File Name: android interview question and answers .zip
In the year Android came as a popular computing platform, which is based on the Linux operating system. In the smartphone market, it became one of the most leading names that managed to change the whole. In the last ten years time, it grabs the majority of market share sharing with iOS and has effectively become the world's most popular operating system.
With the maturity of Android, it is finding its new way into a variety of devices, not just on smartphones but also includes televisions, projectors, automobiles, and even now the vehicles.
Today with the advent of the Android platform, Android developers are huge in demand and every sector and industry is looking to recruit them in-house. If you aspire to be an Android developer, then this is just the place for you.
Given below is the list of questions, which answers both basic and advanced concepts of Android. These questions if well prepared before an interview shall give an extra edge to the candidate and give confidence of facing the panel:. ANR is an abbreviation for Application not responding that describes an unresponsive Android app.
The DVM executes Dalvik bytecode. Build Type is a build and packaging settings like signing configuration for a project. For instance, debug and release build types. The debug build type will use an android debug certificate for packaging the APK file. While the release build type will use a user-defined release certificate for signing and packaging the APK. An Android activity is a screen of the Android app's user interface.
It is similar to windows in a desktop application. An Android app may contain one or more activities that mean one or more screens. Android uses Intent for the communication between the components of an Application. The intent is the object which is used in android for passing the information among Activities in an Application.
It also provides connectivity between two apps. It also provides platform libraries that you can use to manage native activities and access physical device components, such as sensors and touch input. The Android Emulator imitates Android devices on your system. Therefore, users will be able to check your application on a spread of devices and Android API levels without having to possess every physical device.
The emulator provides the majority of the capabilities of a real Android device. Android is an open-source operating system that can be useful for many tasks. An android application will undergo various states that are associatively called as Android Activity Life Cycle.
Services in Android are a component that acts as an application to run in the background in order to perform long-running operation tasks. Android AsyncTask going to do background operation on the background thread and update on the main thread. In android, We can't directly touch the background thread to the main thread in android development. IntentService is a direct subclass for Services that handle asynchronous requests on demand.
Clients send requests through Context. It is born to make things easier. It is also used to perform a certain task in the background. The instance of IntentService terminates itself automatically when needed. A Handler is used to send and process Message and Runnable objects associated with a thread's MessageQueue. When a Handler created default bound with a Looper class. It will deliver messages and runnable to that Looper's message queue and execute them on Looper's thread.
Handlers are mainly used to Update the User Interface from a background thread, Enqueue a task for a different thread and Schedule a task for a specified time. The onTrimMemory int level is used when the operating system has determined that a process to trim unneeded memory from its subprocess.
You can avoid ANR to perform long-running operations on the worker thread, not on the main thread. To create a worker thread, we can use AsyncTask class for long-running operations like File uploading, File downloading, etc. The Android software development kit SDK consists of a comprehensive set of development tools that includes a debugger, libraries, a handset emulator based on QEMU, documentation, sample code, and tutorials. A Pending Intent is an action to require in the future.
It allows you to pass a future Intent to a different application and permit that application to execute the Intent. Every app project has an AndroidManifest. This file contains information about your package, Android operating system, the Android build tools, Google Play, and other including components of the application such as activities, content providers, services, broadcast receivers, etc.
The Intent is used with sticky broadcast, which is called sticky intent. This intent will stick with the android system for future broadcast receiver requests. A Fragment represents a reusable portion of your app's User Interface. Retained Fragment consists of the configuration change that causes the underlying Activity to be destroyed. The term "retained" refers to the fragment that will not be destroyed on configuration changes.
The Android platform provides several sensors that are used to monitor the motion of a device. The sensors' possible architectures vary with sensor types such as the gravity, linear acceleration, rotation vector, significant motion, step counter, and step detector sensors that are either hardware-based or software-based. In an application, An Intent is a messaging object that can be used to request an action from another app component.
It specifies the type of intents that the component would like to receive. For instance, you make it possible for other apps to directly start your activity with a certain kind of intent by declaring an intent filter for an activity. SQLite is an embedded SQL database engine with multiple tables, indices, triggers, and views, contained in a single disk file.
SQLite modifies data directly to ordinary disk files. AppCompatActivity is the base class for activities with the support library action bar features. ActionBar can be added to your activity by extending this class for your activity and setting the activity theme to Theme when running on API level 7 or higher. Proguard detects and removes unused classes, fields, methods, and attributes. Mobile app development companies use the Proguard in android, it optimizes bytecode and removes unused instructions.
It renames the remaining classes, fields, and methods by using short meaningless names. An android application includes Activities that form a stack like a deck of cards.
Then they will form a stack such as:. Android Toast displays information for a short period of time that contains a message to be displayed quickly and disappears after some time. It also used to show notifications for a particular interval of time at the bottom of the screen by default. StateListDrawable is a java class of Android, that is used for drawable contents in an application. The drawer Layout is the root layout. It defines a FrameLayout and a Navigation View. In Navigation View we set the items from the menu file and FrameLayout is used to replace the Fragments on the click of menu items.
Android Jetpack is a set of Android components, tools, and guidance inspired by the backward compatibility of the Support Library and Android Architecture Components that are platform-independent, allowing your app to run on multiple Android platforms.
The bound service is a server in a client-server interface that allows components such as activities to bind to the service, send requests, receive responses, and perform interprocess communication IPC. A DialogFragment is a fragment that floats on top of the current activity window and displays a modal window. An instance of DialogFragment can be used to display an existing Dialog implementation dialog or a custom view hierarchy by using the Dialog class that is the base class for implementing a dialog.
The Presenter acts as a mediator between model and view. All your presentation logic belongs to the presenter which is responsible for querying the model and updating the view, reacting to user interactions, and updating the model.
You can avoid continuous allocation and deallocation of memory in your application by using the Bitmap pool, you can reduce GC overhead, which results in a smooth-running application. Android Recycler View is a version of ListView. It has improved performance and other benefits. You can use RecyclerView and CardView together, which creates both lists and grids very easily.
A view holder design pattern is used to speed up the rendering of your ListView to make it work smoothly, findViewById is quite expensive when used each time a list item is rendered, it must traverse your layout hierarchy. Rooting is the process of attaining users privileged control known as root access over various Android subsystems to allowing Android mobile operating systems to run on smartphones, tablets, and other devices.
Android WebView is a system component that allows Android apps to display web content. It is pre-installed on your device and should be kept up to date to ensure you have the latest security updates and other bug fixes.
A SurfaceView is a view in a view hierarchy that has its own separate Surface. It also provides a dedicated drawing surface embedded inside of a view hierarchy.
Scannable is a Spanned, adding in the ability to modify the spans to add or remove formatting, but not to modify the text itself. Samsung DeX is a feature that is included on some high-end Samsung handheld devices. It enables users to extend their device into a desktop-like experience by connecting a keyboard, mouse, and monitor. Samsung DeX is also a platform that turns your smartphone into a desktop computing experience. The Espresso is a testing framework for Android. It is an easier way to write reliable user interface tests.
It automatically synchronizes your test actions with the UI of your application. It also ensures that your activity is started before the tests run. Android is an open-sourced operating system by Linux that is primarily used in mobile devices like cell phones and tablets.
This Linux kernel based system is equipped with high and advanced components that allow developers to create and run apps. Therefore performs the basic as well as the advanced functions. Android application components are the building block essentially used in the Android application.
Here is a list of 50 important Android Operating system interview questions with their answers. Android is the most popular operating system used in mobile phones. It started a new era on mobile industry with smartphones and tablets. The main feature was its touch screen. Now most of the IT companies are working with Android Apps developments. Android is a mobile operating system which was designed and built by Google, using the Linux Kernel and intended to mainly for touchscreen mobile devices like tablets and Smartphones.
Here are the 21 most frequently asked Android interview questions comprising both basic and advanced levels and their perfect answers. Feel free to share your comments and queries. Happy learning! Although both Android and iOS Developers are in high demand, there is more requirement for Android Developers in the market. It is the most commonly used operating system in the world today.
50 Android Interview Questions & Answers · 1) What is Android? · 2) What Is the Google Android SDK? · 3) What is the Android Architecture? · 4).
There are four Java classes related to the use of sensors on the Android platform. List them and explain the purpose of each. A ContentProvider manages access to a structured set of data. It encapsulates the data and provide mechanisms for defining data security. ContentProvider is the standard interface that connects data in one process with code running in another process.
It is an open-sourced operating system that is used primarily on mobile devices, such as cell phones and tablets. It is a Linux kernel-based system that's been equipped with rich components that allows developers to create and run apps that can perform both basic and advanced functions. It contains a graphical interface that emulates an Android driven handheld environment, allowing them to test and debug their codes.
Finding either a new job as a fresher or moving from one to another as an experienced professional has turned out to be more tedious with the increase in competition especially in the IT sector. It is equally important to prepare yourself in a differentiating manner while applying for any kind of jobs. Wisdomjobs provides you with all assistance needed to prepare for Android jobs. Look for an Android jobs interview questions and answers page and prepare yourself to get your dream job in time either as a fresher or an experienced candidate. With our interview questions that are well arranged at different difficulty levels, your job hunt will be as easier as that you could crack the interview right in the first attempt. Answer : Android is a stack of software for mobile devices which has Operating System, middleware and some key applications. The application executes within its own process and its own instance of Dalvik Virtual Machine.