控件 -- Notification

一、概念

Notification，是一种具有全局效果的通知，可以在系统的通知栏中显示。当App向系统发出通知时，它将先以图标的形式显示在通知栏中。用户可以下拉通知栏查看通知的详细信息。通知栏和抽屉式通知栏均是由系统控制，用户可以随时查看。

二、使用

Notification的基本操作主要有创建、更新、取消这三种。
一个 Notification的必要属性有三项，如果不设置则在运行时会抛出异常：
小图标，通过 setSmallIcon() 方法设置；
标题，通过 setContentTitle() 方法设置；
内容，通过 setContentText() 方法设置。
除了以上三项，其它均为可选项。可以给 Notification设置一个 Action ，这样就可以直接跳转到App的某个Activity、启动一个 Service或者发送一个Broadcast。当系统接收到通知时，可以通过震动、响铃、呼吸灯等多种方式进行提醒。

1.创建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);
    //获取NotificationManager实例
    NotificationManager notifyManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
    //实例化NotificationCompat.Builde并设置相关属性
    NotificationCompat.Builder builder = new NotificationCompat.Builder(this)
            //设置小图标
            .setSmallIcon(R.mipmap.ic_launcher)
            //设置通知标题
            .setContentTitle("最简单的Notification")
            //设置通知内容
            .setContentText("只有小图标、标题、内容")
            //设置pendingIntent
            .setContentIntent(pendingIntent)
            //点击通知后自动清除
            .setAutoCancel(true);
    //通过builder.build()方法生成Notification对象,并发送通知,id=1
    notifyManager.notify(1, builder.build());
}

2.更新Notification

更新通知只需要再次发送相同ID的通知即可，如果之前的通知还未被取消，则会直接更新该通知相关的属性，如果之前的通知已经被取消，则会重新创建一个新通知。

3.取消Notification

取消通知有以下几种方式：
1.点击通知栏的清除按钮，会清除所有可清除的通知；
2.设置了setAutoCancel()或FLAG_AUTO_CANCEL的通知，点击该通知时会清除它；
3.通过NotificationManager调用cancel(int id)方法清除指定ID的通知；
4.通过NotificationManager调用cancel(String tag, int id)方法清除指定TAG和ID的通知；
5.通过NotificationManager调用cancelAll()方法清除所有该应用之前发送的通知。

如果是通过NotificationManager.notify(String tag, int id, Notification notify)方法创建的通知，那么只能通过NotificationManager.cancel(String tag, int id)方法才能清除对应的通知，调用NotificationManager.cancel(int id) 无效。

4.设置Notification的通知效果

Notification有震动、响铃、呼吸灯三种通知效果，可以通过setDefaults(int defualts)方法来设置。Default属性有以下四种，一旦设置了Default效果，自定义的效果就会失效。
默认通知效果：

//
Notification.DEFAULT_VIBRATE

//添加系统默认声音效果，设置此值后，调用setSound()设置自定义声音无效
Notification.DEFAULT_SOUND

//添加默认呼吸灯效果，使用时须与Notification.FLAG_SHOW_LIGHTS结合使用，否则无效
Notification.DEFAULT_LIGHTS

//添加上述三种默认提醒效果
Notification.DEFAULT_ALL

常用通知效果：

//三色灯提醒，在使用三色灯提醒时候必须加该标志符
Notification.FLAG_SHOW_LIGHTS

//发起正在运行事件（活动中）
Notification.FLAG_ONGOING_EVENT

//让声音、振动无限循环，直到用户响应（取消或者打开）
Notification.FLAG_INSISTENT

//发起Notification后，铃声和震动均只执行一次
Notification.FLAG_ONLY_ALERT_ONCE

//用户单击通知后自动消失
Notification.FLAG_AUTO_CANCEL

//只有调用NotificationManager.cancel()时才会清除
Notification.FLAG_NO_CLEAR

//表示正在运行的服务
Notification.FLAG_FOREGROUND_SERVICE

设置方法：

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、适配Android 8.0通知

1. AndroidManifest.xml

2. strings.xml

   OneNotification
   TwoNotification
   ThreeNotification
   

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 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");
   
           //适配Android 8.0, 创建通知渠道
           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