Answer the following questions
1. What
are the features of Android?
Ans :
1. Application Framework: It enables
reuse and replacements of components.
2. Dalvik Virtual Machine: It is
optimized for mobile device.
3. Integrated Browser: It is based on open source web kit engine.
4. Handset layouts: Optimized Graphics:
It is powered by a custom 2D graphics Library 3D Graphics based on the OpenGL
ES 1.0 Specification.
5. Storage: SQLite, a lightweight
relational database.
6. Media Support: Android supports the
following audio/video/still media formats: H.263, H.264 (in 3GP or MP4
container), MPEG 4 SP, AMR, AMR WB (in 3GP container), AAC, HE AAC (in MP4 or
3GP container), MP3, MIDI, Ogg Vorbis, WAV, JPEG, PNG, GIF, BMP
7. Connectivity: GSM/EDGE, IDEN, CDMA,
EVDO, UMTS, Bluetooth, WiFi.
8. Messaging: SMS and MMS are available
forms of messaging, also support Android Cloud to Device Messaging
Framework (C2DM).
9. Multiple Language Support: Multiple
Languages Available in Android.
10. Additional hardware support:
Android can use video/still cameras, touch screens, GPS, accelerometers,
gyroscopes, magnetometers.
2. Explain
the Android stack diagrammatically/ Android architecture.
Ans :
Linux kernel: This is the kernel on
which Android is based. This layer contains all the low level device drivers
for the various hardware components of an Android device.
Libraries: These contain all the code
that provides the main features of an Android OS. For example, the SQLite library
provides database support so that an application can use it for data storage.
The Webkit library provides functionalities for web browsing.
Android runtime: At the same layer as
the libraries, the Android provides a set of core libraries that enable
developers to write Android apps using the Java programming language.
Application framework: Exposes the
various capabilities of the Android OS to application developers so that they
can make use of them in their applications.
3. Explain
SDK platform in deatil.
Ans :
The Android SDK (Software Development
Kit) is the most important software of android which is installed. The Android
SDK provides to test android applications, the API libraries, an emulator,
documentation, sample code, developer tools and tutorials which help you to
build, test and debug apps of Android SDK contains Debugger Libraries
Emulator Documentation Sample Code Tutorials Android SDK is made up of two main
parts: the tools and the packages. When you first install the SDK, all you
obtain are the base tools. Is helps you to develop applications. The packages
are the records specific to a particular version of Android.
4. What
is activity?
Ans :
An activity is a window that contains
the user interface of your applications. An application can have zero or more
activities. Typically, applications have one or more activities, and the main
aim of an activity is to interact with the user. From the moment an activity
appears on the screen to the moment it is hidden, it goes through a number of
stages, known as an activity's life cycle. Understanding the life cycle of an
activity is vital to ensuring that your application works correctly.
5. What
is intent?
Ans :
The Android operating system uses an
asynchronous messaging mechanism to match task requests with the appropriate
Activity. Each request is packaged as an Intent The intent generally consists
of activities to be done, the parameter over which this activity is to be
performed, and the application to perform this action. Examples of processes
defined as intents:
1. Start of certain activities.
2. Displaying a web page.
3. Answering a call.
4. Dialing a number.
6. With
the help of diagram describe activity life cycle.
Ans :
Method Description
onCreate called when activity is first created.
onStart called
when activity is becoming visible to the user.
onResume called when activity will start interacting with the user.
onPause called
when activity is not visible to the user.
onStop called
when activity is no longer visible to the user.
onRestart called after your activity is stopped, prior to start.
onDestroy called before the activity is destroyed.
7. Describe
lifecycle of fragment diagrammatically.
Ans :
In Android, the fragment is the part of
Activity which represents a portion of User Interface(UI) on the screen. It is
the modular section of the android activity that is very helpful in creating UI
designs that are flexible in nature and auto-adjustable based on the device
screen size. The UI flexibility on all devices improves the user experience and
adaptability of the application. Fragments can exist only inside an activity as
its lifecycle is dependent on the lifecycle of host activity. For example, if
the host activity is paused, then all the methods and operations of the
fragment related to that activity will stop functioning, thus fragment is also
termed as sub-activity.
8. Enlist
type of intents.
Ans :
Explicit Intent − It going to connect
the internal world of an application such as start activity or send data
between two activities.
Implicit Intents − It going to connect
with out side application such as call, mail, phone,see any website ..etc.
9. How
to calling built-in applications using intents? Explain using example
Ans :
Calling built in applications using
intents in Android is important as it give user more choices. For example in an
app you want user make a call or open a document (pdf) let you use the in-build
apps, take off the burden in developing those apps.
Android intent example
Lets get started with how to use intent
in android. The following Try It Out demonstrates how to call some of the
built-in applications commonly found on an Android device.
Creating New Project
1. First step : Open Android Studio and
Create a new project by selecting 'Start a new Android Studio Project'. Give it
a name MyIntent and a package name in.ruks. You can have your own application
package names. Click next, choose minimum SDK, in ours case it is API 14.
Android Studio will create the the new Android Project with all the necessary
files.
Set up Project Layout
We are going to use 6 built-in
application in this example. They are -
1. Gallery 2. Call Log 3. Contact 4.
Dailler 5. Browser 6. Map
2. Second step : Now the time to set up
the layout of our project. We are going to call 6 built-in applications using
intents, hence we will place a button for each in activity_main.xml. You can
drag and drop 6 button on the layout or simply create by coding the
activity_main.xml file.
3. Third step : It's bad idea to have
the hard coded string in the project. So in this android intent example code,
we are given name to each of the button within the strings.xml, which is under
the values folder in Android Studio. Add the code below in it -
Creating event handler
4. Fourth step : In our
MainActivity.java file, we are going to declare the button for each of the
Button we have created in our layout file.
5. Fifth step : Our Buttons are ready
to have some action, now its time to attach the event handler to them. One by
one we are going to call setOnClickListener method on each of our Button and
call built-in applications.
Declare Activity in AndroidManifest
6. Final step : If you have basic
knowledge of developing android apps then you must know that, every activity
you have in your application must be declared in your AndroidManifest.xml file.
10. What
is UI?
Ans :
The user interface (UI) for an Android
app is built as a hierarchy of layouts and widgets. The layouts are ViewGroup
objects, containers that control how their child views are positioned on the
screen. Widgets are View objects, UI components such as buttons and text boxes.
11. What
is layout? Enlist Layout Managers.
Ans :
A layout defines the structure for a
user interface in your app, such as in an activity. All elements in the layout
are built using a hierarchy of View and ViewGroup objects. A View usually draws
something the user can see and interact with. Whereas a ViewGroup is an
invisible container that defines the layout structure for View and other
ViewGroup objects
layout Manager
1. A LinearLayout lines up its views in
one row or column.
2. A FrameLayout is a simple layout
manager used to display one view.
3. A RelativeLayout is a layout manager
in which the views are positioned in relation to each other or to the parent.
12. What
is view?
Ans :
View is a basic building block of UI
(User Interface) in android. A view is a small rectangular box that responds to
user inputs. Eg: EditText, Button, CheckBox, etc. ViewGroup is an invisible
container of other views (child views) and other ViewGroup.
13. What
is Action bar?
Ans :
The app bar, also known as the action
bar, is one of the most important design elements in your app's activities,
because it provides a visual structure and interactive elements that are
familiar to users.
14. Describe
the following LayoutManagers with example:
Ans :
a. LinearLayout
Linear layout is a simple layout used
in android for layout designing. In the Linear layout all the elements are
displayed in linear fashion means all the childs/elements of a linear layout
are displayed according to its orientation. The value for orientation property
can be either horizontal or vertical.
There are two types of linear layout
orientation:
1. Vertical
2. Horizontal
b. Tablelayout
A layout that arranges its children
into rows and columns. A TableLayout consists of a number of TableRow objects,
each defining a row (actually, you can have other children, which will be
explained below). TableLayout containers do not display border lines for their
rows, columns, or cells. Each row has zero or more cells; each cell can hold
one View object. The table has as many columns as the row with the most cells.
A table can leave cells empty. Cells can span columns, as they can in HTML.
15. Explain
the term utilizing action bar in detail.
Ans :
Action Bar is one of the important
parts of any application, whether it’s a web application or a mobile app. Today
we will learn how to implement an action bar in android apps using the
ActionBar component.
Android ActionBar is a menu bar that
runs across the top of the activity screen in android. Android ActionBar can
contain menu items which become visible when the user clicks the “menu” button.
In general an ActionBar consists of the
following four components:
App Icon: App branding logo or icon
will be displayed here
View Control: A dedicated space to
display Application title. Also provides option to switch between views by
adding spinner or tabbed navigation
Action Buttons: Some important actions
of the app can be added here
Action Overflow: All unimportant action
will be shown as a menu
16. What
is ScrollView? Explain with example.
Ans :
a ScrollView is a view group that is
used to make vertically scrollable views. A scroll view contains a single
direct child only. In order to place multiple views in the scroll view, one
needs to make a view group(like LinearLayout) as a direct child and then we can
define many views inside it. A ScrollView supports Vertical scrolling only, so
in order to create a horizontally scrollable view, HorizontalScrollView is
used.
17. With
the help of diagram describe FrameLayout
Ans :
Frame Layout is one of the simplest
layout to organize view controls. They are designed to block an area on the
screen. Frame Layout should be used to hold child view, because it can be
difficult to display single views at a specific area on the screen without
overlapping each other.
We can add multiple children to a
FrameLayout and control their position by assigning gravity to each child,
using the android:layout_gravity attribute.
18. What
is the TextView?
Ans :
A TextView displays text to the user and
optionally allows them to edit it. A TextView is a complete text editor,
however the basic class is configured to not allow editing.
19. With
the help of example explain RadioButton.
Ans :
RadioButton is a two states button
which is either checked or unchecked. If a single radio button is unchecked, we
can click it to make checked radio button. Once a radio button is checked, it
cannot be marked as unchecked by user.
RadioButton is generally used with
RadioGroup. RadioGroup contains several radio buttons, marking one radio button
as checked makes all other radio buttons as unchecked.
20. What
is meant by button? Describe with example.
Ans :
In Android applications, a Button is a
user interface that is used to perform some action when clicked or tapped. It
is a very common widget in Android and developers often use it.
21. What
is the EditText?
Ans :
A EditText is an overlay over TextView
that configures itself to be editable. It is the predefined subclass of
TextView that includes rich editing capabilities.
22. Explain
the AutoCompleteTextView in detail.
Ans :
A AutoCompleteTextView is a view
that is similar to EditText, except that it shows a list of completion
suggestions automatically while the user is typing.
The AutoCompleteTextView is a type of
edit text in android which gives suggestions to the user if the user types
something in the AutoCompleteTextView. This type of edit text we can see while
we register on some websites. If we type “In” it will suggest India, Indonesia,
West Indies ….. etc. Like this, the AutoCompleteTextView works. Let us see the
implementation of AutoCompleteTextView in XML and Java . Here XML is used to
create the layout and java code is used to implement the main function of
AutoCompleteTextView .
23. Write
short note on: ProgressBar.
Ans :
A progress bar is a graphical control element
used to visualize the progression of an extended computer operation, such as a
download, file transfer, or installation. Sometimes, the graphic is accompanied
by a textual representation of the progress in a percent format.
24. What
is ToggleButton? How to create it? Explain with example.
Ans :
Android Toggle Button can be used to
display checked/unchecked (On/Off) state on the button.
It is beneficial if user have to change
the setting between two states. It can be used to On/Off Sound, Wifi, Bluetooth
etc.
Since Android 4.0, there is another
type of toggle button called switch that provides slider control.
Android ToggleButton and Switch both
are the subclasses of CompoundButton class.
<?xml version="1.0"
encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="example.javatpoint.com.togglebutton.MainActivity">
<ToggleButton
android:id="@+id/toggleButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="8dp"
android:layout_marginTop="80dp"
android:text="ToggleButton"
android:textOff="Off"
android:textOn="On"
app:layout_constraintEnd_toStartOf="@+id/toggleButton2"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
25. Describe
the following terms:
Ans :
a. DatePicker
: Android Date Picker allows you to select the date consisting of day, month
and year in your custom user interface. For this functionality android provides
DatePicker and DatePickerDialog components.
b. TimePicker
: Android Time Picker allows you to select the time of day in either 24 hour or
AM/PM mode. The time consists of hours, minutes and clock format. Android
provides this functionality through TimePicker class.
26. What
is the gallery in Android?
Ans :
Gallery is an offline photo gallery.
You can use it to edit, find, and manage photos without being connected to the
Internet. Gallery also works with SD cards on Android devices. Tip: Gallery is
available on Android devices.
27. What
is GridView in Android?
Ans :
A GridView is a type of AdapterView
that displays items in a two-dimensional scrolling grid. Items are inserted
into this grid layout from a database or from an array. The adapter is used for
displaying this data, setAdapter() method is used to join the adapter with
GridView. The main function of the adapter in GridView is to fetch data from a
database or array and insert each piece of data in an appropriate item that
will be displayed in GridView.
28. What
is ImageView in Android?
Ans :
ImageView class is used to display any
kind of image resource in the android application either it can be
android.graphics.Bitmap or android.graphics.drawable.Drawable (it is a general
abstraction for anything that can be drawn in Android). ImageView class or
android.widget.ImageView inherits the android.view.View class which is the
subclass of Kotlin.Any class. Application of ImageView is also in applying
tints to an image in order to reuse a drawable resource and create overlays on
background images.
29. Write
short note on: Creating the helper methods.
Ans :
1. Provides common methods which are
required by multiple classes in the project.
2. Helper methods are generally public
and static so that these can be invoked independently.
3. Each methods of a helper class
should work independent of other methods of same class.
30. What
is menu? Enlist its types.
Ans :
The traditional menu definition is a
list of food or drink items available for purchase, or a list of food or drink
items that will be served. That can be a seasonal menu, a fixed menu, or
something in between. While the majority of the time the meaning of menu is
applied to food and beverages, that’s not always the case.
The word menu is also used frequently
in the context of electronic devices and computer programs. There it usually
refers to a navigable list of options a user can interact with.
The five types of menus most commonly
used are 1. a la carte menus, 2. static menus, 3. du jour menus, 3. cycle
menus, and 3. fixed menus.
31. What
is thread?
Ans :
A thread is a thread of execution in a
program. The Java Virtual Machine allows an application to have multiple
threads of execution running concurrently. Every thread has a priority. Threads
with higher priority are executed in preference to threads with lower priority.
32. Enlist
Types of handlers.
Ans :
Runnable, long) , postDelayed(Runnable,
Object, long) , sendEmptyMessage(int) , sendMessage(Message) ,
sendMessageAtTime(Message, long) , and sendMessageDelayed(Message, long)
33. What
is SMS?
Ans :
We’re all familiar with SMS, or
standard text messages. After all, it’s one of the oldest and most commonly
used methods of mobile communication. While SMS is seemingly humdrum in the
modern age, there’s a surprising amount of coordination and technology working
in the background to send such seemingly simple messages. So let’s take a look
at how it all works.
35. What
is Broadcast Receiver?
Ans :
A broadcast receiver (receiver) is an
Android component which allows you to register for system or application
events. All registered receivers for an event are notified by the Android
runtime once this event happens.
36. What
is meant by database?
SQLite Database is an open-source
database provided in Android which is used to store data inside the user's
device in the form of a Text file. We can perform so many operations on this
data such as adding new data, updating, reading, and deleting this data.
37. What
is SQLite?
SQLite is a C-language library that
implements a small, fast, self-contained, high-reliability, full-featured, SQL
database engine. SQLite is the most used database engine in the world. SQLite
is built into all mobile phones and most computers and comes bundled inside
countless other applications that people use every day.
38. Enlist
feature of SQLite.
1. Transactions are atomic, consistent,
isolated, and durable (ACID) even after system crashes and power failures.
2. Zero-configuration - no setup or
administration needed.
3. Full-featured SQL implementation
with advanced capabilities like partial indexes, indexes on expressions, JSON,
common table expressions, and window functions. (Omitted features)
4. A complete database is stored in a
single cross-platform disk file. Great for use as an application file format.
5. Supports terabyte-sized databases
and gigabyte-sized strings and blobs. (See limits.html.)
6. Small code footprint: less than
750KiB fully configured or much less with optional features omitted.
7. Simple, easy to use API.
8. Fast: In some cases, SQLite is
faster than direct filesystem I/O
9. Written in ANSI-C. TCL bindings
included. Bindings for dozens of other languages available separately.
10. Well-commented source code with
100% branch test coverage.
11. Available as a single ANSI-C
source-code file that is easy to compile and hence is easy to add into a larger
project.
12. Self-contained: no external
dependencies.
39. How
to close database using SQLite?
close( conn ) closes the SQLite
connection by using the MATLAB® interface to SQLite. The SQLite connection
object remains open until you close it using the close function. Always close
this object when you finish using it.
40. What
is meant by Google map?
Google Maps is a Web-based service that
provides detailed information about geographical regions and sites around the
world. In addition to conventional road maps, Google Maps offers aerial and
satellite views of many places. In some cities, Google Maps offers street views
comprising photographs taken from vehicles.
41. How
to create Google map?
1. On your computer, sign in to My
Maps.
2. Click Create a new map.
3. Go to the top left and click
"Untitled map."
4. Give your map a name and
description.
42. What
is marker? How to add markers in Google map.
Markers are objects of type Marker ,
and are added to the map with the GoogleMap. addMarker(markerOptions) method.
Markers are designed to be interactive. They receive click events by default,
and are often used with event listeners to bring up info windows.
How to Add :
1. On your computer, sign in to My
Maps.
2. Open or create a map. A map can have
up to 10,000 lines, shapes, or places.
3. Click Add marker .
4. Select a layer and click where to
put the place. A layer can have 2,000 lines, shapes, or places.
5. Give your place a name.
6. Click Save
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