Android Interview Questions: The questions that are asked in your interview decide your future. Reading this article will help you in understanding how to crack interviews easily and how to clear all the doubts you have before entering into an interviewing hall. The Android Interview questions that we have been made by the experienced and professional candidates who are or have worked in this specific industry for years now. The Android Interview Questions will help you in answering all sorts of questions asked during an interview and help you in taking the next step towards your future.
Android is an open-source platform that is primarily used in Smartphones or Tablets as an Operating System. This operating system is based on the concept of the Linux Kernel. Using this operating system, an Android developer develops all the necessary programs and functions that have the ability to perform the basic and advanced level of operations on your phone. It’s equipped with all sorts of rich components that make the job easier for the developers as well as the testers.
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 thats been equipped with rich components that allow developers to create and run apps that can perform both basic and advanced functions.
The Google Android SDK is a toolset that developers need in order to write apps on Android-enabled devices. It contains a graphical interface that emulates an Android-driven handheld environment, allowing them to test and debug their codes.
Android Architecture is made up of 4 key components:
The Android Framework is an important aspect of Android Architecture. Here you can find all the classes and methods that developers would need in order to write applications on the Android environment.
AAPT is short for Android Asset Packaging Tool. This tool provides developers with the ability to deal with zip-compatible archives, which includes creating, extracting as well as viewing its contents.
The emulator lets developers "play" around an interface that acts as if it were an actual mobile device. They can write and test codes, and even debug. Emulators are a safe place for testing codes especially if it is in the early design phase.
An activityCreator is the first step towards the creation of a new Android project. It is made up of a shell script that will be used to create a new file system structure necessary for writing codes within the Android IDE.
Activities are what you refer to as the window to a user interface. Just as you create windows in order to display output or to ask for input in the form of dialog boxes, activities play the same role, though it may not always be in the form of a user interface.
Intents display notification messages to the user from within the Android-enabled device. It can be used to alert the user of a particular state that occurred. Users can be made to respond to intents.
Activities can be closed or terminated anytime the user wishes. On the other hand, services are designed to run behind the scenes and can act independently. Most services run continuously, regardless of whether there are certain or no activities being executed.
These are the essential items that are present each time an Android project is created:
Below stated are the available instances:
Containers, as the name itself implies, holds objects and widgets together, depending on which specific items are needed and in what particular arrangement that is wanted. Containers may hold labels, fields, buttons, or even child containers, as examples.
Orientation, which can be set using setOrientation(), dictates if the LinearLayout is represented as a row or as a column. Values are set as either HORIZONTAL or VERTICAL.
Developers can write and register apps that will specifically run under the Android environment. This means that every mobile device that is Android enabled will be able to support and run these apps. With the growing popularity of Android mobile devices, developers can take advantage of this trend by creating and uploading their apps on the Android Market for distribution to anyone who wants to download it.
Given that Android is an open-source platform and the fact that different Android operating systems have been released on different mobile devices, theres no clear-cut policy to how applications can adapt to various OS versions and upgrades. One app that runs on this particular version of Android OS may or may not run on another version. Another disadvantage is that since mobile devices such as phones and tabs come in different sizes and forms, it poses a challenge for developers to create apps that can adjust correctly to the right screen size and other varying features and specs.
Adb is short for Android Debug Bridge. It allows developers the power to execute remote shell commands. Its basic function is to allow and control communication towards and from the emulator port.
ANR is short for Application Not Responding. This is actually a dialog that appears to the user whenever an application has been unresponsive for a long period of time.
Among the different elements, the and elements must be present and can occur only once. The rest are optional and can occur as many times as needed.
Escape characters are preceded by double backslashes. For example, a newline character is created using \\n
Permissions allow certain restrictions to be imposed primarily to protect data and code. Without these, codes could be compromised, resulting in defects in functionality.
Because every component needs to indicate which intents they can respond to, intent filters are used to filter out intents that these components are willing to receive. One or more intent filters are possible, depending on the services and activities that are going to make use of it.
A call to onStop method happens when an activity is no longer visible to the user, either because another activity has taken over or if in front of that activity.
Yes, there are actually instances wherein some qualifiers can take precedence over locale. There are two known exceptions, which are the MCC (mobile country code) and MNC (mobile network code) qualifiers.
There are 4 possible states:
One technique that prevents the Android system from concluding a code that has been responsive for a long period of time is to create a child thread. Within the child thread, most of the actual workings of the codes can be placed, so that the main thread runs with minimal periods of unresponsive times.
Dalvik serves as a virtual machine, and it is where every Android application runs. Through Dalvik, a device is able to execute multiple virtual machines efficiently through better memory management.
This file is essential in every application. It is declared in the root directory and contains information about the application that the Android system must know before the codes can be executed.
The following are steps to be followed prior to actual application development in an Android-powered device.
Ans: When default resources, which contain default strings and files, are not present, an error will occur and the app will not run. Resources are placed in specially named subdirectories under the project res/ directory.
Assuming that all of these multiple resources are able to match the configuration of a device, the locale qualifier almost always takes the highest precedence over the others.
The ANR dialog is displayed to the user based on two possible conditions. One is when there is no response to an input event within 5 seconds, and the other is when a broadcast receiver is not done executing within 10 seconds.
AIDL, or Android Interface Definition Language, handles the interface requirements between a client and a service so both can communicate at the same level through interprocess communication or IPC. This process involves breaking down objects into primitives that Android can understand. This part is required simply because a process cannot access the memory of the other process.
AIDL has support for the following data types:
A fragment is a part or portion of an activity. It is modular in the sense that you can move around or combine with other fragments in a single activity. Fragments are also reusable.
A visible activity is one that sits behind a foreground dialog. It is actually visible to the user, but not necessarily being in the foreground itself.
The foreground activity, being the most important among the other states, is only killed or terminated as a last resort, especially if it is already consuming too much memory. When a memory paging state has been reaching by a foreground activity, then it is killed so that the user interface can retain its responsiveness to the user.
The career opportunities in the field of Android is dominating the market for years now and as per the data scientists and experts, the momentum will remain consistent or rather increase for the next 10 to 20 years at the same pace when it comes to applying for jobs in this particular sector. As per the surveys are concerned, the salary package for an Android developer begins at 40,000 dollars per annum, while for an experienced candidate, it can go up to 90,000 dollars to 100,000 dollars per annum based on the skills and talent he or she has. Although the salary for the experienced candidates depends on the previous withdrawn salary and the hike they are expecting, the pay scale in this industry is significantly good compared to other sectors.
By reading this article, you will get to know the best Android Interview questions that are commonly asked in an interview. Our professionals ensure to answer all the queries that you have and clear all your doubts within minutes. What you have to do is just drop us a message, and our experts will look into the query and address it immediately.