1.Android Basic Knowledge points

1. What are the four components and their life cycle (and fragment)?

　Activity: Communication via intent, with data on actions and actions in the intent　

Broadcastreceive: You can start an activity or service in the broadcast in response to the received information, or use Notificationmanager to notify the user, you can filter the external data, only to respond to events of interest.

General broadcast: Context.sendboradcast (Intent)

Ordered broadcast: Context.sendorderbroadcast (intent,receiverpermission), Receiverpermission determines the level of broadcasting, the value is between 1000 and 1000, the greater the value, The higher the priority of the send. Received broadcasts can be prioritized by priority in the Intentfilter. Abortbroadcast () can truncate the broadcast.

Asynchronous broadcast: Sent via Context.sendstickybroadcast (intent). There are also sendstickyorderedbroadcast (intent, Resultreceiver, Scheduler, Initialcode, Initialdata, Initialextras) methods, This method has the characteristics of an ordered broadcast and also has the characteristics of asynchronous broadcasting; Send asynchronous broadcast to: <uses-permission android:name="Android.permission.BROADCAST_STICKY" / > permissions, after receiving and processing intent, the broadcast still exists until you call Removestickybroadcast (intent) to remove it.

To listen for broadcast intent: 1. Define a class to inherit Broadcastreceiver, and then override the OnReceive () method.

2. Static registration, registered directly in the manifest file or dynamic registration. Code in Registerreceiver (Receive,intentfilter), logoff Unregisterreceiver (receive).

The broadcast has a life cycle of only 10s, and if it does a time-consuming operation, it can result in ANR.

Service: How to use: 1. Inherit service, register in manifest file. Start with the StartService () or Bindservice () method.

The service started by the StartService () method has no relationship with the caller, even if the caller shuts down and the service is still running to stop the service to call Context.stopservice (), at which point the system calls Ondestory (), when started with this method, The first time the service starts the system calls the service's OnCreate ()-->onstart (), and if the service has started again the call will only trigger the OnStart () method

Services that are started with bindservice () are bound to the caller as long as the caller shuts down the service, and when started using this method, the first time the service starts the system calls the service's OnCreate ()-->onbind (), and if the service has started again, the call will no longer trigger these 2 methods , when the caller exits, the system invokes the service's Onunbind ()-->ondestory (), and the system calls Onunbind ()-->ondestory () in order to actively unbind the binding contex.unbindservice ();

ContentProvider: Other applications can obtain or deposit data from the content provider through the Contentresolver class (see contentprovideraccessapp example)

1.Android Basic Knowledge points