Android 报警管理器工作不正常，通知无效'；我没有出现

所以我有两个类来构建通知，由于某种原因，它们都没有显示任何通知，尽管没有发现错误

我有

将接收器设置为

AndroidManifest.xml

在生成器上使用setsmallicon

在MainActivity上运行它

这是第一个类

NotificationHelper

，它创建通道并执行大部分通知样板代码

import android.annotation.TargetApi;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.content.Context;
import android.content.ContextWrapper;
import android.os.Build;
import android.support.v4.app.NotificationCompat;


public class NotificationHelper extends ContextWrapper {

public static String CHANNEL_ID = "channel_01";
public static CharSequence CHANNEL_NAME = "dicoding channel";
private NotificationManager notificationManager;
NotificationChannel channel;

public NotificationHelper(Context base) {
    super(base);
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        createChannels();
    }
}

@TargetApi(Build.VERSION_CODES.O)
public void createChannels() {

    channel = new NotificationChannel(CHANNEL_ID,
            CHANNEL_NAME,
            NotificationManager.IMPORTANCE_DEFAULT);
    channel.enableVibration(true);
    channel.enableLights(true);
    channel.setLockscreenVisibility(MODE_PRIVATE);

    if (notificationManager != null) {
        getNotificationManager().createNotificationChannel(channel);
    }
}

public NotificationManager getNotificationManager() {
    if (notificationManager == null) {
        notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
    }
    return notificationManager;
}

public NotificationCompat.Builder getChannelNotification() {
    return new NotificationCompat.Builder(getApplicationContext(), CHANNEL_ID)
            .setContentTitle("Film Tv")
            .setContentText("Hey, cek katalog movie kamu sekarang!")
            .setSmallIcon(android.R.drawable.sym_def_app_icon);

}

}

以及receiver类

AlertReceiver

，它扩展了BroadcastReceiver以构建通知

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.support.v4.app.NotificationCompat;


public class AlertReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
    NotificationHelper notificationHelper = new NotificationHelper(context);
    NotificationCompat.Builder nb = notificationHelper.getChannelNotification();
    notificationHelper.getNotificationManager().notify(1, nb.build());


 }
}

这是包含

BottomNavigation

的主要活动，因此我将其称为

BottomNavigation

，您应该在其中放置通知。但奇怪的是，只有底部导航加载，而没有通知

import android.annotation.TargetApi;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.provider.Settings;
import android.support.design.widget.BottomNavigationView;
import android.support.v4.app.Fragment;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;

import java.util.Calendar;

. . . . . .. . . . . . ..

public class BottomNavigation extends AppCompatActivity {


BottomNavigationView navView;
Toolbar toolbar;
private String title;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.bottom_navigation);
    navView = findViewById(R.id.nav_view);
    toolbar = findViewById(R.id.toolbar);

    // placing toolbar in place of action bar
    setSupportActionBar(toolbar);

    startAlarm();
    bottomNavigation();

    . . . . . . . . . . .  . . . . . . .

}

@TargetApi(Build.VERSION_CODES.KITKAT)
private void startAlarm() {
    Calendar c = Calendar.getInstance();
    AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
    Intent intent = new Intent(this, AlertReceiver.class);
    PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 1, intent, 0);

    c.set(Calendar.HOUR_OF_DAY, 20);
    c.set(Calendar.MINUTE, 27);
    c.set(Calendar.SECOND, 30);

    alarmManager.setExact(AlarmManager.RTC_WAKEUP, c.getTimeInMillis(), pendingIntent);
}

底部导航显示，所有内容都加载，只有通知不会显示。这款手机是搭载安卓28的诺基亚6.1。为什么通知不显示？

在

onReceive（）

中，尝试将

getNotificationManager（）

替换为

notificationmanager compat.from（context）

如果这样做有效，您可以修改

getNotificationManager（）

并重新使用它

---

如果它不起作用，请将

startAlarm（）

替换为

onReceive（）

中的代码，以帮助找出问题是出在警报还是通知上。

尝试将

getNotificationManager（）

替换为

notificationmanager compat.from（上下文）时，会显示一条红色文本

在接收时将

startAlarm

中的代码替换为

onReceive

中的代码，并且通知没有显示是

导入android.support.v4.app.NotificationCompat

可能吗？如何使用

NotificationManager.compat

构建频道？尝试替换

getNotificationManager

返回

NotificationManager.compat

，通知和生成是否仍不显示

import android.annotation.TargetApi;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.provider.Settings;
import android.support.design.widget.BottomNavigationView;
import android.support.v4.app.Fragment;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;

import java.util.Calendar;

. . . . . .. . . . . . ..

public class BottomNavigation extends AppCompatActivity {


BottomNavigationView navView;
Toolbar toolbar;
private String title;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.bottom_navigation);
    navView = findViewById(R.id.nav_view);
    toolbar = findViewById(R.id.toolbar);

    // placing toolbar in place of action bar
    setSupportActionBar(toolbar);

    startAlarm();
    bottomNavigation();

    . . . . . . . . . . .  . . . . . . .

}

@TargetApi(Build.VERSION_CODES.KITKAT)
private void startAlarm() {
    Calendar c = Calendar.getInstance();
    AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
    Intent intent = new Intent(this, AlertReceiver.class);
    PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 1, intent, 0);

    c.set(Calendar.HOUR_OF_DAY, 20);
    c.set(Calendar.MINUTE, 27);
    c.set(Calendar.SECOND, 30);

    alarmManager.setExact(AlarmManager.RTC_WAKEUP, c.getTimeInMillis(), pendingIntent);
}