Android is the most common word used in today’s world, the industry of android is vast and the scope of android developer is huge, here are some basic questions about android which can help you give an insight about android and everything about it. Android being the most used operating system in the world with 67% acquisition.
- What is an android ?
Android is an open source which is used in mobiles, tablets and other gadgets, it is used in all the touchscreen devices.It is widely used software which helps developing applications which are cloud-connected. Android is one of the most loved platform due to its adaptability is is preferred by most of the people
- What are features of android architect ?
It refers to different stacks used in android, it includes operating system, middleware and applications, each layer provides different services. The five layers of android stacks are:
- Linux kernel
It manages the core functionality of android such as memory, security, networking and such.
- Libraries
It stores everything that is needed in the development of an application such as source codes, resource files, android manifest. Learning libraries of any code language is not easy if you are a beginner, So try to find an Android Course in Ahmedabad, Mumbai, Pune or wherever you live. Because you will learn more about android development, there are many experts that teach programming languages.
- Android runtime
ART is managed time of an application or software on android. It works along with DVM, it is used to optimize mobile devices, it makes the device run smooth.
- Android framework
It is made of android AIs, like UI, resources data, locations. It offers interfaces and classes to android applications.
- Android applications
Applications like home, settings and contacts etc uses an android framework which then uses android libraries and runtime.
- Languages used to develop android?
There are many languages used in developing android some most common and popular are;
- Java – this is the first language used by most people, and the most commonly used language for building an app.
- Kotlin- Kotlin is the new, modern and the most object oriented cross platform programing languages used to build android
- C# – Developers can create android application by using C# language, visual tool is the best tool for using C# language to develop an app
- Python – it is a popular machine learning language, it is one of the dynamic languages used to develop android applications.
- Other languages- There are many other languages also used to create android like HTML 5. C++C4droid and etc
- What is the life cycle of Android?
- Oncreate () – it is said when activity is created, using this data is stored and created
- Onstart () – It is said when the activity is visible to the user
- onresume() – It is said when activity will start interaction with the user
- onpause() – It is said when the activity is moving in the background
- onstop()- It is said then the activity is no longer visible to the user
- ondestroy()- it is said when the activity is destroyed or finished
- onrestart() – it is said when the activity is stopped before starting .
- Explain the dialog boxes supported in android
Android supports 4 types of dialog box
- Alertdialog
It supports 0-3 buttons, with a list of selectable items like checkboxes and radio button
- Datepickerdialog
It is used to select date by user
- Timepickerdialog
This is used for selecting time by the user
- Progressdialog
This is displayed in the progress bar and is an extension of Alertdialog, it also supports additional buttons
6. What is ANR in Android? What are the measures you can take to avoid ANR?
ANR refers to Application not responding dialog box that occurs when application is not working. This appears on screen when an thread within the application which is unresponsive for a longer period of time for following reasons
- When there is no response in the input for more than 5 seconds
- When broadcast receiver did not reacted with 10 seconds
The measures you can take to avoid ANR are
- The application should perform networking on different threads to avoid ANR.
- For backend task applications, you can lessen the pressure from the User interface thread.
What are containers?
Containers as the name says hold widgets and objects together, depending about what items you need and how you want them organized. They may hold labels, child containers, buttons etc. Android offers many class views that serve as containers, container classes are called layouts.
What is a jobscheduler ?
This API helps schedule various jobs against the framework, which will be executed during your app process, while the job is running, the system locks the screen with wakelock so you don’t have to worry about it turning off while the process is going.
Situations when you can use job scheduler:
- Taks which should be done while the device should be connected to power supply
- Tasks which need wifi or internet connection
- Tasks which should be kept running where timing is not critical.
What is context?
It helps the newly developed to understand what is going on. Basically it helps you understand a part of your own program. It helps you get the information about your surroundings. It gives you access to resources, databases and preferences.
They are two types of context :
- Activity context
This is attached to the activity life cycle, you use it when you need the context whose life cycle is related to your context activity.
- Application context
The application is attached to the lifecycle of application, you use this when the context lifecyle is different than your current context.
10.Mention the difference between class, file and activity in Android?
The difference between Class, file and activity in android is as followed
- Class is a form of .java file that android use to create executable apk files
- A file is resource for storing information , it can be any type of files
- Activity is screen that represents graphical user interface which the user can use to to do something
