Basic Interview Questions of Android

1) Describe Activities.

An activity is the single screen in android. It is like window or frame of Java.

By the help of activity, you can place all your UI components or widgets in a single screen

2) What are Intents?

Intents displays 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.

Android Intent is the message that is passed between components such as activities, content providers, broadcast receivers, services etc

3) Differentiate Activities from Services.

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.

4) What items are important in every Android project?

These are the essential items that are present each time an Android project is created:

• AndroidManifest.xml
• build.xml
• bin/
• src/
• res/
• assets/

5) What is the importance of XML-based layouts?

The use of XML-based layouts provides a consistent and somewhat standard means of setting GUI definition format. In common practice, layout details are placed in XML files while other items are placed in source files.

6) What are containers?

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.

7) What is Orientation?

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.

8) What is adb?

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.

9) What are the four essential states of an activity?

• Active – if the activity is at the foreground
• Paused – if the activity is at the background and still visible
• Stopped – if the activity is not visible and therefore is hidden or obscured by another activity
• Destroyed – when the activity process is killed or completed terminated

10) What is ANR?

ANR is short for Application Not Responding. This is actually a dialog that appears to the user whenever an application have been unresponsive for a long period of time.