我想制作一个类似于 Widget 的 CountDown 计时器。我希望它每秒更新一次。下面是我的代码。 onUpdate() 根本不会被调用，除了开始时调用一次。请指出我的问题。提前致谢。

JAVA代码

public class MainActivity extends AppWidgetProvider {

    private boolean isTimeComplete = false;
    private int days, hours, minutes, seconds;
    private PendingIntent pendingIntent;

    @Override
    public void onEnabled(Context context) {
        super.onEnabled(context);

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

        Intent alarm = new Intent(context, MainActivity.class);
        pendingIntent = PendingIntent.getService(context, 0, alarm,
                    PendingIntent.FLAG_CANCEL_CURRENT);
        alarmManager.setRepeating(AlarmManager.RTC, System.currentTimeMillis(),
                1000, pendingIntent);
        ComponentName thisWidget = new ComponentName(context,
                MainActivity.class);
        AppWidgetManager manager = AppWidgetManager.getInstance(context);
        manager.updateAppWidget(thisWidget,
                new RemoteViews(context.getPackageName(),
                        R.layout.activity_main));
        int appWidgetIds[] = manager.getAppWidgetIds(thisWidget);
        manager.notifyAppWidgetViewDataChanged(appWidgetIds, R.id.text_value);

    }

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

        RemoteViews remoteViews = new RemoteViews(context.getPackageName(),
                R.layout.activity_main);
        ComponentName timerWidget = new ComponentName(context,
                MainActivity.class);

        SimpleDateFormat format = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss",
                Locale.US);
        Date d2 = null;
        try {
            d2 = format.parse("2014/10/04 10:00:00");
        } catch (ParseException e) {
            e.printStackTrace();
        }

        Calendar cal = Calendar.getInstance();

        long diff = d2.getTime() - cal.getTime().getTime();
        seconds = (int) (diff / 1000) % 60;
        minutes = (int) ((diff / (1000 * 60)) % 60);
        hours = (int) ((diff / (1000 * 60 * 60)) % 24);
        days = (int) (diff / (1000 * 60 * 60 * 24));
        remoteViews.setTextViewText(R.id.text_remaining,
                context.getString(R.string.time_remaining_text));
        remoteViews.setTextViewText(
        R.id.text_value,
        String.format(context.getString(R.string.text_days),
                days)
        + " "
        + String.format(
        context.getString(R.string.text_hours),
                hours)
        + " "
        + String.format(context.getString(R.string.text_minutes),
                minutes)
        + " "
        + String.format(context.getString(R.string.text_seconds),
                seconds));
        appWidgetManager.updateAppWidget(timerWidget, remoteViews);
    }
}

提供者 XML

<?xml version="1.0" encoding="utf-8"?>
<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:initialLayout="@layout/activity_main"
    android:minHeight="144dp"
    android:minWidth="146dp"
    android:updatePeriodMillis="1000" />

list

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.poc_timerwidget"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="19" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <receiver
            android:name=".MainActivity"
            android:label="Timer Widget" >
            <intent-filter>
                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />
            </intent-filter>

            <meta-data
                android:name="android.appwidget.provider"
                android:resource="@xml/timer_widget_provider" />
        </receiver>
    </application>

</manifest>

最佳答案

问题:

1. AppWidgetProvider 是一个 BroadcastReceiver。您正在检索启动服务的 PendingIntent，而不是检索发送广播的 PendingIntent。
2. list 文件中的接收者有一个带有操作 ACTION_APPWIDGET_UPDATE 的 intent-filter。然而，操作 AppWidgetManager.ACTION_APPWIDGET_UPDATE 未在传递给警报管理器的未决 Intent 上设置。您还需要在待定 Intent 上设置额外的 AppWidgetManager.EXTRA_APPWIDGET_IDS。

设置重复闹钟以更新小部件:

Intent alarm = new Intent(context, MainActivity.class);
alarm.setAction(AppWidgetManager.ACTION_APPWIDGET_UPDATE); // Set appwidget update action
alarm.putExtra(AppWidgetManager.EXTRA_APPWIDGET_IDS, appWidgetIds); // Set appwidget ids to be updated
pendingIntent = PendingIntent.getBroadcast(context, 0, alarm,
    PendingIntent.FLAG_CANCEL_CURRENT); // get the broadcast pending intent
alarmManager.setRepeating(AlarmManager.RTC, System.currentTimeMillis(),
    1000, pendingIntent); // set repeat alarm 

记得将 updatePeriodMillis 设置为 0。来自 docs :

Set the alarm type to either ELAPSED_REALTIME or RTC, which will only deliver the alarm when the device is awake. Then set updatePeriodMillis to zero ("0").

关于android - onUpdate() 没有被小部件调用？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/25742300/