Android is a stack of software for mobile devices which has Operating System, middleware and some key applications. The application executes within its own process and its own instance of Dalvik Virtual Machine. Many Virtual Machines run efficiently by a DVM device. DVM executes Java language's byte code which later transforms into .dex format files.
2. Explain android activities?
Activity provides the user interface. When you create an android application in eclipse through the wizard it asks you the name of the activity. Default name is MainActivity. You can provide any name according to the need. Basically it is a class (MainActivity) that is inherited automatically from Activity class. Mostly, applications have oneor more activities; and the main purpose of an activity is to interact with the user. Activity goes through a numberof stages, known as an activity's life cycle.
3. What are the differences between a domain and a workgroup?
In a domain, one or more computer can be a server to manage the network. On the other hand in a workgroup all computers are peers having no control on each other. In a domain, user doesn't need an account to logon on a specific computer if an account is available on the domain. In a work group user needs to have an account for every computer.
In a domain, Computers can be on different local networks. In a work group all computers needs to be a part of the same local network.
4. How much dialog boxes are supported in android?
Android supports 4 dialog boxes:
★ AlertDialog
★ ProgressDialog
★ DatePickerDialog
★ TimePickerDialog
5. List important file and folder when you create new android application?
When we create android application the following folders are created in the package explorer in eclipse which are as follows:
★ src
★ gen
★ assets
★ bin
★ res
6. Explain the sending SMS in android?
SMS messaging is one of the basic and important applications on a mobile phone. Now days every mobile phone has SMS messaging capabilities, and nearly all users of any age know how to send and receive such messages. Mobile phones come with a built-in SMS application that enables you to send and receive SMS messages.
7. Explain how to use built-in messaging within the application?
Intent object to activate the built-in Messaging service. You have to pass MIME type "vnd.android-dir/mms-sms", in setType method of Intent as shown in the following given below code.
Intent intent = new Intent (android.content.Intent.ACTION_VIEW);
intent.putExtra("address", "5556; 5558;");// Send the message to multiple recipient.
itent.putExtra("sms_body", "Hello my friends!");
intent.setType("vnd.android-dir/mms-sms");
startActivity(intent);
8. Explain sending SMS messages programmatically?
Take a button on activity_main.xml file as follows.
<Button android:id="@+id/btnSendSMS" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerHorizontal="true" android:layout_centerVertical="true" android:onClick="sendmySMS" android:text="sendSMS" />
According to above code when user clicks the button sendmySMS method will be called. sendmySMS is user defined method.
In the AndroidManifest.xml file, add the following statements
<uses-permissionandroid:name="android.permission.SEND_SMS"/>
Now we write the final step. Write the given below method in MainActivity,java file
publicvoidsendmySMS(View v)
{
SmsManagersms = SmsManager.getDefault();
sms.sendTextMessage("5556", null, "Hello from google", null, null);
}
In this example I have used two emulator. On the first Android emulator (5554), click the Send SMSbutton to send an SMS message to the second emulator(5556).
9. Explain activity creator in Android?
★ An activity Creator is the initial step for creation of a new Android project.
★ It consists of a shell script that is used to create new file system structure required for writing codes in Android IDE.
10. Explain Dalvik Virtual Machine?
★ It is Android's virtual machine.
★ It is an interpreter-only virtual machine which executes files in Dalvik Executable (.dex) format. This format is optimized for efficient storage and memory-mappable execution.
11. What data types are supported by AIDL?
AIDL supports following data types:
★ String
★ List
★ Map
★ CharSequence
★ All native Java data types like int,long, char and Boolean
★ AIDL is the abbreviation for Android Interface Definition Language.
★ It handles the interface requirements between a client and a service to communicate at the same level through inter-process communication.
★ The process involves breaking down objects into primitives that are Android understandable.
13. Explain key components of Android Architecture?
Android Architecture consists of 4 key components:
★ Linux Kernel
★ Libraries
★ Android Framework
★ Android Applications
14. Explain application of shared preference?
★ Storing the information about number of visitors (counter).
★ Storing the date and time (when your Application is updated).
★ Storing the username and password.
Storing the user settings.
Different data storage options are available in Android are:
★ SharedPreferences
★ SQlite
★ ContentProvider
★ File Storage
★ Cloud Storage
16. Which kind of information about the application AndroidManifest.xml file contains?
★ It contains the package name of the application.
★ The version code of the application is 1.This value is used to identify the version number of your application.
★ The version name of the application is 1.0
★ The android:minSdkVersion attribute of the element defines the minimum version of the OS on which the application will run.
★ ic_launcher.png is the default image that located in the drawable folders.
★ app_name defines the name of applicationand available in the strings.xml file.
★ It also contains the information about the activity. Its name is same as the application name.
17. Explain AndroidManifest.xmlfile in detail?
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.globalguideline" android:versionCode="1" android:versionName="1.0">
<uses-sdk android:minSdkVersion="8" android:targetSdkVersion="18" />
<application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme">
<activity android:name="com.example.globalguideline.MainActivity" android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
18. Explain src file in Android?
src Contains the .java source files for your project. You write the code for your application in this file. This file is available under the package name for your project.
19. Explain bin file in Android?
It contains the .apk file (Android Package) that is generated by the ADT during the build process. An .apk file is the application binary file. It contains everything needed to run an Android application.
20. Explain assets folder in Android?
This folder contains all the information about HTML file, text files, databases, etc.
21. Explain Android 4.0 library folder in Android?
This folder contains android.jar file, which contains all the class libraries needed for an Android application.
22. Explain gen folder in Android?
This folder contains the R.java file. It is compiler-generated file that references all the resources found in your project. You should not modify this file.
23. Explain res folder in Android?
This folder contains all the resource file that is used byandroid application. It contains subfolders as: drawable, menu, layout, and values etc.
24. Explain AlertDialog in Android?
An alert dialog box supports 0 to 3 buttons and a list of select-able elements, including check boxes and radio buttons. Among the other dialog boxes, the most suggested dialog box is the alert dialog box.
25. Explain ProgressDialog in Android?
This dialog box displays a progress wheel or a progress bar. It is an extension of AlertDialog and supports adding buttons.
26. Explain DatePickerDialog in Android?
This dialog box is used for selecting a date by the user.
27. Explain TimePickerDialog in Android?
This dialog box is used for selecting time by the user.
28. How to translate in Android?
The Google translator translates the data of one language into another language by using XMPP to transmit data. You can type the message in English and select the language which is understood by the citizens of the country in order to reach the message to the citizens.
29. Please explain the difference between nine-patch image vs regular Bitmap image?
It is one of a re-sizable bitmap resource which is being used as backgrounds or other images on the device. The Nine-Patch class allows drawing a bitmap in nine sections. The four corners are un-scaled; the middle of the image is scaled in both axes, the four edges are scaled into one axis.
30. What is needed to make multiple choice list with custom view for each row?
Multiple choice list can be viewed by making the CheckBox android:id value be "@android:id /text1″. That is the ID used by Android for the CheckedTextView in simple_list_item_multiple_choice.
31. Explain APK format for Android?
The APK file is compressed AndroidManifest.xml file with extension .apk. It also includes the application code (.dex files), resource files, and other files which are compressed into a single .apk file.
32. How to handle an audio stream for call in Android?
Permission.PROCESS_OUTGOING_CALLS: Will Allow an application to monitor, modify, or abort outgoing calls. So using that permission we can monitor the Phone calls.
35. Explain resource in Android?
A user defined JSON, XML, bitmap, or other file, injected into the application build process, which can later be loaded from code.
