Android应用图标在状态栏上显示实现原理

2020-04-11 12:16:10

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一、前方
在研究《Android类似360,QQ管家那样的悬浮窗》突发奇想，想把应用的图标也显示到状态栏上，类似手机QQ，而有消息来时改变状态栏上的图标显示。

二、原理
其实很研究完后，才发现，很简单：
2.1 显示图标在状态栏上

复制代码代码如下:

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

// 将此通知放到通知栏的"Ongoing"即"正在运行"组中 
n.flags |= Notification.FLAG_ONGOING_EVENT; 
// 表明在点击了通知栏中的"清除通知"后，此通知不清除， 
// 经常与FLAG_ONGOING_EVENT一起使用 
n.flags |= Notification.FLAG_NO_CLEAR; 

PendingIntent pi = PendingIntent.getActivity(this, 0, getIntent(), 0); 
n.contentIntent = pi; 
n.setLatestEventInfo(this, "FloatsWindow", "start!", pi); 
nm.notify(NOTIFICATION_ID_ICON, n); 

2.2 修改图标的显示
不用cancel这个通知，只需传入不同的resId，再通知即可。

复制代码代码如下:

 
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.NotificationManager; 
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(); 
} 
/* 
* 显示应用主界面时，去除悬浮层 
* 修改状态栏上的图标 
*/ 
@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; 
mWindowMgrParams.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 在指悬浮在所有界面之上 
* (4.0+系统中，在下拉菜单下面，而在2.3中，在上拉菜单之上) 
*/ 
mWindowMgrParams.type = 2003; 
mWindowMgrParams.format = 1; 

/* 
* 代码实际是wmParams.flags |= FLAG_NOT_FOCUSABLE; 
* 40的由来是wmParams的默认属性（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 NOTIFICATION_ID_ICON = 0x10000; 
/* 
* 如果没有从状态栏中删除ICON，且继续调用addIconToStatusbar, 
* 则不会有任何变化。除了： 
* 如果，将notification中的resId设置不同的图标，则会显示不同 
* 的图标 
*/ 
private void addIconToStatusbar(int resId){ 
NotificationManager nm = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE); 
Notification n = new Notification( 
resId, "Floats Start!", System.currentTimeMillis()); 

// 将此通知放到通知栏的"Ongoing"即"正在运行"组中 
n.flags |= Notification.FLAG_ONGOING_EVENT; 
// 表明在点击了通知栏中的"清除通知"后，此通知不清除， 
// 经常与FLAG_ONGOING_EVENT一起使用 
n.flags |= Notification.FLAG_NO_CLEAR; 

PendingIntent pi = PendingIntent.getActivity(this, 0, getIntent(), 0); 
n.contentIntent = pi; 
n.setLatestEventInfo(this, "FloatsWindow", "start!", pi); 
nm.notify(NOTIFICATION_ID_ICON, n); 
} 

private void deleteIconToStatusbar(){ 
NotificationManager nm = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE); 
nm.cancel(NOTIFICATION_ID_ICON); 
} 
} 