我难住了。我知道这个问题已经被回答了一百次，但我没有尝试过任何工作。

我的问题:我制作了一个需要刷新的 Android 小部件 正是每分钟，就像所有时钟小部件一样。 (这个小部件告诉我在我的火车离开前还剩多少分钟，一分钟的错误使它无用)。

以下是我的尝试，以及各自的结果:

AlarmManager am = (AlarmManager)context.getSystemService
        (Context.ALARM_SERVICE);
Calendar calendar = Calendar.getInstance();
long now = System.currentTimeMillis();
// start at the next minute
calendar.setTimeInMillis(now + 60000 - (now % 60000));
am.setRepeating(AlarmManager.RTC, calendar.getTimeInMillis(), 60000,
        createUpdateIntent(context));

Calendar calendar = Calendar.getInstance();
long now = System.currentTimeMillis();
long delta = 60000 - (now % 60000);

Log.d(LOG_TAG, "Scheduling another update in "+ (delta/1000) +" seconds");
calendar.setTimeInMillis(now + delta);
AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
alarmManager.setExact(AlarmManager.RTC, calendar.getTimeInMillis(), //UPDATE_PERIOD_SECONDS * 1000,
        createUpdateIntent(context));

int delay = (int)(60000 - (System.currentTimeMillis() % 60000));
Log.d(LOG_TAG, "Scheduling another update in " + delay/1000 + " seconds");
new Handler().postDelayed(new Runnable() {
    public void run() {
        Log.d(LOG_TAG, "Scheduled update running");
        updateAppWidget();
    }
}, delay);

最佳答案

对不起，我完全忘记了，很忙.. 好吧，我希望你知道你需要什么，下面是 fragment ，希望我没有忘记什么。

在小部件提供程序类上。

public static final String ACTION_TICK = "CLOCK_TICK";
public static final String SETTINGS_CHANGED = "SETTINGS_CHANGED";
public static final String JOB_TICK = "JOB_CLOCK_TICK";

 @Override
    public void onReceive(Context context, Intent intent){
        super.onReceive(context, intent);

        preferences =  PreferenceManager.getDefaultSharedPreferences(context);

        AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
        ComponentName thisAppWidget = new ComponentName(context.getPackageName(), WidgetProvider.class.getName());
        int[] appWidgetIds = appWidgetManager.getAppWidgetIds(thisAppWidget);

        if (intent.getAction().equals(SETTINGS_CHANGED)) {
            onUpdate(context, appWidgetManager, appWidgetIds);
            if (appWidgetIds.length > 0) {
                restartAll(context);
            }
        }

        if (intent.getAction().equals(JOB_TICK) || intent.getAction().equals(ACTION_TICK) ||
                intent.getAction().equals(AppWidgetManager.ACTION_APPWIDGET_UPDATE)
                || intent.getAction().equals(Intent.ACTION_DATE_CHANGED)
                || intent.getAction().equals(Intent.ACTION_TIME_CHANGED)
                || intent.getAction().equals(Intent.ACTION_TIMEZONE_CHANGED)) {
            restartAll(context);
            onUpdate(context, appWidgetManager, appWidgetIds);
        }
    }

private void restartAll(Context context){
        Intent serviceBG = new Intent(context.getApplicationContext(), WidgetBackgroundService.class);
        context.getApplicationContext().startService(serviceBG);
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            scheduleJob(context);
        } else {
            AppWidgetAlarm appWidgetAlarm = new AppWidgetAlarm(context.getApplicationContext());
            appWidgetAlarm.startAlarm();
        }
    }



 @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    private void scheduleJob(Context context) {
        ComponentName serviceComponent = new ComponentName(context.getPackageName(), RepeatingJob.class.getName());
        JobInfo.Builder builder = new JobInfo.Builder(0, serviceComponent);
        builder.setPersisted(true);
        builder.setPeriodic(600000);
        JobScheduler jobScheduler = (JobScheduler) context.getSystemService(Context.JOB_SCHEDULER_SERVICE);
        int jobResult = jobScheduler.schedule(builder.build());
        if (jobResult == JobScheduler.RESULT_SUCCESS){
        }
    }


    @Override
    public void onEnabled(Context context){

        restartAll(context);
    }


    @Override
    public void onDisabled(Context context){

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            JobScheduler jobScheduler = (JobScheduler) context.getSystemService(Context.JOB_SCHEDULER_SERVICE);
            jobScheduler.cancelAll();
        } else {
            // stop alarm
            AppWidgetAlarm appWidgetAlarm = new AppWidgetAlarm(context.getApplicationContext());
            appWidgetAlarm.stopAlarm();
        }

        Intent serviceBG = new Intent(context.getApplicationContext(), WidgetBackgroundService.class);
        serviceBG.putExtra("SHUTDOWN", true);
        context.getApplicationContext().startService(serviceBG);
        context.getApplicationContext().stopService(serviceBG);
    }

public class WidgetBackgroundService extends Service {

        private static final String TAG = "WidgetBackground";
        private static BroadcastReceiver mMinuteTickReceiver;

        @Override
        public IBinder onBind(Intent arg0){
            return null;
        }

        @Override
        public void onCreate(){
            super.onCreate();
        }



        @Override
        public int onStartCommand(Intent intent, int flags, int startId) {
            if(intent != null) {
                if (intent.hasExtra("SHUTDOWN")) {
                    if (intent.getBooleanExtra("SHUTDOWN", false)) {

                        if(mMinuteTickReceiver!=null) {
                            unregisterReceiver(mMinuteTickReceiver);
                            mMinuteTickReceiver = null;
                        }
                        stopSelf();
                        return START_NOT_STICKY;
                    }
                }
            }

            if(mMinuteTickReceiver==null) {
                registerOnTickReceiver();
            }
            // We want this service to continue running until it is explicitly
            // stopped, so return sticky.
            return START_STICKY;
        }

        @Override
        public void onDestroy(){
            if(mMinuteTickReceiver!=null) {
                unregisterReceiver(mMinuteTickReceiver);
                mMinuteTickReceiver = null;
            }

            super.onDestroy();
        }

        private void registerOnTickReceiver() {
            mMinuteTickReceiver = new BroadcastReceiver(){
                @Override
                public void onReceive(Context context, Intent intent){
                    Intent timeTick=new Intent(WidgetProvider.ACTION_TICK);
                    sendBroadcast(timeTick);
                }
            };
            IntentFilter filter = new IntentFilter();
            filter.addAction(Intent.ACTION_TIME_TICK);
            filter.addAction(Intent.ACTION_SCREEN_ON);
            registerReceiver(mMinuteTickReceiver, filter);
        }
}

@TargetApi(Build.VERSION_CODES.LOLLIPOP)
public class RepeatingJob extends JobService {
    private final static String TAG = "RepeatingJob";

    @Override
    public boolean onStartJob(JobParameters params) {
        Log.d(TAG, "onStartJob");
        Intent intent=new Intent(WidgetProvider.JOB_TICK);
        sendBroadcast(intent);
        return false;
    }

    @Override
    public boolean onStopJob(JobParameters params) {
        return false;
    }
}

public class AppWidgetAlarm {
    private static final String TAG = "AppWidgetAlarm";

    private final int ALARM_ID = 0;
    private static final int INTERVAL_MILLIS = 240000;
    private Context mContext;


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


    public void startAlarm() {
        Calendar calendar = Calendar.getInstance();
        calendar.add(Calendar.MILLISECOND, INTERVAL_MILLIS);
        AlarmManager alarmManager = (AlarmManager) mContext.getSystemService(Context.ALARM_SERVICE);
        Intent alarmIntent = new Intent(WidgetProvider.ACTION_TICK);
        PendingIntent removedIntent = PendingIntent.getBroadcast(mContext, ALARM_ID, alarmIntent, PendingIntent.FLAG_CANCEL_CURRENT);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(mContext, ALARM_ID, alarmIntent, PendingIntent.FLAG_CANCEL_CURRENT);
        Log.d(TAG, "StartAlarm");
        alarmManager.cancel(removedIntent);
        // needs RTC_WAKEUP to wake the device
        alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, calendar.getTimeInMillis(), INTERVAL_MILLIS, pendingIntent);
    }

    public void stopAlarm()
    {
        Log.d(TAG, "StopAlarm");

        Intent alarmIntent = new Intent(WidgetProvider.ACTION_TICK);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(mContext, ALARM_ID, alarmIntent, PendingIntent.FLAG_CANCEL_CURRENT);

        AlarmManager alarmManager = (AlarmManager) mContext.getSystemService(Context.ALARM_SERVICE);
        alarmManager.cancel(pendingIntent);
    }
}

<receiver android:name=".services.SlowWidgetProvider" >
    <intent-filter>
        <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
    </intent-filter>
    <intent-filter>
        <action android:name="CLOCK_TICK" />
    </intent-filter>
    <intent-filter>
        <action android:name="JOB_CLOCK_TICK" />
    </intent-filter>
    <intent-filter>
        <action android:name="SETTINGS_CHANGED" />
    </intent-filter>
    <intent-filter>
        <action android:name="android.intent.action.TIME_SET" />
    </intent-filter>
    <intent-filter>
        <action android:name="android.intent.action.TIMEZONE_CHANGED" />
    </intent-filter>
    <intent-filter>
        <action android:name="android.intent.action.DATE_CHANGED" />
    </intent-filter>
    <intent-filter>
        <action android:name="android.os.action.DEVICE_IDLE_MODE_CHANGED"/>
    </intent-filter>
    <intent-filter>
        <action android:name="android.intent.action.ACTION_DREAMING_STOPPED" />
    </intent-filter>
    <meta-data android:name="android.appwidget.provider"
        android:resource="@xml/slow_widget_info" />
</receiver>

<service
    android:name=".services.RepeatingJob"
    android:permission="android.permission.BIND_JOB_SERVICE"
    android:exported="true"/>

<service android:name=".services.WidgetBackgroundService" />

关于android - 如何真正准确地每分钟更新一个小部件，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/38678241/