The Android app icon is displayed on the status bar and different icons are displayed.

Ii. Principles

In fact, after the study, we found that it is very simple:

2.1 display icon on the status bar

[Java]
Icationicationmanager nm = (NotificationManager) getSystemService (Context. NOTIFICATION_SERVICE );
Notification n = new Notification (
ResId, "Floats Start! ", System. currentTimeMillis ());
 
// Place the notification to the "Ongoing" group in the notification bar, that is, the "running" group.
N. flags | = Notification. FLAG_ONGOING_EVENT;
// Indicates that the notification is not cleared after you click "clear notification" in the notification bar,
// Often used with FLAG_ONGOING_EVENT
N. flags | = Notification. FLAG_NO_CLEAR;
 
PendingIntent pi = PendingIntent. getActivity (this, 0, getIntent (), 0 );
N. contentIntent = pi;
N. setLatestEventInfo (this, "FloatsWindow", "start! ", Pi );
Nm. icationy (icationication_id_icon, n );

Icationicationmanager nm = (NotificationManager) getSystemService (Context. NOTIFICATION_SERVICE );
Notification n = new Notification (
ResId, "Floats Start! ", System. currentTimeMillis ());

// Place the notification to the "Ongoing" group in the notification bar, that is, the "running" group.
N. flags | = Notification. FLAG_ONGOING_EVENT;
// Indicates that the notification is not cleared after you click "clear notification" in the notification bar,
// Often used with FLAG_ONGOING_EVENT
N. flags | = Notification. FLAG_NO_CLEAR;

PendingIntent pi = PendingIntent. getActivity (this, 0, getIntent (), 0 );
N. contentIntent = pi;
N. setLatestEventInfo (this, "FloatsWindow", "start! ", Pi );
Nm. Y (icationication_id_icon, n); 2.2 modify the icon display

You don't need the cancel notification. You only need to pass in different resId and then send the notification.

[Java]
Package com. chris. floats. window;
 
Import android. OS. Bundle;
Import android. util. DisplayMetrics;
Import android. view. Gravity;
Import android. view. WindowManager;
Import android. app. Activity;
Import android. app. Notification;
Import android. app. icationicationmanager;
Import android. app. PendingIntent;
Import android. content. Context;
 
Public class MainActivity extends Activity {
 
Private static WindowManager mWindowMgr = null;
Private WindowManager. LayoutParams mWindowMgrParams = null;
Private static FloatsWindowView mFloatsWindowView = null;

@ Override
Protected void onCreate (Bundle savedInstanceState ){
Super. onCreate (savedInstanceState );
SetContentView (R. layout. activity_main );
}

@ Override
Protected void onStop (){
Super. onStop ();
DeleteIconToStatusbar ();
}
 
/*
* When the main application interface is displayed, the floating layer is removed.
* Modify the icon on the status bar
*/
@ Override
Public void onWindowFocusChanged (boolean hasFocus ){
If (hasFocus ){
If (mFloatsWindowView! = Null ){
MWindowMgr. removeView (mFloatsWindowView );
MFloatsWindowView = null;
}
AddIconToStatusbar (R. drawable. a0 );
} Else {
GetWindowLayout ();
AddIconToStatusbar (R. drawable. ic_launcher );
}
}
 
Private void initParams (){
DisplayMetrics dm = getResources (). getDisplayMetrics ();
MWindowMgrParams. x = dm. widthPixels-136;
Mwindowsmgrparams. y = 300;
MWindowMgrParams. width = 136;
MWindowMgrParams. height = 136;
}
 
Private void getWindowLayout (){
If (mFloatsWindowView = null ){
MWindowMgr = (WindowManager) getBaseContext (). getSystemService (Context. WINDOW_SERVICE );
MWindowMgrParams = new WindowManager. LayoutParams ();

/*
* 2003 floating on all interfaces
* (In the 4.0 + system, under the drop-down menu, and in the 2.3 system, above the top menu)
*/
Mwindows mgrparams. type = 2003;
MWindowMgrParams. format = 1;

/*
* The actual code is wmParams. flags | = FLAG_NOT_FOCUSABLE;
* 40 is the default property of wmParams (32) + FLAG_NOT_FOCUSABLE (8)
*/
MWindowMgrParams. flags = 40;
MWindowMgrParams. gravity = Gravity. LEFT | Gravity. TOP;
InitParams ();

MFloatsWindowView = new FloatsWindowView (this );
MWindowMgr. addView (mFloatsWindowView, mWindowMgrParams );
}
}

Private final static int icationication_id_icon = 0x10000;
/*
* If the ICON is not deleted from the status bar and addIconToStatusbar is called,
* There will be no changes. Except:
* If you set different icons for resId in notification, different icons are displayed.
* Icon
*/
Private void addIconToStatusbar (int resId ){
Icationicationmanager nm = (NotificationManager) getSystemService (Context. NOTIFICATION_SERVICE );
Notification n = new Notification (
ResId, "Floats Start! ", System. currentTimeMillis ());

// Place the notification to the "Ongoing" group in the notification bar, that is, the "running" group.
N. flags | = Notification. FLAG_ONGOING_EVENT;
// Indicates that the notification is not cleared after you click "clear notification" in the notification bar,
// Often used with FLAG_ONGOING_EVENT
N. flags | = Notification. FLAG_NO_CLEAR;

PendingIntent pi = PendingIntent. getActivity (this, 0, getIntent (), 0 );
N. contentIntent = pi;
N. setLatestEventInfo (this, "FloatsWindow", "start! ", Pi );
Nm. icationy (icationication_id_icon, n );
}

Private void deleteIconToStatusbar (){
Icationicationmanager nm = (NotificationManager) getSystemService (Context. NOTIFICATION_SERVICE );
Nm. cancel (icationication_id_icon );
}
}

Package com. chris. floats. window;

Import android. OS. Bundle;
Import android. util. DisplayMetrics;
Import android. view. Gravity;
Import android. view. WindowManager;
Import android. app. Activity;
Import android. app. Notification;
Import android. app. icationicationmanager;
Import android. app. PendingIntent;
Import android. content. Context;

Public class MainActivity extends Activity {

Private static WindowManager mWindowMgr = null;
Private WindowManager. LayoutParams mWindowMgrParams = null;
Private static FloatsWindowView mFloatsWindowView = null;
 
@ Override
Protected void onCreate (Bundle savedInstanceState ){
Super. onCreate (savedInstanceState );
SetContentView (R. layout. activity_main );
}
 
@ Override
Protected void onStop (){
Super. onStop ();
DeleteIconToStatusbar ();
}

/*
* When the main application interface is displayed, the floating layer is removed.
* Modify the icon on the status bar
*/
@ Override
Public void onWindowFocusChanged (boolean hasFocus ){
If (hasFocus ){
If (mFloatsWindowView! = Null ){
MWindowMgr. removeView (mFloatsWindowView );
MFloatsWindowView = null;
}
AddIconToStatusbar (R. drawable. a0 );
} Else {
GetWindowLayout ();
AddIconToStatusbar (R. drawable. ic_launcher );
}
}

Private void initParams (){
DisplayMetrics dm = getResources (). getDisplayMetrics ();
MWindowMgrParams. x = dm. widthPixels-136;
Mwindowsmgrparams. y = 300;
MWindowMgrParams. width = 136;
MWindowMgrParams. height = 136;
}

Private void getWindowLayout (){
If (mFloatsWindowView = null ){
MWindowMgr = (WindowManager) getBaseContext (). getSystemService (Context. WINDOW_SERVICE );
MWindowMgrParams = new WindowManager. LayoutParams ();

/*
* 2003 floating on all interfaces
* (In the 4.0 + system, under the drop-down menu, and in the 2.3 system, above the top menu)
*/
Mwindows mgrparams. type = 2003;
MWindowMgrParams. format = 1;

/*
* The actual code is wmParams. flags | = FLAG_NOT_FOCUSABLE;
* 40 is the default property of wmParams (32) + FLAG_NOT_FOCUSABLE (8)
*/
MWindowMgrParams. flags = 40;
MWindowMgrParams. gravity = Gravity. LEFT | Gravity. TOP;
InitParams ();

MFloatsWindowView = new FloatsWindowView (this );
MWindowMgr. addView (mFloatsWindowView, mWindowMgrParams );
}
}
 
Private final static int icationication_id_icon = 0x10000;
/*
* If the ICON is not deleted from the status bar and addIconToStatusbar is called,
* There will be no changes. Except:
* If you set different icons for resId in notification, different icons are displayed.
* Icon
*/
Private void addIconToStatusbar (int resId ){
Icationicationmanager nm = (NotificationManager) getSystemService (Context. NOTIFICATION_SERVICE );
Notification n = new Notification (
ResId, "Floats Start! ", System. currentTimeMillis ());

// Place the notification to the "Ongoing" group in the notification bar, that is, the "running" group.
N. flags | = Notification. FLAG_ONGOING_EVENT;
// Indicates that the notification is not cleared after you click "clear notification" in the notification bar,
// Often used with FLAG_ONGOING_EVENT
N. flags | = Notification. FLAG_NO_CLEAR;

PendingIntent pi = PendingIntent. getActivity (this, 0, getIntent (), 0 );
N. contentIntent = pi;
N. setLatestEventInfo (this, "FloatsWindow", "start! ", Pi );
Nm. icationy (icationication_id_icon, n );
}
 
Private void deleteIconToStatusbar (){
Icationicationmanager nm = (NotificationManager) getSystemService (Context. NOTIFICATION_SERVICE );
Nm. cancel (icationication_id_icon );
}
}
The above is the source code. When the focus of the application changes, the image on the status bar also changes.