android 9适配通知栏 - 好文

最近安装了一个9.0的模拟器，发现通知栏不显示，也没有任何打印日志，把过滤条件改成“No Filters”就可以看到
2018-11-07 14:52:03.987 1908-1992/? E/NotificationService: No Channel found
for pkg=com.dahai.floatnotes, channelId=id, id=1, tag=null,
opPkg=com.dahai.floatnotes, callingUid=10087, userId=0, incomingUserId=0,
notificationUid=10087, notification=Notification(channel=id pri=0
contentView=null vibrate=null sound=null defaults=0x0 flags=0x0
color=0xff008577 category=reminder vis=PRIVATE)
以前设置通知的代码,在8.0没有问题
NotificationCompat.Builder notificationCompatBuilder = new
NotificationCompat.Builder(getApplicationContext(), "packageName");
Notification notification = notificationCompatBuilder // Title for API <16 (4.0
and below) devices. .setContentTitle("标题") // Content for API <24 (7.0 and
below) devices. .setContentText("内容") .setSmallIcon(R.mipmap.ic_launcher)
.setLargeIcon(BitmapFactory.decodeResource( getResources(), R.mipmap.ic_logo))
.setContentIntent(notifyPendingIntent)
.setDefaults(NotificationCompat.DEFAULT_ALL)
.setColor(ContextCompat.getColor(getApplicationContext(),
R.color.colorPrimary)) .setCategory(Notification.CATEGORY_REMINDER)
.setPriority(NotificationCompat.PRIORITY_DEFAULT) .build();
NotificationManagerCompat.from(getApplicationContext()).notify(1, notification);
查看了官方文档介绍找了很久才找到如何解决官方描述
<https://developer.android.google.cn/about/versions/pie/android-9.0>
现在在设置渠道的时候需要设置到系统中去
public static String createNotificationChannel(Context context) { if
(Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) { String channelId =
"channelId"; CharSequence channelName = "channelName"; String
channelDescription ="channelDescription"; int channelImportance =
NotificationManager.IMPORTANCE_DEFAULT; NotificationChannel notificationChannel
= new NotificationChannel(channelId, channelName, channelImportance); // 设置描述
最长30字符 notificationChannel.setDescription(channelDescription); // 该渠道的通知是否使用震动
notificationChannel.enableVibration(true); // 设置显示模式
notificationChannel.setLockscreenVisibility(NotificationCompat.VISIBILITY_PUBLIC);
NotificationManager notificationManager = (NotificationManager)
context.getSystemService(Context.NOTIFICATION_SERVICE);
notificationManager.createNotificationChannel(notificationChannel); return
channelId; } else { return null; } } NotificationCompat.Builder
notificationCompatBuilder = new
NotificationCompat.Builder(getApplicationContext(),
createNotificationChannel(mContext)); Notification notification =
notificationCompatBuilder // Title for API <16 (4.0 and below) devices.
.setContentTitle("标题") // Content for API <24 (7.0 and below) devices.
.setContentText("内容") .setSmallIcon(R.mipmap.ic_launcher)
.setLargeIcon(BitmapFactory.decodeResource( getResources(), R.mipmap.ic_logo))
.setContentIntent(notifyPendingIntent)
.setDefaults(NotificationCompat.DEFAULT_ALL)
.setColor(ContextCompat.getColor(getApplicationContext(),
R.color.colorPrimary)) .setCategory(Notification.CATEGORY_REMINDER)
.setPriority(NotificationCompat.PRIORITY_DEFAULT) .build();
NotificationManagerCompat.from(getApplicationContext()).notify(1, notification);
这样就能显示出来了

还有一个问题startForeground
这里也要传入一个通知，如果不错适配会直接报错
android.app.RemoteServiceException: Bad notification for startForeground:
java.lang.RuntimeException: invalid channel for service notification:
Notification(channel=id pri=0 contentView=null vibrate=null sound=null
defaults=0x0 flags=0x40 color=0xff008577 vis=PRIVATE) at
android.app.ActivityThread$H.handleMessage(ActivityThread.java:1737) at
android.os.Handler.dispatchMessage(Handler.java:106) at
android.os.Looper.loop(Looper.java:193) at
android.app.ActivityThread.main(ActivityThread.java:6669) at
java.lang.reflect.Method.invoke(Native Method) at
com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
该问题的解决方法和通知栏一样，不过还要加一个权限<uses-permission
android:name="android.permission.FOREGROUND_SERVICE"/> 该权限是普通权限，可以直接添加

推荐一款应用悬浮笔记 <https://www.coolapk.com/apk/207959>，以上问题都在这个APP中出现过并已解决

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