要求通知权限可以通过以下步骤实现：

1. 在您的AndroidManifest.xml文件中添加以下代码，以请求通知权限：

2. 在您的应用程序代码中，使用以下代码请求通知许可：

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    NotificationChannel channel = new NotificationChannel(CHANNEL_ID, "Channel human readable title", NotificationManager.IMPORTANCE_DEFAULT);
    notificationManager.createNotificationChannel(channel);
}

NotificationCompat.Builder builder = new NotificationCompat.Builder(this, CHANNEL_ID)
        .setSmallIcon(R.drawable.icon)
        .setContentTitle("My notification title")
        .setContentText("Hello World!")
        .setPriority(NotificationCompat.PRIORITY_DEFAULT);

// Show the notification
notificationManager.notify(notificationId, builder.build());

3. 最后，要确保在用户打开应用程序时请求通知权限：

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    // Create channel to show notifications.
    String channelId = getString(R.string.default_notification_channel_id);
    String channelName = getString(R.string.default_notification_channel_name);
    notificationManager.createNotificationChannel(new NotificationChannel(channelId, channelName, NotificationManager.IMPORTANCE_HIGH));
}

// Notice that the id passed in is 0, it can be any integer you want,
// this is just your unique id for your notification
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
    NotificationChannel channel = notificationManager.getNotificationChannel(getString(R.string.default_notification_channel_id));
    if(channel.getImportance() == NotificationManager.IMPORTANCE_NONE) {
        Intent intent = new Intent(Settings.ACTION_CHANNEL_NOTIFICATION_SETTINGS);
        intent.putExtra(Settings.EXTRA_APP_PACKAGE, getPackageName());
        intent.putExtra(Settings.EXTRA_CHANNEL_ID, channel