Android runs atop a Linux kernel. Android applications are written in the Java programming language, and they run within a virtual machine (VM). Each Android application runs within an instance of the Dalvik VM (an open source technology), which in turn resides within a Linux-kernel managed process
An Android application consists of one or more of the following classifications [10]:
Activities. An application that has a visible UI is implemented with an activity.
When a user selects an application from the home screen or application launcher,
an activity is started.
Services. A service should be used for any application that needs to persist for a
long time, such as a network monitor or update-checking application.
Content providers. You can think of content providers as a database server. A
content provider's job is to manage access to persisted data, such as a SQLite
database. If your application is very simple, you might not necessarily create a
content provider. If you're building a larger application, or one that makes data
available to multiple activities or applications, a content provider is the means of
accessing your data.
Broadcast receivers. An Android application may be launched to process a
element of data or respond to an event, such as the receipt of a text message.
An Android application along with a file called AndroidManifest.xml is deployed to a
device. The AndroidManifest.xml contains the necessary configuration information properly
installed to the device. It includes the required class names and types of events the application
is able to process, and the required permissions the application needs to run. For example, if
an application requires access to the network — to download a file, for example — this
permission must be explicitly stated in the manifest file. Many applications may have this
specific permission enabled. Such declarative security helps reduce the likelihood that a rogue
application can cause damage on your device.
Android runs atop a Linux kernel. Android applications are written in the Java programming language, and they run within a virtual machine (VM). Each Android application runs within an instance of the Dalvik VM (an open source technology), which in turn resides within a Linux-kernel managed process
An Android application consists of one or more of the following classifications [10]:
Activities. An application that has a visible UI is implemented with an activity.
When a user selects an application from the home screen or application launcher,
an activity is started.
Services. A service should be used for any application that needs to persist for a
long time, such as a network monitor or update-checking application.
Content providers. You can think of content providers as a database server. A
content provider's job is to manage access to persisted data, such as a SQLite
database. If your application is very simple, you might not necessarily create a
content provider. If you're building a larger application, or one that makes data
available to multiple activities or applications, a content provider is the means of
accessing your data.
Broadcast receivers. An Android application may be launched to process a
element of data or respond to an event, such as the receipt of a text message.
An Android application along with a file called AndroidManifest.xml is deployed to a
device. The AndroidManifest.xml contains the necessary configuration information properly
installed to the device. It includes the required class names and types of events the application
is able to process, and the required permissions the application needs to run. For example, if
an application requires access to the network — to download a file, for example — this
permission must be explicitly stated in the manifest file. Many applications may have this
specific permission enabled. Such declarative security helps reduce the likelihood that a rogue
application can cause damage on your device.
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