使用AlarmManager更新应用小部件

Question

我试图比1.6docs施加的30分钟限制更频繁地更新Widget.在阅读了SO中的几乎所有帖子,以及开发人员文档和其他各种来源之后,我认为我已经达到了可以实现它的程度.所以,我尝试过,但失败了.从那时起,我已经搜索了更多的论坛和解决方案,我似乎无法更新它.

我有一个Update类来设置AlarmManager:

public class Update extends Service{

    @Override
    public void onStart(Intent intent, int startId) {
          String currentTemp = Battery.outputTemp;
          String currentLevel = Battery.outputLevel;
          String currentCard = Battery.outputCard;
          String currentInternal = Battery.memory;
          String currentRam = String.valueOf(Battery.outputRam).substring(0, 3) + "MB";

          // Change the text in the widget
          RemoteViews updateViews = new RemoteViews( 
          this.getPackageName(), R.layout.main);
          //update temp
          updateViews.setTextViewText(R.id.batteryTemp, currentTemp); 
          //update %
          updateViews.setTextViewText(R.id.batteryLevel, currentLevel);     
          //update level
          updateViews.setTextViewText(R.id.sdCard, currentCard);
          //update internal memory
          updateViews.setTextViewText(R.id.internal, currentInternal);
          //update ram
          updateViews.setTextViewText(R.id.ram, currentRam);

          ComponentName thisWidget = new ComponentName(this, Widget.class);
          AppWidgetManager manager = AppWidgetManager.getInstance(this);
          manager.updateAppWidget(thisWidget, updateViews);

    }
    @Override
    public IBinder onBind(Intent intent) {
        // no need to bind
        return null;
    }

}

这导致我的widget类中的onReceive经常触发(我有一个toast来查看它何时触发),但它没有意图(toast意味着显示它,因为它们被收到但是它是空白的).

我无法弄清楚(我是一个相对较新的2个月的慢速Android开发者),并欣赏你们有任何洞察力.

继承我的widget类供参考:

    public class Widget extends AppWidgetProvider {


    @Override
    public void onUpdate(Context context, AppWidgetManager appWidgetManager,
            int[] appWidgetIds) {

        AlarmManager alarmManager;
        Intent intent = new Intent(context, Update.class);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0,
                intent, PendingIntent.FLAG_UPDATE_CURRENT);
        alarmManager = (AlarmManager) context
                .getSystemService(Context.ALARM_SERVICE);
        Calendar cal = Calendar.getInstance();
        cal.setTimeInMillis(System.currentTimeMillis());
        cal.add(Calendar.SECOND, 10);
        alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, cal
                .getTimeInMillis(), 5 * 1000, pendingIntent);

        String currentTemp = Battery.outputTemp;
        String currentLevel = Battery.outputLevel;
        String currentCard = Battery.outputCard;
        String currentInternal = Battery.memory;
        String currentRam = String.valueOf(Battery.outputRam).substring(0, 3)
                + "MB";

        // Change the text in the widget
        RemoteViews updateViews = new RemoteViews(context.getPackageName(),
                R.layout.main);
        // update temp
        updateViews.setTextViewText(R.id.batteryTemp, currentTemp);
        appWidgetManager.updateAppWidget(appWidgetIds, updateViews);
        // update %
        updateViews.setTextViewText(R.id.batteryLevel, currentLevel);
        appWidgetManager.updateAppWidget(appWidgetIds, updateViews);
        // update level
        updateViews.setTextViewText(R.id.sdCard, currentCard);
        appWidgetManager.updateAppWidget(appWidgetIds, updateViews);
        // update internal memory
        updateViews.setTextViewText(R.id.internal, currentInternal);
        appWidgetManager.updateAppWidget(appWidgetIds, updateViews);
        // update ram
        updateViews.setTextViewText(R.id.ram, currentRam);
        appWidgetManager.updateAppWidget(appWidgetIds, updateViews);
        super.onUpdate(context, appWidgetManager, appWidgetIds);

    }

    public void onReceive(Context context, Intent intent) {

        super.onReceive(context, intent);
        Toast
                .makeText(context, intent.getAction() + context,
                        Toast.LENGTH_LONG).show();
        Bundle extras = intent.getExtras();
        if (extras != null) {
            AppWidgetManager appWidgetManager = AppWidgetManager
                    .getInstance(context);
            ComponentName thisAppWidget = new ComponentName(context
                    .getPackageName(), Widget.class.getName());
            int[] appWidgetIds = appWidgetManager
                    .getAppWidgetIds(thisAppWidget);

            onUpdate(context, appWidgetManager, appWidgetIds);
        }

    }
}

Answer 1

这是我的解决方案,如何比30分钟更频繁地自动更新小部件.我使用AlarmManager.在使用AlarmManager刷新appwidget之前,请确保您知道自己在做什么,因为这种技术可能会耗尽设备的电量.

阅读有关Android文档中小部件更新的更多信息- 尤其是有关updatePeriodMillis参数的信息.

这是我的Manifest.xml的一部分.我定义自定义操作AUTO_UPDATE.

<receiver android:name=".appwidget.AppWidget" >
    <intent-filter>
        <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
    </intent-filter>
    <intent-filter>
        <action android:name="AUTO_UPDATE" />
    </intent-filter>
    <meta-data android:name="android.appwidget.provider" android:resource="@xml/appwidget_info" />
</receiver>

这是我的AppWidget.java的一部分.在onReceive方法中,我处理自定义操作AUTO_UPDATE.在onEnabled和onDisabled方法中,我启动/停止警报.

public class AppWidget extends AppWidgetProvider
{
    public static final String ACTION_AUTO_UPDATE = "AUTO_UPDATE";

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

        if(intent.getAction().equals(ACTION_AUTO_UPDATE))
        {
            // DO SOMETHING
        }

        ...
    }

    @Override
    public void onEnabled(Context context)
    {
        // start alarm
        AppWidgetAlarm appWidgetAlarm = new AppWidgetAlarm(context.getApplicationContext());
        appWidgetAlarm.startAlarm();
    }

    @Override
    public void onDisabled(Context context)
    {
        // stop alarm only if all widgets have been disabled
        AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
        ComponentName thisAppWidgetComponentName = new ComponentName(context.getPackageName(),getClass().getName());
        int[] appWidgetIds = appWidgetManager.getAppWidgetIds(thisAppWidgetComponentName);
        if (appWidgetIds.length == 0) {
            // stop alarm
            AppWidgetAlarm appWidgetAlarm = new AppWidgetAlarm(context.getApplicationContext());
            appWidgetAlarm.stopAlarm();
    }

    }

    ...
}

这是我的AppWidgetAlarm.java,它启动/停止警报.警报管理器向AppWidget发送广播.

public class AppWidgetAlarm
{
    private final int ALARM_ID = 0;
    private final int INTERVAL_MILLIS = 10000;

    private Context mContext;


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


    public void startAlarm()
    {
        Calendar calendar = Calendar.getInstance();
        calendar.add(Calendar.MILLISECOND, INTERVAL_MILLIS);

        Intent alarmIntent = new Intent(AppWidget.ACTION_AUTO_UPDATE);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(mContext, ALARM_ID, alarmIntent, PendingIntent.FLAG_CANCEL_CURRENT);

        AlarmManager alarmManager = (AlarmManager) mContext.getSystemService(Context.ALARM_SERVICE);
        // RTC does not wake the device up
        alarmManager.setRepeating(AlarmManager.RTC, calendar.getTimeInMillis(), INTERVAL_MILLIS, pendingIntent);
    }


    public void stopAlarm()
    {
        Intent alarmIntent = new Intent(AppWidget.ACTION_AUTO_UPDATE);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(mContext, ALARM_ID, alarmIntent, PendingIntent.FLAG_CANCEL_CURRENT);

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

Answer 2

我有一个Update类来设置AlarmManager:

不,你没有.AlarmManager在代码段中没有出现.

您确实AlarmManager在第二个代码段中有引用.问题包括:

• 每次应用小部件更新时,您都要设置新的重复警报

• 你在闹钟上设置了5秒的频率,这完全是疯狂的

• 你在_WAKEUP警报上设置了5秒的频率,我认为这是你在某些司法管辖区被捕的理由

• 你有一个毫无意义的onReceive()方法,甚至忽略了临时的方法Toast

• 我们假定你是会有的动作串Intent在你Toast,但是当你创建你不指定操作字符串Intent,你放在PendingIntent了报警

• 你的代码指的是我认为是Battery类中的静态数据成员,但很可能那些都是空的/ null ...或者至少它们会是,如果你有一个合理的报警频率