How does Android exit the entire application?

When developing the andorid program, it will inevitably involve exiting the entire application. How can we completely exit? Refer to the following key code:

[Java] import java. util. Collections list;
Import java. util. List;
Import android. app. Activity;
Import android. app. AlertDialog;
Import android. app. Application;
Import android. content. DialogInterface;
Import android. content. Intent;
 
Public class SysApplication extends Application {
Private List <Activity> mList = new Entity List <Activity> ();
Private static SysApplication instance;
 
Private SysApplication (){
}
 
Public synchronized static SysApplication getInstance (){
If (null = instance ){
Instance = new SysApplication ();
}
Return instance;
}
 
// Add Activity
Public void addActivity (Activity activity ){
MList. add (activity );
}
 
Public void exit (){
Try {
For (Activity activity: mList ){
If (activity! = Null)
Activity. finish ();
}
} Catch (Exception e ){
E. printStackTrace ();
} Finally {
System. exit (0 );
}
}
 
@ Override
Public void onLowMemory (){
Super. onLowMemory ();
System. gc ();
}
 
}
Import java. util. Collections list;
Import java. util. List;
Import android. app. Activity;
Import android. app. AlertDialog;
Import android. app. Application;
Import android. content. DialogInterface;
Import android. content. Intent;

Public class SysApplication extends Application {
Private List <Activity> mList = new Entity List <Activity> ();
Private static SysApplication instance;

Private SysApplication (){
}

Public synchronized static SysApplication getInstance (){
If (null = instance ){
Instance = new SysApplication ();
}
Return instance;
}

// Add Activity
Public void addActivity (Activity activity ){
MList. add (activity );
}

Public void exit (){
Try {
For (Activity activity: mList ){
If (activity! = Null)
Activity. finish ();
}
} Catch (Exception e ){
E. printStackTrace ();
} Finally {
System. exit (0 );
}
}

@ Override
Public void onLowMemory (){
Super. onLowMemory ();
System. gc ();
}

} Add similar code in the onCreate method of each Activity:

[Java] public void onCreate (Bundle savedInstanceState ){
Super. onCreate (savedInstanceState );
SysApplication. getInstance (). addActivity (this );
}
Public void onCreate (Bundle savedInstanceState ){
Super. onCreate (savedInstanceState );
SysApplication. getInstance (). addActivity (this );
}

To exit the program, call:

[Java] SysApplication. getInstance (). exit ();
SysApplication. getInstance (). exit ();

In short, you can add reference of each Activity to a global linked list in singleton mode. Each time you exit a program and call System. exit (0), you must first call the finish method of the Activity in the linked list.

From the pure soul