ANDROID INTERVIEW QUESTIONS
What is Android?
Android is used primarily on mobile devices, such as tablets,mobile and tv. it is an open-sourced operating system that It is a Linux kernel-based system that’s been equipped with rich components that allow developers to create andrun application. Android devices mainly use versions 3.4, 3.10 or 3.18 of the Linux kernel.
What is ADB?
Adb ( Android Debug Bridge).
Adb basic function is to allow and control communication between and from the emulator port. Adb allows developers the power to execute remote shell commands.
What Is Google Android SDK?
Google Android SDK (Software Development Kit)is a toolset that developers need in order to write apps on Android devices.Application are usually developed are usually developed in Java Progeamming language using the Android kit (SDK).
What is Android Architecture?
Android Architecture have 4 key components:
– Linux Kernel
– Android Applications
– Android Framework.
Describe Android Framework ?
Android Framework is an important aspect of Android Architecture.
Here we can find all the classes and methods that developers need in a order to write applications on the Android environment.
What is AAPT?
AAPT-(Android Asset Packaging Tool).
This tool provides ability to developers to deal with zip-compatible archives,
AAPT can also compile resources into binary asserts.
What is an emulator within the Android environment?
Emulators is a safe place for testing codes especially if it is in the early design phase.
Emulator lets developers “play” around an interface that acts like an actual mobile device. Emulators can write and test codes, and even debug.
What is the use of ActivityCreator?
ActivityCreator is a first step towards the creation of new Android project.
It made up of a shell script that will use to create new file system structure necessary to writing codes within the Android IDE.
What is Activities?
An activity represents a single screen for a user interface just like window and frame of Java. Android activity is the subclass of Context Theme Wrapper class.
What are Intents?
Intent is basically a message that is passed between components (such as Activities, Broadcast Receivers, Services, and Content Providers).
So, it is almost equivalent to parameters passed to API calls.
It can be used to alert user of a particular state that occurred.
Who is the founder of Android?
Andy Rubin is the founder of Android.
What important items are in every Android project?
That is present each time an Android project is created:
What is ANR?
ANR ( Application Not Responding). This is actually a dialog box that appears to user whenever an application had been unresponsive to a long period time.
When is onStop() method invoked?
A call to onStop() method happens when activity is no longer visible to user, either because another activity has taken over or if in front of that activity.
Two types of web services are:
What are containers?
Containers may hold buttons, labels, fields, or even child containers, as examples.Containers, as the name itself implies, that holds objects and widgets together, depending on which specific item is needed and in what particular arrangement that is needed.
What is an Orientation?
Orientation, which set for using setOrientation(), dictates if the LinearLayout. be represented as a row or as a column.we use two HORIZONTAL or VERTICAL.
Describe importance of Android in the mobile market?
Developers can write or register apps will specifically run under the Android environment. This means that every mobile device that is Android enabled will able to support and run these apps.With the growing popularity of Android mobile devices, developers can take many advantages of this trend by creating and uploading their apps on the Android Market for distribution of user who wants to download it.
What are disadvantages of Android?
Given that Android is an open-source platform, and the fact is that different Android operating systems have been released on different-different mobile devices, there are no clear cut policy to how applications can adapt with various upgrades and OS versions. One app thats on this particular version of Android Operating System may or may not be runs of another version. Another disadvantage is that since mobile devices such as tablet’s and phones are come in a different sizes and forms, it poses is a challenge for developers to create apps that can be adjust correctly for right screen size and other varying features and specs.
What are the four essential states of an activity?
Active – if activity is at the foreground
Paused – if activity is at the background and still visible
Stopped – if activity is not seen and therefore is hides or obscured by another activity
Destroyed – when the activity process is killed or completed finished.
Which type of elements can occur only once and must be present?
Among the different elements, the and elements must be present and can be occur only once. The rest all are optional, and can occur as many times as wanted.
How escape characters is used as attribute?
Escape characters are preceded by double backslashes(‘ ‘).
For example:-a mewling character created by using ‘\n’
Enumerate the three key loops when monitoring an app activity ?
– Entire lifetime = activity happens to onDestroy and onCreate
– Foreground lifetime = activity happens to onResume and onPause
– Visible lifetime = activity happens to onStart and onStop.
What is the importance of setting permissions in android app development?
Permissions allow certain restrictions imposed primarily to protect code and data. Without these, codes you could be compromised, resulting from defects in functionality of app.