Question

我的通知会显示在自定义时间和日期中，一切正常，但当应用关闭时，通知不再显示。我已经使用AlarmManager在特定时间显示通知。

MainActivity.java

import android.app.AlarmManager;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.media.RingtoneManager;
import android.support.v4.app.NotificationCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import java.util.Calendar;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        AlarmManager alarmManager=(AlarmManager)this.getSystemService(Context.ALARM_SERVICE);
        Receiver receiver=new Receiver();
        IntentFilter intentFilter=new IntentFilter("ALARM_ACTION");
        registerReceiver(receiver, intentFilter);
        Intent intent = new Intent("ALARM_ACTION");
        intent.putExtra("param", "My scheduled action");
        PendingIntent operation = PendingIntent.getBroadcast(this, 0, intent, 0);

        Calendar calendar=Calendar.getInstance();
        calendar.setTimeInMillis(System.currentTimeMillis());
        calendar.clear();
        calendar.set(Calendar.DATE,26);
        calendar.set(Calendar.MONTH,Calendar.MARCH);
        calendar.set(Calendar.YEAR,2018);
        calendar.set(Calendar.HOUR_OF_DAY, 16);
        calendar.set(Calendar.MINUTE, 52);
        calendar.set(Calendar.SECOND, 0);

        alarmManager.set(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), operation) ;
    }

    private void addNotification() {
        Intent intent = new Intent(this, SecondActivity.class);
        PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);

        NotificationCompat.Builder builder = new NotificationCompat.Builder(this, "ChannelID");
        builder.setSmallIcon(R.drawable.ic_launcher_background);
        builder.setContentTitle("Notifications Example");
        builder.setContentText("This is a test notification");
        builder.setContentIntent(pendingIntent);
        builder.setSound(RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION));
        builder.setAutoCancel(true);

        NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
        notificationManager.notify(0, builder.build());
    }

    public class Receiver extends BroadcastReceiver{

        @Override
        public void onReceive(Context context, Intent intent) {
            addNotification();
        }
    }
}

和 AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.arantik.test">

    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <receiver
            android:name=".Receiver"
            android:enabled="true"
            android:exported="true"
            android:label="StartMyServiceAtBootReceiver">
            <intent-filter>
                <action android:name="android.intent.action.BOOT_COMPLETED" />
            </intent-filter>
        </receiver>

        <activity android:name=".SecondActivity"></activity>

    </application>

</manifest>

Answer 1

请勿从您的活动中调用registerReceiver（），当您关闭应用时，接收器将会死亡。您需要在Manifest中声明接收器。 并将接收器用作独立类而不是内部类。 AlarmManager将使用PendingIntent数据调用接收器。像这样设置你的PendingIntent并将以下方法添加到你的Activity中并从onCreate中调用它，如下所示：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    AlarmManager alarmManager=(AlarmManager)this.getSystemService(Context.ALARM_SERVICE);

    Intent alarmIntent = new Intent(getApplicationContext(), YourReceiver.class);
    PendingIntent operation = PendingIntent.getBroadcast(getApplicationContext(), 0, alarmIntent, PendingIntent.FLAG_UPDATE_CURRENT);

    Calendar calendar=Calendar.getInstance();
    calendar.setTimeInMillis(System.currentTimeMillis());
    calendar.clear();
    calendar.set(Calendar.DATE,26);
    calendar.set(Calendar.MONTH,Calendar.MARCH);
    calendar.set(Calendar.YEAR,2018);
    calendar.set(Calendar.HOUR_OF_DAY, 16);
    calendar.set(Calendar.MINUTE, 52);
    calendar.set(Calendar.SECOND, 0);

    registerOneTimeAlarm(operation, calendar.getTimeInMillis());
}

private void registerOneTimeAlarm(PendingIntent alarmIntent, long when) {
    int SDK_INT = Build.VERSION.SDK_INT;
    if (SDK_INT < Build.VERSION_CODES.KITKAT) {
        alarmManager.set(AlarmManager.RTC_WAKEUP, when, alarmIntent);
    } else if (Build.VERSION_CODES.KITKAT <= SDK_INT && SDK_INT < Build.VERSION_CODES.M) {
        alarmManager.setExact(AlarmManager.RTC_WAKEUP, when, alarmIntent);
    } else if (SDK_INT >= Build.VERSION_CODES.M) {
        alarmManager.setExactAndAllowWhileIdle(AlarmManager.RTC_WAKEUP, when, alarmIntent);
    }
}

此方法更好地支持新的Android限制。

将接收器添加到您的Manifest中，以便可以明确触发：

<receiver
        android:name=".YourReceiver"
        android:enabled="true"
        />

将addNotification（）方法放在接收器类中，或者启动一个将调用此方法的服务，这不是一个长操作，所以我只是把它放在接收器中。

关闭应用后，我的通知无法显示

1 个答案: