android populer

What is the importance of having an emulator within the Android environment?
The emulator provides an interface that acts as if it were an actual mobile device. They can write and test codes, and even debug. Emulators are a safe place for testing codes especially if it is in the early design phase.

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.

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.

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.

What is the importance of Android in the mobile market?
Developers can write and register apps that will specifically run under the Android environment. This means that every mobile device that is Android enabled will be able to support and run these apps. With the growing popularity of Android mobile devices, developers can take advantage of this trend by creating and uploading their apps on the Android Market for distribution to anyone who wants to download it.

What do you think are some disadvantages of Android?
Given that Android is an open-source platform, and the fact that different Android operating systems have been released on different mobile devices, there’s no clear cut policy to how applications can adapt with various OS versions and upgrades. One app that runs on this particular version of Android OS may or may not run on another version. Another disadvantage is that since mobile devices such as  phones and tabs come in different sizes and forms, it poses a challenge for developers to create apps that can adjust correctly to the
right screen size and other varying features and specs.

How will you record a phone call in Android? How to get a handle on Audio Stream for a call in Android?
Permissions.PROCESS_OUTGOING_CALLS: Allows an application to monitor, modify, or abort outgoing calls.

How are escape characters used as attribute?
Escape characters are preceded by double backslashes. For example, a newline character is created using ‘\\n’

What are the different states wherein a process is based?
There are 4 possible states:
- foreground activity
- visible activity
- background activity
- empty process

When does ANR occur?
The ANR dialog is displayed to the user based on two possible conditions. One is when there is no response to an input event within
5 seconds, and the other is when a broadcast receiver is not done executing within 10 seconds.

public class MainActivity extends Activity {
}

What is services ?
              A service is a component that runs in the background to perform long-running operations or to perform work for remote processes. A service does not provide a user interface.For example : Running an alarm in background
A service is implemented as a subclass of Service.

What are Content Providers ?
             They manages a shared set of application data.Data can be stored in SQLite Database,File systems,web or any other medium where application can access.
Content Providers allows to modify and use these stored data.For example : storing users contacts details,where proper permission one can get the contacts.
A content provider is implemented as a subclass of ContentProvider.

What are Broadcast receivers ?
          They responds to systems  broadcast announcements.Some of the native Broadcast are volume control, light, switch on and off, screen on and off,bluetooth etc.A broadcast receiver is just a "gateway" to other components and is intended to do a very minimal amount of work. For instance, it might initiate a service to perform some work based on the event. 
A broadcast receiver is implemented as a subclass of BroadcastReceiver.

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.

What is definition of Android ?
               Android is a software stack for mobile devices that middleware, operating systems,
   and application-specific key. The application must be implemented in its own process
   and the Dalvik virtual machine interface. DVM is used effectively run multiple virtual
   machines. Java byte code is executed which is converted file format called Dex.

How the data will be stored in Android or types of data stored in Android ?

•   Internal Storage
•   Connecting to a network 
•   General preferences 
•   SQLite database
•   External Storage

 See more basics on Android 

All the components are activated by a message called Intents. Intents bind individual components to each other at runtime, whether the component belongs to your application or another. An intent is created with an Intent object, which defines a message to activate either a specific component or a specific type of component—an intent can be either explicit or implicit, respectively.
An intent is an abstract description of an operation to be performed. Intents are send to the Android system via a method call, e.g. via the startActivity() method. They can be said as a message which allow android components to request functionality from other components.

Intent Filters:Activities and intent receivers include one or more filters in their manifest to describe what kinds of intents or message they can handle or want to receive.An intent filters lists a set of requirements, such as datatypes,action requested and URI format that the intent or message must fulfil.

Types Of Intents:
Implicit Intents :
Implicit Intents have not specified a component; instead, they must include enough information for the system to determine which of the available components is best to run for that intent.

Button browserview= (Button)findViewById(R.id.bview);
browserview.setOnClickListener(new OnClickListener() {
 public void onClick(View v) {
   Intent browserintent = new Intent(Intent.ACTION_VIEW, Uri.pars("http://www.http://eazyprogramming.blogspot.in/"));
   startActivity(browserintent);
}
});

Explicit Intent:
Explicit Intents have specified a component, which provides the exact class to be run. Often these will not include any other information, simply being a way for an application to launch various internal activities it has as the user interacts with the application.

Button openclass= (Button)findViewById(R.id.bopenclass);
openclass.setOnClickListener(new OnClickListener() {
 public void onClick(View v) {
   Intent openintent = new Intent(FirstActivity.this,SecondActivity.class));
   startActivity(openintent);
}
});

public class MainActivity extends Activity {
}

Services :
          A service is a component that runs in the background to perform long-running operations or to perform work for remote processes. A service does not provide a user interface.For example : Running an alarm in background
A service is implemented as a subclass of Service.

Content providers :
          They manages a shared set of application data.Data can be stored in SQLite Database,File systems,web or any other medium where application can access.
Content Providers allows to modify and use these stored data.For example : storing users contacts details,where proper permission one can get the contacts.
A content provider is implemented as a subclass of ContentProvider.

Broadcast receivers :
          They responds to systems  broadcast announcements.Some of the native Broadcast are volume control, light, switch on and off, screen on and off,bluetooth etc.A broadcast receiver is just a "gateway" to other components and is intended to do a very minimal amount of work. For instance, it might initiate a service to perform some work based on the event.
A broadcast receiver is implemented as a subclass of BroadcastReceiver.

Who Activates A component ?
         The above components are activated by a message called Intents.
Intents bind individual components to each other at runtime, whether the component belongs to your application or another.
An intent is created with an Intent object, which defines a message to activate either a specific component or a specific type of component—an intent can be either explicit or implicit, respectively.

         The Content Provider, is not activated by intents. It is activated when there is request from ContentResolver. These Resolvers handles direct transaction with the providers so they donot need further any method calls. This leaves a layer of abstraction between the content provider and the component requesting information (for security).

What is an AndroidManifest file ?
          This is a root directory of Android application where all the components are declared.Other than this they also have

• user permissions the application requires, such as read and write external storage
• Declare the minimum API level
• Declare hardware and software features such as bluetooth or a printer
• API libraries etc...

 

Sometimes we may need to include a long default text on a single line in EditText, for that we can set the EditText to single line and provide a horizontal scroll.

 <EditText
            android:id="@+id/EditTextValue"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:singleLine="true"
            android:scrollHorizontally="true"
            android:text="This is a big text to be included in the edittext so added a horizontal scroll..."/ >