奥利奥没有显示通知

Question

普通通知生成器不会在Android O上显示通知。

如何在Android 8 Oreo上显示通知？

是否有任何新代码要添加以在Android O上显示通知？

Answer 1

在Android O中，必须在Notification Builder中使用频道

下面是一个示例代码：

// Sets an ID for the notification, so it can be updated.
int notifyID = 1; 
String CHANNEL_ID = "my_channel_01";// The id of the channel. 
CharSequence name = getString(R.string.channel_name);// The user-visible name of the channel.
int importance = NotificationManager.IMPORTANCE_HIGH;
NotificationChannel mChannel = new NotificationChannel(CHANNEL_ID, name, importance);
// Create a notification and set the notification channel.
Notification notification = new Notification.Builder(MainActivity.this)
            .setContentTitle("New Message")
            .setContentText("You've received new messages.")
            .setSmallIcon(R.drawable.ic_notify_status)
            .setChannelId(CHANNEL_ID)
            .build();

或者处理兼容性：

NotificationCompat notification =
        new NotificationCompat.Builder(this)
        .setSmallIcon(R.drawable.notification_icon)
        .setContentTitle("My notification")
        .setContentText("Hello World!")
        .setChannelId(CHANNEL_ID).build();



NotificationManager mNotificationManager =
            (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
 mNotificationManager.createNotificationChannel(mChannel);

// Issue the notification.
mNotificationManager.notify(notifyID , notification);

或者如果您想要一个简单的修复，那么使用以下代码：

NotificationManager mNotificationManager =
            (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
       mNotificationManager.createNotificationChannel(mChannel);
    }

更新：NotificationCompat.Builder reference

NotificationCompat.Builder(Context context)

这个构造函数在API级别26.0.0中已弃用，因此您应该使用

Builder(Context context, String channelId)

所以不需要setChannelId与新的构造函数。

您应该使用当前最新的AppCompat库26.0.2

compile "com.android.support:appcompat-v7:26.0.+"

来自Android Developers Channel on Youtube的消息来源

此外，你可以检查official Android Docs

Answer 2

这是你如何做到的

private fun sendNotification() {
    val notificationId = 100
    val chanelid = "chanelid"
    val intent = Intent(this, MainActivity::class.java)
    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK)
    val pendingIntent = PendingIntent.getActivity(this, 0, intent, 0)
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) { // you must create a notification channel for API 26 and Above
        val name = "my channel"
        val description = "channel description"
        val importance = NotificationManager.IMPORTANCE_DEFAULT
        val channel = NotificationChannel(chanelid, name, importance);
        channel.setDescription(description);
        // Register the channel with the system; you can't change the importance
        // or other notification behaviors after this
        val notificationManager = getSystemService(NotificationManager::class.java)
        notificationManager.createNotificationChannel(channel)
    }

    val mBuilder = NotificationCompat.Builder(this, chanelid)
            .setSmallIcon(R.drawable.ic_notification)
            .setContentTitle("Want to Open My App?")
            .setContentText("Open my app and see good things")
            .setPriority(NotificationCompat.PRIORITY_DEFAULT)
            .setContentIntent(pendingIntent)
            .setAutoCancel(true) // cancel the notification when clicked
            .addAction(R.drawable.ic_check, "YES", pendingIntent) //add a btn to the Notification with a corresponding intent

    val notificationManager = NotificationManagerCompat.from(this);
    notificationManager.notify(notificationId, mBuilder.build());
}

阅读=> https://developer.android.com/training/notify-user/build-notification的完整教程

Answer 3

对于在尝试上述解决方案后遇到此问题的任何人，请确保在创建通知渠道时使用的渠道ID与您在“通知”构建器中设置的渠道ID相同。

const val CHANNEL_ID = "EXAMPLE_CHANNEL_ID"

// create notification channel
val notificationChannel = NotificationChannel(CHANNEL_ID, 
NOTIFICATION_NAME, NotificationManager.IMPORTANCE_HIGH)

// building notification
NotificationCompat.Builder(context)
                    .setSmallIcon(android.R.drawable.ic_input_add)
                    .setContentTitle("Title")
                    .setContentText("Subtitle")   
                    .setPriority(NotificationCompat.PRIORITY_MAX)
                    .setChannelId(CHANNEL_ID)

Answer 4

private void addNotification() {
                NotificationCompat.Builder builder =
                new NotificationCompat.Builder(this)
                .setSmallIcon(R.drawable.ic_launcher_background)
                .setContentTitle("Notifications Example")
                .setContentText("This is a test notification");
                Intent notificationIntent = new Intent(this, MainActivity.class);
                PendingIntent contentIntent = PendingIntent.getActivity(this, 0, notificationIntent,
                PendingIntent.FLAG_UPDATE_CURRENT);
                builder.setContentIntent(contentIntent);
                // Add as notification
                NotificationManager manager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
                if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O)
                {
                NotificationChannel nChannel = new NotificationChannel(NOTIFICATION_CHANNEL_ID, "NOTIFICATION_CHANNEL_NAME", NotificationManager.IMPORTANCE_HIGH);
                nChannel.enableLights(true);
                assert manager != null;
                builder.setChannelId(NOTIFICATION_CHANNEL_ID);
                manager.createNotificationChannel(nChannel);
                }
                assert manager != null;
                manager.notify(0, builder.build());
    }

Answer 5

在android Oreo中，通知应用程序是通过使用渠道和NotificationHelper类完成的。它应该有一个频道ID和频道名称。

首先，你必须创建一个NotificationHelper类

public class NotificationHelper扩展ContextWrapper {

private static final String EDMT_CHANNEL_ID="com.example.safna.notifier1.EDMTDEV";
private static final String EDMT_CHANNEL_NAME="EDMTDEV Channel";
private NotificationManager manager;

public  NotificationHelper(Context base)
{
    super(base);
    createChannels();
}
private void createChannels()
{
    NotificationChannel edmtChannel=new NotificationChannel(EDMT_CHANNEL_ID,EDMT_CHANNEL_NAME,NotificationManager.IMPORTANCE_DEFAULT);
    edmtChannel.enableLights(true);
    edmtChannel.enableVibration(true);
    edmtChannel.setLightColor(Color.GREEN);
    edmtChannel.setLockscreenVisibility(Notification.VISIBILITY_PRIVATE);

    getManager().createNotificationChannel(edmtChannel);

}
public NotificationManager getManager()
{
   if (manager==null)
       manager=(NotificationManager)getSystemService(Context.NOTIFICATION_SERVICE);
   return manager;

}
public Notification.Builder getEDMTChannelNotification(String title,String body)
{
    return new Notification.Builder(getApplicationContext(),EDMT_CHANNEL_ID)
            .setContentText(body)
            .setContentTitle(title)
            .setSmallIcon(R.mipmap.ic_launcher_round)
            .setAutoCancel(true);
}

}

在活动xml文件中创建一个按钮，然后在主活动中

protected void onCreate（Bundle savedInstanceState）{

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    helper=new NotificationHelper(this);

    btnSend=(Button)findViewById(R.id.btnSend);

    btnSend.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String title="Title";
            String content="Content";
            Notification.Builder builder=helper.getEDMTChannelNotification(title,content);
            helper.getManager().notify(new Random().nextInt(),builder.build());
        }
    });

}

然后运行您的项目

Answer 6

以下方法将显示通知，启用大文本和冻结（即使在用户滑动后通知也不会被删除）。我们需要NotificationManager服务

public static void showNotificationOngoing(Context context,String title) {
        NotificationManager notificationManager =
                (NotificationManager) context.getSystemService(NOTIFICATION_SERVICE);

        PendingIntent contentIntent = PendingIntent.getActivity(context, 0,
                new Intent(context, MainActivity.class), PendingIntent.FLAG_UPDATE_CURRENT);

        Notification.Builder notificationBuilder = new Notification.Builder(context)
                .setContentTitle(title + DateFormat.getDateTimeInstance().format(new Date()) + ":" + accuracy)
                .setContentText(addressFragments.toString())
                .setSmallIcon(R.mipmap.ic_launcher)
                .setContentIntent(contentIntent)
                .setOngoing(true)
                .setStyle(new Notification.BigTextStyle().bigText(addressFragments.toString()))
                .setAutoCancel(true);
        notificationManager.notify(3, notificationBuilder.build());
}

删除通知的方法

public static void removeNotification(Context context){
    NotificationManager notificationManager =
            (NotificationManager) context.getSystemService(NOTIFICATION_SERVICE);
    notificationManager.cancelAll();
}

来源Link

Answer 7

NotificationCompat.Builder(Context context)

已经弃用了大于或等于android Oreo的版本。您可以将实现更改为使用

NotificationCompat.Builder(Context context, String channelId)

Answer 8

通知通道功能是从Api级别26（在oreo中）添加的。以下代码在我这边工作正常，希望它能帮到你

 private void sendNotification(Context ctx, String title, int notificationNumber, String message, String subtext, Intent intent) {       
        try {

            PendingIntent pendingIntent = PendingIntent.getActivity(ctx, notificationNumber, intent,
                    PendingIntent.FLAG_UPDATE_CURRENT);
            Uri url = null;           
            NotificationCompat.Builder notificationBuilder = null;
            try {
                if (Build.VERSION.SDK_INT >= 26) {

                    try{
                        NotificationManager notificationManager = (NotificationManager)getApplicationContext().getSystemService(Context.NOTIFICATION_SERVICE);
                        notificationManager.deleteNotificationChannel(CHANNEL_ID_1);
                        notificationManager.deleteNotificationChannel(CHANNEL_ID_2);

                        if(!intent.getStringExtra("type").equalsIgnoreCase(""+TYPE_RIDE_REQUEST)){
                            NotificationChannel breaking = new NotificationChannel(CHANNEL_ID_1, CHANNEL_ID_1_NAME, NotificationManager.IMPORTANCE_HIGH);
                            breaking.setShowBadge(false);
                            breaking.enableLights(true);
                            breaking.enableVibration(true);
                            breaking.setLightColor(Color.WHITE);
                            breaking.setVibrationPattern(new long[]{100, 200, 100, 200, 100, 200, 100});
                            breaking.setSound(url,new AudioAttributes.Builder().build());

                            notificationBuilder = new NotificationCompat.Builder(this,CHANNEL_ID_1)
                                    .setSmallIcon(R.mipmap.ic_launcher);
                            notificationManager.createNotificationChannel(breaking);

                        }else{

                            NotificationChannel politics = new NotificationChannel(CHANNEL_ID_2,CHANNEL_ID_2_NAME, NotificationManager.IMPORTANCE_DEFAULT);
                            politics.setShowBadge(false);
                            politics.enableLights(true);
                            politics.enableVibration(true);
                            politics.setLightColor(Color.BLUE);
                            politics.setVibrationPattern(new long[]{100, 200, 100, 200, 100});
                            politics.setSound(url,new AudioAttributes.Builder().build());

                            notificationBuilder = new NotificationCompat.Builder(this,CHANNEL_ID_2)
                                    .setSmallIcon(R.mipmap.ic_launcher);
                            notificationManager.createNotificationChannel(politics);
                        }
                    }catch (Exception e){
                        e.printStackTrace();
                    }

                } else {
                    notificationBuilder = new NotificationCompat.Builder(ctx)
                            .setSmallIcon(R.mipmap.ic_launcher);
                }
            } catch (Exception e) {
                e.printStackTrace();
            }

            if (notificationBuilder == null) {
                notificationBuilder = new NotificationCompat.Builder(ctx)
                        .setSmallIcon(R.mipmap.ic_launcher);
            }


            notificationBuilder.setContentTitle(title);          
            notificationBuilder.setSubText(subtext);
            notificationBuilder.setAutoCancel(true);

            notificationBuilder.setContentIntent(pendingIntent);
            notificationBuilder.setNumber(notificationNumber);
            NotificationManager notificationManager =
                    (NotificationManager) ctx.getSystemService(Context.NOTIFICATION_SERVICE);

            notificationManager.notify(notificationNumber, notificationBuilder.build());

        } catch (Exception e) {
            e.printStackTrace();
        }

    }

Answer 9

fun pushNotification(message: String?, clickAtion: String?) {
        val ii = Intent(clickAtion)
        ii.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP)
        val pendingIntent = PendingIntent.getActivity(this, REQUEST_CODE, ii, PendingIntent.FLAG_ONE_SHOT)

        val soundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION)

        val largIcon = BitmapFactory.decodeResource(applicationContext.resources,
                R.mipmap.ic_launcher)


        val notificationManager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager

        val channelId = "default_channel_id"
        val channelDescription = "Default Channel"
// Since android Oreo notification channel is needed.
//Check if notification channel exists and if not create one
        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
            var notificationChannel = notificationManager.getNotificationChannel(channelId)
            if (notificationChannel != null) {
                val importance = NotificationManager.IMPORTANCE_HIGH //Set the importance level
                notificationChannel = NotificationChannel(channelId, channelDescription, importance)
               // notificationChannel.lightColor = Color.GREEN //Set if it is necesssary
                notificationChannel.enableVibration(true) //Set if it is necesssary
                notificationManager.createNotificationChannel(notificationChannel)


                val noti_builder = NotificationCompat.Builder(this)
                        .setContentTitle("MMH")
                        .setContentText(message)
                        .setSmallIcon(R.drawable.ic_launcher_background)
                        .setChannelId(channelId)
                        .build()
                val random = Random()
                val id = random.nextInt()
                notificationManager.notify(id,noti_builder)

            }

        }
        else
        {
            val notificationBuilder = NotificationCompat.Builder(this)
                    .setSmallIcon(R.mipmap.ic_launcher).setColor(resources.getColor(R.color.colorPrimary))
                    .setVibrate(longArrayOf(200, 200, 0, 0, 0))
                    .setContentTitle(getString(R.string.app_name))

                    .setLargeIcon(largIcon)
                    .setContentText(message)
                    .setAutoCancel(true)
                    .setStyle(NotificationCompat.BigTextStyle().bigText(message))
                    .setSound(soundUri)
                    .setContentIntent(pendingIntent)


            val random = Random()
            val id = random.nextInt()
            notificationManager.notify(id, notificationBuilder.build())

        }



    }

Answer 10

    NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this, "CHANNEL_ID")
            ........

    NotificationManager mNotificationManager =
            (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        CharSequence name = "Hello";// The user-visible name of the channel.
        int importance = NotificationManager.IMPORTANCE_HIGH;
        NotificationChannel mChannel = new NotificationChannel(CHANNEL_ID, name, importance);
        mNotificationManager.createNotificationChannel(mChannel);
    }
    mNotificationManager.notify(notificationId, notificationBuilder.build());

Answer 11

除了this answer之外，您还需要在使用之前创建通知通道。

  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {

      /* Create or update. */
      NotificationChannel channel = new NotificationChannel("my_channel_01",
          "Channel human readable title", 
          NotificationManager.IMPORTANCE_DEFAULT);
      mNotificationManager.createNotificationChannel(channel);
  }

此外，只有在targetSdkVersion为26或更高时才需要使用通道。

如果您使用的是NotificationCompat.Builder，则还需要更新到支持库的beta版本：https://developer.android.com/topic/libraries/support-library/revisions.html#26-0-0-beta2（能够在compat构建器上调用setChannelId）。

请注意，此库更新会将minSdkLevel提升为14。

Answer 12

在这里，我发布一些快速解决方案功能与意图处理

public void showNotification(Context context, String title, String body, Intent intent) {
    NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

    int notificationId = 1;
    String channelId = "channel-01";
    String channelName = "Channel Name";
    int importance = NotificationManager.IMPORTANCE_HIGH;

    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
        NotificationChannel mChannel = new NotificationChannel(
                channelId, channelName, importance);
        notificationManager.createNotificationChannel(mChannel);
    }

    NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(context, channelId)
            .setSmallIcon(R.mipmap.ic_launcher)
            .setContentTitle(title)
            .setContentText(body);

    TaskStackBuilder stackBuilder = TaskStackBuilder.create(context);
    stackBuilder.addNextIntent(intent);
    PendingIntent resultPendingIntent = stackBuilder.getPendingIntent(
            0,
            PendingIntent.FLAG_UPDATE_CURRENT
    );
    mBuilder.setContentIntent(resultPendingIntent);

    notificationManager.notify(notificationId, mBuilder.build());
}

Answer 13

public class MyFirebaseMessagingServices extends FirebaseMessagingService {
    private NotificationChannel mChannel;
    private NotificationManager notifManager;
    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        if (remoteMessage.getData().size() > 0) {
            try {
                JSONObject jsonObject = new JSONObject(remoteMessage.getData());
                displayCustomNotificationForOrders(jsonObject.getString("title"), jsonObject.getString("description"));
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }
    }

    private void displayCustomNotificationForOrders(String title, String description) {
        if (notifManager == null) {
            notifManager = (NotificationManager) getSystemService
                    (Context.NOTIFICATION_SERVICE);
        }
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            NotificationCompat.Builder builder;
            Intent intent = new Intent(this, Dashboard.class);
            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            PendingIntent pendingIntent;
            int importance = NotificationManager.IMPORTANCE_HIGH;
            if (mChannel == null) {
                mChannel = new NotificationChannel
                        ("0", title, importance);
                mChannel.setDescription(description);
                mChannel.enableVibration(true);
                notifManager.createNotificationChannel(mChannel);
            }
            builder = new NotificationCompat.Builder(this, "0");

            intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP |
                    Intent.FLAG_ACTIVITY_SINGLE_TOP);
            pendingIntent = PendingIntent.getActivity(this, 1251, intent, PendingIntent.FLAG_ONE_SHOT);
            builder.setContentTitle(title)  
                    .setSmallIcon(getNotificationIcon()) // required
                    .setContentText(description)  // required
                    .setDefaults(Notification.DEFAULT_ALL)
                    .setAutoCancel(true)
                    .setLargeIcon(BitmapFactory.decodeResource
                            (getResources(), R.mipmap.logo))
                    .setBadgeIconType(R.mipmap.logo)
                    .setContentIntent(pendingIntent)
                    .setSound(RingtoneManager.getDefaultUri
                            (RingtoneManager.TYPE_NOTIFICATION));
            Notification notification = builder.build();
            notifManager.notify(0, notification);
        } else {

            Intent intent = new Intent(this, Dashboard.class);
            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            PendingIntent pendingIntent = null;

            pendingIntent = PendingIntent.getActivity(this, 1251, intent, PendingIntent.FLAG_ONE_SHOT);

            Uri defaultSoundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
            NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this)
                    .setContentTitle(title)
                    .setContentText(description)
                    .setAutoCancel(true)
                    .setColor(ContextCompat.getColor(getBaseContext(), R.color.colorPrimary))
                    .setSound(defaultSoundUri)
                    .setSmallIcon(getNotificationIcon())
                    .setContentIntent(pendingIntent)
                    .setStyle(new NotificationCompat.BigTextStyle().setBigContentTitle(title).bigText(description));

            NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
            notificationManager.notify(1251, notificationBuilder.build());
        }
    }

    private int getNotificationIcon() {
        boolean useWhiteIcon = (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP);
        return useWhiteIcon ? R.mipmap.logo : R.mipmap.logo;
    }
}

Answer 14

适用于Android O的Android Notification演示应用以及较低的API版本。这是GitHub-Demo 1和GitHub-Demo 2上最好的演示应用程序。

Answer 15

试试这个代码：

public class FirebaseMessagingServices extends com.google.firebase.messaging.FirebaseMessagingService {
    private static final String TAG = "MY Channel";
    Bitmap bitmap;

    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        super.onMessageReceived(remoteMessage);
        Utility.printMessage(remoteMessage.getNotification().getBody());

        // Check if message contains a data payload.
        if (remoteMessage.getData().size() > 0) {
            Log.d(TAG, "Message data payload: " + remoteMessage.getData());

            String title = remoteMessage.getData().get("title");
            String body = remoteMessage.getData().get("body");
            String message = remoteMessage.getData().get("message");
            String imageUri = remoteMessage.getData().get("image");
            String msg_id = remoteMessage.getData().get("msg-id");
          

            Log.d(TAG, "1: " + title);
            Log.d(TAG, "2: " + body);
            Log.d(TAG, "3: " + message);
            Log.d(TAG, "4: " + imageUri);
          

            if (imageUri != null)
                bitmap = getBitmapfromUrl(imageUri);

            }

            sendNotification(message, bitmap, title, msg_id);
                    
        }


    }

    private void sendNotification(String message, Bitmap image, String title,String msg_id) {
        int notifyID = 0;
        try {
            notifyID = Integer.parseInt(msg_id);
        } catch (NumberFormatException e) {
            e.printStackTrace();
        }

        String CHANNEL_ID = "my_channel_01";            // The id of the channel.
        Intent intent = new Intent(this, HomeActivity.class);
        intent.putExtra("title", title);
        intent.putExtra("message", message);
        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);


        PendingIntent pendingIntent = PendingIntent.getActivity(this, 0 /* Request code */, intent,
                PendingIntent.FLAG_ONE_SHOT);

        Uri defaultSoundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
        NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this, "01")
                .setContentTitle(title)
                .setSmallIcon(R.mipmap.ic_notification)
                .setStyle(new NotificationCompat.BigTextStyle()
                        .bigText(message))
                .setContentText(message)
                .setAutoCancel(true)
                .setSound(defaultSoundUri)
                .setChannelId(CHANNEL_ID)
                .setContentIntent(pendingIntent);

        if (image != null) {
            notificationBuilder.setStyle(new NotificationCompat.BigPictureStyle()   //Set the Image in Big picture Style with text.
                    .bigPicture(image)
                    .setSummaryText(message)
                    .bigLargeIcon(null));
        }


        NotificationManager notificationManager =
                (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {       // For Oreo and greater than it, we required Notification Channel.
           CharSequence name = "My New Channel";                   // The user-visible name of the channel.
            int importance = NotificationManager.IMPORTANCE_HIGH;

            NotificationChannel channel = new NotificationChannel(CHANNEL_ID,name, importance); //Create Notification Channel
            notificationManager.createNotificationChannel(channel);
        }

        notificationManager.notify(notifyID /* ID of notification */, notificationBuilder.build());
    }

    public Bitmap getBitmapfromUrl(String imageUrl) {     //This method returns the Bitmap from Url;
        try {
            URL url = new URL(imageUrl);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setDoInput(true);
            connection.connect();
            InputStream input = connection.getInputStream();
            Bitmap bitmap = BitmapFactory.decodeStream(input);
            return bitmap;

        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return null;

        }

    }

}

Answer 16

如果您无法在26+ SDK版本中获得推送通知？

你的解决方案在这里：

public static void showNotification(Context context, String title, String messageBody) {

        boolean isLoggedIn = SessionManager.getInstance().isLoggedIn();
        Log.e(TAG, "User logged in state: " + isLoggedIn);

        Intent intent = null;
        if (isLoggedIn) {
            //goto notification screen
            intent = new Intent(context, MainActivity.class);
            intent.putExtra(Extras.EXTRA_JUMP_TO, DrawerItems.ITEM_NOTIFICATION);
        } else {
            //goto login screen
            intent = new Intent(context, LandingActivity.class);
        }

        intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        PendingIntent pendingIntent = PendingIntent.getActivity(context, 0 /* Request code */, intent, PendingIntent.FLAG_ONE_SHOT);

        //Uri defaultSoundUri= RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
        //Bitmap largeIcon = BitmapFactory.decodeResource(getResources(), R.drawable.ic_app_notification_icon);

        String channel_id = createNotificationChannel(context);

        NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(context, channel_id)
                .setContentTitle(title)
                .setContentText(messageBody)
                .setStyle(new NotificationCompat.BigTextStyle().bigText(messageBody))
                /*.setLargeIcon(largeIcon)*/
                .setSmallIcon(R.drawable.app_logo_color) //needs white icon with transparent BG (For all platforms)
                .setColor(ContextCompat.getColor(context, R.color.colorPrimaryDark))
                .setVibrate(new long[]{1000, 1000})
                .setSound(Settings.System.DEFAULT_NOTIFICATION_URI)
                .setContentIntent(pendingIntent)
                .setPriority(Notification.PRIORITY_HIGH)
                .setAutoCancel(true);

        NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
        notificationManager.notify((int) ((new Date(System.currentTimeMillis()).getTime() / 1000L) % Integer.MAX_VALUE) /* ID of notification */, notificationBuilder.build());
    }

public static String createNotificationChannel(Context context) {

        // NotificationChannels are required for Notifications on O (API 26) and above.
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {

            // The id of the channel.
            String channelId = "Channel_id";

            // The user-visible name of the channel.
            CharSequence channelName = "Application_name";
            // The user-visible description of the channel.
            String channelDescription = "Application_name Alert";
            int channelImportance = NotificationManager.IMPORTANCE_DEFAULT;
            boolean channelEnableVibrate = true;
//            int channelLockscreenVisibility = Notification.;

            // Initializes NotificationChannel.
            NotificationChannel notificationChannel = new NotificationChannel(channelId, channelName, channelImportance);
            notificationChannel.setDescription(channelDescription);
            notificationChannel.enableVibration(channelEnableVibrate);
//            notificationChannel.setLockscreenVisibility(channelLockscreenVisibility);

            // Adds NotificationChannel to system. Attempting to create an existing notification
            // channel with its original values performs no operation, so it's safe to perform the
            // below sequence.
            NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
            assert notificationManager != null;
            notificationManager.createNotificationChannel(notificationChannel);

            return channelId;
        } else {
            // Returns null for pre-O (26) devices.
            return null;
        }
    }

NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder（context，channel_id）

- >在这里，您将在您的设备中使用channel_id获取推送通知，其中包含26+ SDK版本。

- >因为，NotificationCompat.Builder(context)是不推荐使用的方法，现在你将使用一个更新版本，它有两个参数，一个是上下文，另一个是channel_id。

- > NotificationCompat.Builder(context, channel_id)更新方法。试试吧。

- >在26+ SDK版本的设备中，您每次都会创建channel_id。

Answer 17

这是firebase api版本11.8.0中的错误，因此，如果您减少API版本，您将不会遇到此问题。

Answer 18

将此类用于Android 8通知

public class NotificationHelper {

private Context mContext;
private NotificationManager mNotificationManager;
private NotificationCompat.Builder mBuilder;
public static final String NOTIFICATION_CHANNEL_ID = "10001";

public NotificationHelper(Context context) {
    mContext = context;
}

/**
 * Create and push the notification 
 */
public void createNotification(String title, String message)
{    
    /**Creates an explicit intent for an Activity in your app**/
    Intent resultIntent = new Intent(mContext , SomeOtherActivity.class);
    resultIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

    PendingIntent resultPendingIntent = PendingIntent.getActivity(mContext,
            0 /* Request code */, resultIntent,
            PendingIntent.FLAG_UPDATE_CURRENT);

    mBuilder = new NotificationCompat.Builder(mContext);
    mBuilder.setSmallIcon(R.mipmap.ic_launcher);
    mBuilder.setContentTitle(title)
            .setContentText(message)
            .setAutoCancel(false)
            .setSound(Settings.System.DEFAULT_NOTIFICATION_URI)
            .setContentIntent(resultPendingIntent);

    mNotificationManager = (NotificationManager) mContext.getSystemService(Context.NOTIFICATION_SERVICE);

    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O)
    {
        int importance = NotificationManager.IMPORTANCE_HIGH;
        NotificationChannel notificationChannel = new NotificationChannel(NOTIFICATION_CHANNEL_ID, "NOTIFICATION_CHANNEL_NAME", importance);
        notificationChannel.enableLights(true);
        notificationChannel.setLightColor(Color.RED);
        notificationChannel.enableVibration(true);
        notificationChannel.setVibrationPattern(new long[]{100, 200, 300, 400, 500, 400, 300, 200, 400});
        assert mNotificationManager != null;
        mBuilder.setChannelId(NOTIFICATION_CHANNEL_ID);
        mNotificationManager.createNotificationChannel(notificationChannel);
    }
    assert mNotificationManager != null;
    mNotificationManager.notify(0 /* Request Code */, mBuilder.build());
  }
}