从小部件启动/停止服务 [英] Start/Stop Service from Widget

问题描述

我想从小部件内部启动服务，我知道我可以像使用PendingIntent一样

I want to start a service from inside the widget, I know that i can do it using PendingIntent like

PendingIntent intent = PendingIntent.getService(context, 0, new Intent(context, MyService.class), Intent.FLAG_ACTIVITY_NEW_TASK);
remoteViews.setOnClickPendingIntent(R.id.buttonWidgetStartService, intent);

，但是问题是我已经在该按钮上使用了PendingIntent用于其他用途. 因此，我尝试使用

but the problem is that I've already used PendingIntent on that button for some other purpose. So, I tried starting the service using

context.startService(new Intent(context, MyService.class));

在这里我得到NullPointerException.

这是我的代码:

public class WiNetWidget extends AppWidgetProvider {

    public static String TOGGLE_WINET = "ToggleWiNetService";
    private static boolean serviceRunning = false;
    private static Intent serviceIntent;
    @Override
    public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {
        final int N = appWidgetIds.length;
        serviceIntent = new Intent(context, WiNetService.class);

        for (int i=0; i<N; i++) {
            int appWidgetId = appWidgetIds[i];
            RemoteViews remoteViews = new RemoteViews(context.getPackageName(), R.layout.widget_winet);

            remoteViews.setViewVisibility(R.id.buttonWidgetLoading, View.INVISIBLE);
            remoteViews.setViewVisibility(R.id.buttonWidgetStartService, View.VISIBLE);

            Intent newIntent = new Intent(context, WiNetWidget.class);
            newIntent.setAction(TOGGLE_WINET);
            PendingIntent pendingIntent = PendingIntent.getBroadcast(context, 0, newIntent, 0);
            remoteViews.setOnClickPendingIntent(R.id.buttonWidgetStartService, pendingIntent);
            remoteViews.setOnClickPendingIntent(R.id.buttonWidgetStopService, pendingIntent);

            appWidgetManager.updateAppWidget(appWidgetId, remoteViews);
            Log.i(TOGGLE_WINET, "updated");
        }
    }

    @Override
    public void onReceive(Context context, Intent intent) {
        if(intent.getAction().equals(TOGGLE_WINET)) {
            RemoteViews remoteViews = new RemoteViews(context.getPackageName(), R.layout.widget_winet);
            if(serviceRunning) {
                context.stopService(serviceIntent);
                remoteViews.setViewVisibility(R.id.buttonWidgetStartService, View.VISIBLE);
                remoteViews.setViewVisibility(R.id.buttonWidgetStopService, View.INVISIBLE);
                Toast.makeText(context, "serviceStopped", Toast.LENGTH_SHORT).show();
            } else {
                context.startService(serviceIntent);
                remoteViews.setViewVisibility(R.id.buttonWidgetStopService, View.VISIBLE);
                remoteViews.setViewVisibility(R.id.buttonWidgetStartService, View.INVISIBLE);
                Toast.makeText(context, "serviceStarted", Toast.LENGTH_SHORT).show();
            }
            serviceRunning=!serviceRunning;
            ComponentName componentName = new ComponentName(context, WiNetWidget.class);
            AppWidgetManager.getInstance(context).updateAppWidget(componentName, remoteViews);
        }
        super.onReceive(context, intent);
    }
}

注意:如果删除包含startService和stopService的行，则一切运行顺利.

Note: If I remove the lines containing startService and stopService, everything is running smoothly.

先谢谢了！！ :)

推荐答案

问题是您一次创建一个一次性的Intent，但多次使用它.每次您要启动或停止Service时，最好创建一个新的Intent，如下所示:

The issue is that you create a one-shot Intent once, but use it multiple times. Better to create a fresh Intent every time you want to start or stop the Service as follows:

@Override
public void onReceive(Context context, Intent intent) {
    if(intent.getAction().equals(TOGGLE_WINET)) {
        RemoteViews remoteViews = new RemoteViews(context.getPackageName(), R.layout.widget_winet);

        // Create a fresh intent 
        Intent serviceIntent = new Intent(context, WiNetService.class);

        if(serviceRunning) {
            context.stopService(serviceIntent);
            remoteViews.setViewVisibility(R.id.buttonWidgetStartService, View.VISIBLE);
            remoteViews.setViewVisibility(R.id.buttonWidgetStopService, View.INVISIBLE);
            Toast.makeText(context, "serviceStopped", Toast.LENGTH_SHORT).show();
        } else {
            context.startService(serviceIntent);
            remoteViews.setViewVisibility(R.id.buttonWidgetStopService, View.VISIBLE);
            remoteViews.setViewVisibility(R.id.buttonWidgetStartService, View.INVISIBLE);
            Toast.makeText(context, "serviceStarted", Toast.LENGTH_SHORT).show();
        }
        serviceRunning=!serviceRunning;
        ComponentName componentName = new ComponentName(context, WiNetWidget.class);
        AppWidgetManager.getInstance(context).updateAppWidget(componentName, remoteViews);
    }
    super.onReceive(context, intent);
}

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