Information about Android devices

The ability to broadcast Intent between Android devices using data messages. After devices in the distance receive data information, Intent will be broadcast again. Various Applications can also broadcast their own intent receiver to other applications by using Context. broadcastIntent.

Instead of deleting the affected chapters, leave them here. For future versions of Android devices, the wizard may be used. In later Android versions, a complete set of interfaces for instant messaging functions will be exposed and these functions will be accessed through XMPP Based on IM services. It includes the management of contacts, logon prompts, and sending and receiving instant messages.

Google TalkGTalk) is an instant messaging protocol for P2P communication. Once connected, GTalk maintains the socket connection with the GTalk server, which means fast response time and low wait time. This section is based on earlier SDK implementations and uses GTalk. GTalk is based on the XMPP protocol and is a specific variant of Google. Currently, you need to have a Gmail account.

What makes GTalk services particularly interesting to developers? Is through the air OTA), the ability to broadcast Intent between Android devices using data messages. When a device in the distance receives the data information, it broadcasts the Intent again, just as it does locally. This means that this mechanism allows you to broadcast the Intent on a remote device.

The GTalk service can be used to create multi-user, communicative, or assisted applications. It provides a range of application frameworks, including distributed emergency warning systems, dynamic route-directed applications, family communication networks and powerful real-time game systems.

Android will eventually include all the interfaces used to create the GTalk instant messaging client, including full control over login management and subscription processing. If you like, you can build a replacement for the local client-or use related components in your own program.

Applications can save their data to files, SQL databases, or even any valid device. When you want to share your application data with other applications. Content Provider will be very useful. A Content Provider class implements a set of standard methods, so that other applications can save or read various data types processed by this Content Provider.

When we have clarified which construction blocks are required for our application, we need to register the list of these construction blocks in AndroidManifest. xml. This is an XML configuration file. This configuration file defines the components, functions, and necessary conditions of our application. This configuration file is required by every Android application. For the Schema of AndroidMainfest. xml, refer to the documentation attached to the SDK package.

Activity is the most basic type of Android block construction. In an application, an activity is usually a separate screen. Every activity is implemented as an independent class and inherits from the base class of Activity. This activity class will display the user interfaces composed of several Views controls and respond to the events.

Most applications contain multiple screens. For example, a short message application will have a screen for displaying the contact list, a second screen for writing short messages, and a screen for browsing old short messages and system settings. Every screen like this is an activity. It's easy to navigate from one screen to another. In some applications, a screen may even return a value to the previous screen.

When a new screen is opened, the previous screen is paused and saved in the history stack. You can return to the previous screen in the history stack. When the screen is no longer used, it can also be deleted from the history stack. By default, Android devices retain the running screen from the main screen to each application.