即使在应用程序关闭时也能监听时区变化

Question

即使我的 Android 应用关闭，我也会尝试监听时区变化。

我尝试了什么：

1. 我为它找到了一个意图操作。现在是 TIME_ZONE_CHANGED。然而它 是一个受保护的意图，只能由系统作为 文档说，而且它可能不允许这样做 隐式广播。

2. 我尝试了 AlarmManager，但找不到确切的时区更改 事件。

3. 我在应用服务的线程中使用了schedululeAtFixedRate。它工作得很好。 但我不想让它听每小时的变化，我只想要时区时区的变化，就像我上面提到的那样。

---

编辑：

MainActivity

public static final String CHANNEL_ID = "49";

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    createNotificationChannel();
    startService(new Intent(this,AppService.class));
}

 private void createNotificationChannel() {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        CharSequence c_name = getString(R.string.notification_channel_name);
        String c_desc = getString(R.string.notification_channel_description);
        int importance = NotificationManager.IMPORTANCE_DEFAULT;
        NotificationChannel notificationChannel = new NotificationChannel(CHANNEL_ID,c_name,importance);
        notificationChannel.setDescription(c_desc);
        NotificationManager manager = getSystemService(NotificationManager.class);
        manager.createNotificationChannel(notificationChannel);
    }
}

清单

<?xml version="1.0" encoding="utf-8"?>

<uses-permission android:name="android.permission.INTERNET" />
<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"
    android:usesCleartextTraffic="true">
    <receiver
        android:name=".TimeChangedReceiver"
        android:enabled="true"
        android:exported="true">

        <intent-filter >
            <action android:name="android.intent.action.TIMEZONE_CHANGED"/>
        </intent-filter>

    </receiver>

    <service
        android:name=".AppService"
        android:enabled="true"
        android:exported="true" />

    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

接收者类

package com.example.gridview;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;

import androidx.core.app.NotificationCompat;
import androidx.core.app.NotificationManagerCompat;

public class TimeChangedReceiver extends BroadcastReceiver {

private static int NOTIFICATION_ID = 1;

@Override
public void onReceive(Context context, Intent intent) {
    // TODO: This method is called when the BroadcastReceiver is receiving
    // an Intent broadcast.
    StringBuilder sb = new StringBuilder("Timezone is changed 
    YAY!,executed for "+NOTIFICATION_ID+" times.");
    if (intent.getAction().equals(Intent.ACTION_TIMEZONE_CHANGED)) {
        sb.append("\n Status: Ok.");
    }
  
    NotificationCompat.Builder builder = new 
    NotificationCompat.Builder(context,MainActivity.CHANNEL_ID)
            .setPriority(NotificationCompat.PRIORITY_DEFAULT)
            .setContentText(sb.toString())
            .setSmallIcon(R.drawable.ic_launcher_background)
            .setContentTitle("Hey!");
    NotificationManagerCompat notificationManager = 
    NotificationManagerCompat.from(context);
    notificationManager.notify(NOTIFICATION_ID,builder.build());
    NOTIFICATION_ID++;
}

}

Answer 1

您应该为"android.intent.action.TIMEZONE_CHANGED"（又名Intent.ACTION_TIMEZONE_CHANGED）注册一个清单接收器。是implicit broadcast exceptions之一，不受Android 8.0+注册清单接收器的限制。

当您的应用未运行时，这样的清单接收器将是检测此类事件的唯一方法。