Usage of bindservice in Android

Reprinted from: http://www.cnblogs.com/onlylittlegod/archive/2011/05/15/2046652.html

Recently I learned about the service application in Android, and got stuck in the bindservice section, mainly because I didn't fully understand why it was implemented.

Bindservice and started service are both services. What is the difference:

1. the startservice () method is used in the started service to call the method. There is no connection between the caller and the service. Even if the caller exits, the Service continues to [oncreate ()-> onstartcommand () -> startservice ()-> ondestroy ()]. Note that there is no onstart (), which is mainly replaced by the onstartcommand () method. The onstart method is not recommended.

2. bindservice uses the bindservice () method to bind the service. When the caller and the biner are bound together, the consumer terminates the [oncreate ()-> onbind ()-> onunbind () -> ondestroy ()].

Caller activity:

Mainactivity

 1   Mainacitvity  2   3  Package  Com. zys. Service;  4   5   Import  Com. zys. Service. bindservice. mybinder;  6   7   Import  Android. R. bool;  8   Import  Android. App. activity;  9   Import  Android. content. componentname; 10   Import  Android. content. context;  11   Import  Android. content. intent;  12   Import  Android. content. serviceconnection;  13   Import  Android. OS. Bundle;  14   Import  Android. OS. ibinder;  15  Import  Android. View. view;  16   Import  Android. View. View. onclicklistener;  17   Import  Android. widget. Button;  18   19   Public   Class Mainactivity Extends  Activity {  20       Private Button startbtn;  21       Private  Button stopbtn;  22       Private   Boolean  Flag;  23       /**  Called when the activity is first created.  */  24   @ Override  25       Public  Void  Oncreate (bundle savedinstancestate ){  26           Super  . Oncreate (savedinstancestate );  27   Setcontentview (R. layout. Main );  28 Flag = False  ;  29           //  Set  30 Startbtn = (button) This . Findviewbyid (R. Id. startbtn );  31 Stopbtn = (button) This  . Findviewbyid (R. Id. stopbtn );  32   Startbtn. setonclicklistener (listener );  33   Stopbtn. setonclicklistener (listener );  34   }  35       36       Private Onclicklistener listener = New Onclicklistener (){  37           38   @ Override  39           Public   Void  Onclick (view v ){  40               //  Todo auto-generated method stub  41               Switch  (V. GETID ()){  42               Case R. Id. startbtn:  43   Bindservice ();  44                   Break  ;  45               Case  R. Id. stopbtn:  46   Unbind ();  47                   Break  ;  48               Default  : 49                   Break  ;  50   }  51   }  52           53           54   };  55       56       Private   Void  Bindservice (){  57 Intent intent =New Intent (mainactivity. This , Bindservice. Class  );  58   Bindservice (intent, Conn, context. bind_auto_create );  59   }  60       61       Private   Void  Unbind (){  62           If (Flag =True  ){  63   Unbindservice (conn );  64 Flag = False  ;  65   }  66   }  67       68       Private Serviceconnection conn = New  Serviceconnection (){ 69           70   @ Override  71           Public   Void  Onservicedisconnected (componentname name ){  72               //  Todo auto-generated method stub  73               74   }  75           76   @ Override 77           Public   Void  Onserviceconnected (componentname name, ibinder Service ){  78               //  Todo auto-generated method stub  79 Mybinder binder = (Mybinder) service;  80 Bindservice = Binder. getservice ();  81   Bindservice. mymethod ();  82 Flag = True  ;  83   }  84   };  85       86 }

Service bindservice:

Bindservice

 Bindservice  Package  Com. zys. Service;  Import  Java. Io. filedescriptor;  Import Android. App. Service;  Import  Android. content. intent;  Import  Android. OS. Binder;  Import  Android. OS. ibinder;  Import  Android. OS. iinterface;  Import  Android. OS. parcel;  Import  Android. OS. RemoteException;  Import  Android. util. log; Public   Class Bindservice Extends  Service {  Private   Static   Final String tag = "bindservice" ;  Public   Void  Mymethod () {log. I (tag, "Bindservice --> mymethod ()" ) ;}@ Override  Public  Ibinder onbind (intent ){ //  Todo auto-generated method stub          Return  Mybinder ;}  Public   Class Mybinder Extends  Binder {  Public  Bindservice getservice (){  Return Bindservice. This  ;}}  Private Mybinder =New  Mybinder ();} 

Because the service in Android uses the onbind method to bind the service, an ibinder object is returned for operation. When we want to obtain the content of the specific service method, we need to return a specific service object for the ibinder object to operate. Therefore, the specific service object must first implement the binder object. In this way, we can use the bindservice method to bind the service, after obtaining the binder object, obtain the specific service object, and then obtain the methods in the service. Therefore, we need to note that the bindservice method to bind the Service must implement the binder object, therefore, we must use the binder method to obtain the service instead of directly using the service class. This is restricted by the internal implementation of Android.

The procedure is as follows:

Intent intent = new intent (mainactivity. This, bindservice. Class)-> New bindservice object-> New mybinder object

-> Bindservice (intent, Conn, context. bind_auto_create);-> onbind () function ----- pass the mybinder object -------> onserviceconnected () --> get the bindservice object corresponding to the binder object through the passed binder object --> call the method defined in service.

This must be passed through the binder object, because it is passed through the binder object, get the service object through the binder object, and then get the required service, so the Service must implement the binder for transmission and use.