一、概念

Notification，是一種具有全局效果的通知，可以在系統(tǒng)的通知欄中顯示。當(dāng)App向系統(tǒng)發(fā)出通知時(shí)，它將先以圖標(biāo)的形式顯示在通知欄中。用戶可以下拉通知欄查看通知的詳細(xì)信息。通知欄和抽屜式通知欄均是由系統(tǒng)控制，用戶可以隨時(shí)查看。

二、使用

Notification的基本操作主要有創(chuàng)建、更新、取消這三種。
一個(gè) Notification的必要屬性有三項(xiàng)，如果不設(shè)置則在運(yùn)行時(shí)會(huì)拋出異常：
小圖標(biāo)，通過 setSmallIcon() 方法設(shè)置；
標(biāo)題，通過 setContentTitle() 方法設(shè)置；
內(nèi)容，通過 setContentText() 方法設(shè)置。
除了以上三項(xiàng)，其它均為可選項(xiàng)?？梢越o Notification設(shè)置一個(gè) Action ，這樣就可以直接跳轉(zhuǎn)到App的某個(gè)Activity、啟動(dòng)一個(gè) Service或者發(fā)送一個(gè)Broadcast。當(dāng)系統(tǒng)接收到通知時(shí)，可以通過震動(dòng)、響鈴、呼吸燈等多種方式進(jìn)行提醒。

1.創(chuàng)建Notification

import android.support.v4.app.NotificationCompat;
private void testNotification() {
    Intent intent = new Intent(this, MainActivity.class);
    PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
    //獲取NotificationManager實(shí)例
    NotificationManager notifyManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
    //實(shí)例化NotificationCompat.Builde并設(shè)置相關(guān)屬性
    NotificationCompat.Builder builder = new NotificationCompat.Builder(this)
            //設(shè)置小圖標(biāo)
            .setSmallIcon(R.mipmap.ic_launcher)
            //設(shè)置通知標(biāo)題
            .setContentTitle("最簡(jiǎn)單的Notification")
            //設(shè)置通知內(nèi)容
            .setContentText("只有小圖標(biāo)、標(biāo)題、內(nèi)容")
            //設(shè)置pendingIntent
            .setContentIntent(pendingIntent)
            //點(diǎn)擊通知后自動(dòng)清除
            .setAutoCancel(true);
    //通過builder.build()方法生成Notification對(duì)象,并發(fā)送通知,id=1
    notifyManager.notify(1, builder.build());
}

2.更新Notification

更新通知只需要再次發(fā)送相同ID的通知即可，如果之前的通知還未被取消，則會(huì)直接更新該通知相關(guān)的屬性，如果之前的通知已經(jīng)被取消，則會(huì)重新創(chuàng)建一個(gè)新通知。

3.取消Notification

取消通知有以下幾種方式：
1.點(diǎn)擊通知欄的清除按鈕，會(huì)清除所有可清除的通知；
2.設(shè)置了setAutoCancel()或FLAG_AUTO_CANCEL的通知，點(diǎn)擊該通知時(shí)會(huì)清除它；
3.通過NotificationManager調(diào)用cancel(int id)方法清除指定ID的通知；
4.通過NotificationManager調(diào)用cancel(String tag, int id)方法清除指定TAG和ID的通知；
5.通過NotificationManager調(diào)用cancelAll()方法清除所有該應(yīng)用之前發(fā)送的通知。

如果是通過NotificationManager.notify(String tag, int id, Notification notify)方法創(chuàng)建的通知，那么只能通過NotificationManager.cancel(String tag, int id)方法才能清除對(duì)應(yīng)的通知，調(diào)用NotificationManager.cancel(int id) 無效。

4.設(shè)置Notification的通知效果

Notification有震動(dòng)、響鈴、呼吸燈三種通知效果，可以通過setDefaults(int defualts)方法來設(shè)置。Default屬性有以下四種，一旦設(shè)置了Default效果，自定義的效果就會(huì)失效。
默認(rèn)通知效果：

//<uses-permission android:name="android.permission.VIBRATE" />
Notification.DEFAULT_VIBRATE

//添加系統(tǒng)默認(rèn)聲音效果，設(shè)置此值后，調(diào)用setSound()設(shè)置自定義聲音無效
Notification.DEFAULT_SOUND

//添加默認(rèn)呼吸燈效果，使用時(shí)須與Notification.FLAG_SHOW_LIGHTS結(jié)合使用，否則無效
Notification.DEFAULT_LIGHTS

//添加上述三種默認(rèn)提醒效果
Notification.DEFAULT_ALL

常用通知效果：

//三色燈提醒，在使用三色燈提醒時(shí)候必須加該標(biāo)志符
Notification.FLAG_SHOW_LIGHTS

//發(fā)起正在運(yùn)行事件（活動(dòng)中）
Notification.FLAG_ONGOING_EVENT

//讓聲音、振動(dòng)無限循環(huán)，直到用戶響應(yīng)（取消或者打開）
Notification.FLAG_INSISTENT

//發(fā)起Notification后，鈴聲和震動(dòng)均只執(zhí)行一次
Notification.FLAG_ONLY_ALERT_ONCE

//用戶單擊通知后自動(dòng)消失
Notification.FLAG_AUTO_CANCEL

//只有調(diào)用NotificationManager.cancel()時(shí)才會(huì)清除
Notification.FLAG_NO_CLEAR

//表示正在運(yùn)行的服務(wù)
Notification.FLAG_FOREGROUND_SERVICE

設(shè)置方法：

NotificationCompat.Builder#setDefaults
NotificationCompat.Builder#setSound
NotificationCompat.Builder#setVibrate
NotificationCompat.Builder#setLights

notification.defaults
notification.sound
notification.vibrate
notification.ledARGB
notification.ledOnMS
notification.ledOffMS
notification.flags

三、適配Android 8.0通知

1. AndroidManifest.xml

   <receiver android:name=".TestBroadcastReceiver">
       <intent-filter>
           <action android:name="com.tomorrow.intent.action.test"/>
       </intent-filter>
   </receiver>
   

2. strings.xml

   <string name="one_notification">OneNotification</string>
   <string name="two_notification">TwoNotification</string>
   <string name="three_notification">ThreeNotification</string>
   

3. NotificationChannelController

   public class NotificationChannelController {
       public static final String CHANNEL_ID_ONE_NOTIFICATION = "CHANNEL_ID_ONE_NOTIFICATION";
       public static final String CHANNEL_ID_TWO_NOTIFICATION = "CHANNEL_ID_TWO_NOTIFICATION";
       public static final String CHANNEL_ID_THREE_NOTIFICATION = "CHANNEL_ID_THREE_NOTIFICATION";
   
       @RequiresApi(api = Build.VERSION_CODES.O)
       private enum Channel {
           ONE_NOTIFICATION(CHANNEL_ID_ONE_NOTIFICATION, R.string.one_notification, NotificationManager.IMPORTANCE_LOW, true),
           TWO_NOTIFICATION(CHANNEL_ID_TWO_NOTIFICATION, R.string.two_notification, NotificationManager.IMPORTANCE_DEFAULT, false),
           THREE_NOTIFICATION(CHANNEL_ID_THREE_NOTIFICATION, R.string.three_notification, NotificationManager.IMPORTANCE_HIGH, true);
   
           private final String id;
           private final int nameResId;
           private final int importance;
           private final boolean showBadge;
   
           Channel(String id, @StringRes int nameResId, int importance, boolean showBadge) {
               this.id = id;
               this.nameResId = nameResId;
               this.importance = importance;
               this.showBadge = showBadge;
           }
   
           public String getId() {
               return id;
           }
   
           public int getNameResId() {
               return nameResId;
           }
   
           public int getImportance() {
               return importance;
           }
   
           public boolean canShowBadge() {
               return showBadge;
           }
       }
   
       public static void createChannels(Context context) {
           if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
               final NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
               List<NotificationChannel> channelList = new ArrayList<>();
               for (Channel channel : Channel.values()) {
                   NotificationChannel notificationChannel = new NotificationChannel(channel.getId(), context.getString(channel.getNameResId()), channel.getImportance());
                   notificationChannel.setShowBadge(channel.canShowBadge());
                   channelList.add(notificationChannel);
               }
               if (notificationManager != null) {
                   notificationManager.createNotificationChannels(channelList);
               }
           }
       }
   }
   

4. MainActivity

   import android.app.PendingIntent;
   import android.content.Intent;
   import android.graphics.Bitmap;
   import android.graphics.BitmapFactory;
   import android.os.Bundle;
   import android.support.v4.app.NotificationCompat;
   import android.support.v4.app.NotificationManagerCompat;
   import android.support.v7.app.AppCompatActivity;
   import android.util.Log;
   
   public class MainActivity extends AppCompatActivity {
       private static final String TAG = MainActivity.class.getSimpleName();
       private TestBroadcastReceiver mReceiver;
   
       @Override
       protected void onCreate(Bundle savedInstanceState) {
           super.onCreate(savedInstanceState);
           setContentView(R.layout.activity_main);
           Log.d(TAG, "zwm, onCreate");
   
           //適配Android 8.0, 創(chuàng)建通知渠道
           NotificationChannelController.createChannels(getApplicationContext());
           Intent intent = new Intent("com.tomorrow.intent.action.test");
           intent.setPackage(getPackageName());
           PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
           Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher);
           NotificationCompat.Builder builder = new NotificationCompat.Builder(this, NotificationChannelController.CHANNEL_ID_THREE_NOTIFICATION);
           builder.setShowWhen(true)
                   .setContentTitle("notification title")
                   .setContentText("notification content")
                   .setLargeIcon(bitmap)
                   .setSmallIcon(R.mipmap.ic_launcher)
                   .setStyle(new NotificationCompat.BigTextStyle().bigText("BigTextStyle content"))
                   .setContentIntent(pendingIntent)
                   .setAutoCancel(true);
           NotificationManagerCompat.from(this).notify(99, builder.build());
       }
   }
   

5. TestBroadcastReceiver

   public class TestBroadcastReceiver extends BroadcastReceiver {
       private static final String TAG = "TestBroadcastReceiver";
       @Override
       public void onReceive(Context context, Intent intent) {
           Log.d(TAG, "zwm, onReceive, action: " + intent.getAction());
       }
   }
   

6. 打印日志

   2020-03-26 13:26:30.397 20445-20445/com.tomorrow.architetest D/MainActivity: zwm, onCreate
   2020-03-26 13:26:50.909 20445-20445/com.tomorrow.architetest D/TestBroadcastReceiver: zwm, onReceive, action: com.tomorrow.intent.action.test