses available with respect to the Android sensors.
Q37) What is the abbreviation of NDK?
NDK – Native Development Kit.
Q38) What is the use of NDK?
If you want to use the native language like C or C++ to develop a part of an app, NDK is very much helpful.
Q39) What is the abbreviation of APK?
APK stands for Android Packaging Key.
Q40) What is the abbreviation of ADT?
ADT – Android Development Tool, which is useful in developing and testing the applications.
Q41) In Android, which kernel is used?
Customised Linux 3.6 Kernel is used in Android.
Q42) In Android, what are the flag types used to run an application?
FLAG_ACTIVITY_CLEAR_TOP and FLAG_ACTIVITY_NEW_TASK are the two types of flags.
Q43) Explain sleep mode process in Android
If sleep mode is ON, CPU is made to sleep and no commands are accepted from android devices, excluding alarm and radio interface layer.
Q44) Provide few exceptions available in Android
SurfaceHolder.BadSurfaceTypeException, Inflate Exception, WindowManager.BadTokenException and Surface.OutOfResourceException are the exceptions available in Android.
Q45) Provide the three CPU architectures of Android
ARMv7, ARMx86, and ARM64 are the three (3) CPU architectures of Android.
Q46) What is the reason for not running bytecode in Android?
Rather using Java Virtual Machine (JVM), Dalvik Virtual Machine is used by Android. Hence, it is not possible to run bytecode in Android.
Q47) What are the Launch modes available in Android?
SingleTop, SingleInstance, Standars and SingleTask are the four (4) Launch modes available in Android.
Q48) What is the use of Thread?
If there are long running operations from main thread, Thread is used to separate those to improve the performance.
Q49) Define Handlers in Android
To manage threads, handlers are used. Handlers permits the communication between main thread and background thread. Users prefer handlers when there is a need to perform background task frequently for a given intervals in minutes.
Q50) What are the services available in Android?
Bound Services, Background Services and Foreground Services are the three (3) services available in Android.
