What is Android?
Android is a software stack for mobile devices that includes an operating system, middleware and key applications.
Android is a software stack for mobile devices that includes an operating system, middleware and key applications.
Explain the Architecture of android ?
Top -> Applications (Contacts, Browser, Phone, etc)
Below Applications -> Application Framework(Activity Manager, Window Manager, Content Providers, View System, Package manager,
Telephony manager, Resource, Notification, Location managers)
Below Application Framework -> System Libraries(Like Sqlite, webkit, SSL, OpenGL, Media Framework etc) & Android Runtime( Core Libraries and DVM)
Atlast Last -> Linux Kernel (which composed of drivers like display, camera etc.)
Describe the APK format.
The APK file is compressed the AndroidManifest.xml file, application code (.dex files), resource files, and other files.
A project is compiled into a single .apk file.
What is an action?
A description of something that an Intent sender desires.
What is an activity?
A single screen in an application, with supporting Java code.
An activity presents a visual user interface for one focused endeavor the user can undertake.
For example, an activity might present a list of menu items users can choose from or it might display photographs along with their captions.
Each one is implemented as a subclass of the Activity base class.
What is a service?
A service doesn’t have a visual user interface, but rather runs in the background for an indefinite period of time.
For example, a service might play background music as the user attends to other matters, or it might fetch data over the network or calculate
something and provide the result to activities that need it.
Each service extends the Service base class.
What is a Broadcast receivers?
A broadcast receiver is a component that does nothing but receive and react to broadcast announcements.
For example, announcements that the timezone has changed, that the battery is low or that the user changed a language preference.
All receivers extend the BroadcastReceiver base class.
Broadcast receivers do not display a user interface. However, they may start an activity in response to the information they receive,
or they may use the NotificationManager to alert the user like(flashing the backlight, vibrating the device, playing a sound)
What is a content provider?
A content provider makes a specific set of the application’s data available to other applications.The content provider extends the ContentProvider
base class to implement a standard set of methods that enable other applications to retrieve and store data of the type it controls.
However, applications do not call these methods directly. Rather they use a ContentResolver object and call its methods instead.
What is intent?
A class (Intent) describes what a caller desires to do. The caller sends this intent to Android’s intent resolver, which finds the most suitable activity for the intent.
How is nine-patch image different from a regular bitmap?
It is a resizable bitmap resource that can be used for backgrounds or other images on the device. The NinePatch class permits drawing a bitmap in nine sections. The four corners are unscaled; the four edges are scaled in one axis, and the middle is scaled in both axes.
What languages does Android support for application development?
Android applications are written using the Java programming language.
What is a resource?
A user-supplied XML, bitmap, or other file, injected into the application build process, which can later be loaded from code.
What Virtual Machine Android runs on?
Dalvik virtual machine
Android Latest Version?
Android 3.0
How do you define the user interface?
XML Format is the best.
Code Snippets:
————————
How to start a browser instance with some url ?
//Function called when return from a sub activity.
//How to retrieve the device IMEI Number
How to call a subactivity?
Top -> Applications (Contacts, Browser, Phone, etc)
Below Applications -> Application Framework(Activity Manager, Window Manager, Content Providers, View System, Package manager,
Telephony manager, Resource, Notification, Location managers)
Below Application Framework -> System Libraries(Like Sqlite, webkit, SSL, OpenGL, Media Framework etc) & Android Runtime( Core Libraries and DVM)
Atlast Last -> Linux Kernel (which composed of drivers like display, camera etc.)
Describe the APK format.
The APK file is compressed the AndroidManifest.xml file, application code (.dex files), resource files, and other files.
A project is compiled into a single .apk file.
What is an action?
A description of something that an Intent sender desires.
What is an activity?
A single screen in an application, with supporting Java code.
An activity presents a visual user interface for one focused endeavor the user can undertake.
For example, an activity might present a list of menu items users can choose from or it might display photographs along with their captions.
Each one is implemented as a subclass of the Activity base class.
What is a service?
A service doesn’t have a visual user interface, but rather runs in the background for an indefinite period of time.
For example, a service might play background music as the user attends to other matters, or it might fetch data over the network or calculate
something and provide the result to activities that need it.
Each service extends the Service base class.
What is a Broadcast receivers?
A broadcast receiver is a component that does nothing but receive and react to broadcast announcements.
For example, announcements that the timezone has changed, that the battery is low or that the user changed a language preference.
All receivers extend the BroadcastReceiver base class.
Broadcast receivers do not display a user interface. However, they may start an activity in response to the information they receive,
or they may use the NotificationManager to alert the user like(flashing the backlight, vibrating the device, playing a sound)
What is a content provider?
A content provider makes a specific set of the application’s data available to other applications.The content provider extends the ContentProvider
base class to implement a standard set of methods that enable other applications to retrieve and store data of the type it controls.
However, applications do not call these methods directly. Rather they use a ContentResolver object and call its methods instead.
What is intent?
A class (Intent) describes what a caller desires to do. The caller sends this intent to Android’s intent resolver, which finds the most suitable activity for the intent.
How is nine-patch image different from a regular bitmap?
It is a resizable bitmap resource that can be used for backgrounds or other images on the device. The NinePatch class permits drawing a bitmap in nine sections. The four corners are unscaled; the four edges are scaled in one axis, and the middle is scaled in both axes.
What languages does Android support for application development?
Android applications are written using the Java programming language.
What is a resource?
A user-supplied XML, bitmap, or other file, injected into the application build process, which can later be loaded from code.
What Virtual Machine Android runs on?
Dalvik virtual machine
Android Latest Version?
Android 3.0
How do you define the user interface?
XML Format is the best.
Code Snippets:
————————
How to start a browser instance with some url ?
1 | Intent intent = new Intent(Intent.ACTION_VIEW); |
2 | Uri u = Uri.parse("http://google.com"); |
3 | intent.setData(u); |
4 | startActivity(intent); |
1 | protected void onActivityResult(int requestCode, int resultCode, String data, Bundle extras) { |
2 | } |
1 | TelephonyManager mTelephonyMgr = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE); |
2 | imei = mTelephonyMgr.getDeviceId(); |
How to call a subactivity?
1 | Intent intent = new Intent(this, SubActivity.class); |
2 | //to pass data |
3 | addintent.putExtra(name, value); |
4 | startActivityForResult(intent, int); |
What is an action?
A description of something that an Intent sender desires.
What is activity?
A single screen in an application, with supporting Java code.
What is intent?
A class (Intent) describes what a caller desires to do. The caller sends this intent to Android's intent resolver, which finds the most suitable activity for the intent. E.g. opening a PDF file is an intent, and the Adobe Reader is the suitable activity for this intent.
How is nine-patch image different from a regular bitmap?
It is a resizable bitmap resource that can be used for backgrounds or other images on the device. The NinePatch class permits drawing a bitmap in nine sections. The four corners are unscaled; the four edges are scaled in one axis, and the middle is scaled in both axes.
What languages does Android support for application development?
Android applications are written using the Java programming language.
What is a resource?
A user-supplied XML, bitmap, or other file, injected into the application build process, which can later be loaded from code.
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.
What's the difference between file, class and activity in android?
File - It is a block of arbitrary information, or resource for storing information. It can be of any type.
Class - Its a compiled form of .Java file . Android finally used this .class files to produce an executable apk
Activity - An activity is the equivalent of a Frame/Window in GUI toolkits. It is not a file or a file type it is just a class that can be extended in Android for loading UI elements on view.
What is a Sticky Intent?
sendStickyBroadcast() performs a sendBroadcast (Intent) that is "sticky," i.e. the Intent you are sending stays around after the broadcast is complete, so that others can quickly retrieve that data through the return value of registerReceiver (BroadcastReceiver, IntentFilter). In all other ways, this behaves the same as sendBroadcast(Intent).
One example of a sticky broadcast sent via the operating system is ACTION_BATTERY_CHANGED. When you call registerReceiver() for that action -- even with a null BroadcastReceiver -- you get the Intent that was last broadcast for that action. Hence, you can use this to find the state of the battery without necessarily registering for all future state changes in the battery.
Permissions.PROCESS_OUTGOING_CALLS: Allows an application to monitor, modify, or abort outgoing calls.
What's the difference between file, class and activity in android?
File - It is a block of arbitrary information, or resource for storing information. It can be of any type.
Class - Its a compiled form of .Java file . Android finally used this .class files to produce an executable apk
Activity - An activity is the equivalent of a Frame/Window in GUI toolkits. It is not a file or a file type it is just a class that can be extended in Android for loading UI elements on view.
What is a Sticky Intent?
sendStickyBroadcast() performs a sendBroadcast (Intent) that is "sticky," i.e. the Intent you are sending stays around after the broadcast is complete, so that others can quickly retrieve that data through the return value of registerReceiver (BroadcastReceiver, IntentFilter). In all other ways, this behaves the same as sendBroadcast(Intent).
One example of a sticky broadcast sent via the operating system is ACTION_BATTERY_CHANGED. When you call registerReceiver() for that action -- even with a null BroadcastReceiver -- you get the Intent that was last broadcast for that action. Hence, you can use this to find the state of the battery without necessarily registering for all future state changes in the battery.
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