Android:如何强制更新特定类型的所有小部件 [英] Android: How do I force the update of all widgets of a particular kind

问题描述

我已经看到很多类似的问题，而且我一遍又一遍地看到相同的答案.我不想为我的应用拥有的每一种小部件都提供一个服务，尤其是看到我的应用已经有 2 个持久服务.

I have seen many questions along these lines, and I keep seeing the same answer over and over. I don't want to have to have a Service for every kind of widget my app has, especially seeing as my app already has 2 persistent services.

具体来说，如果我的现有服务之一发现数据已更改，我想更新我的小部件.在计时器上执行此操作很烦人，因为更新之间可能需要几天时间，或者一小时内可能会有好几次.我希望我的小部件始终显示最新信息.

Specifically, if one of my existing services sees that data has changed, I want to update my widgets. Doing this on a timer is annoying, as it could be days between updates or there might be several within one hour. I want my widgets to ALWAYS show up to date information.

Android 小部件设计似乎是在您的小部件在需要时提取信息的基础上工作的，我认为有许多明智的场景是活动可能希望将数据推送到小部件.

Android widget design seems to work on the basis that your widget pulls information when it wants it, I think there are many sensible scenarios where an activity may wish to push data to a widget.

阅读下面的答案，了解我如何准确地做到这一点.据我所知，如果处理得当，不会有任何不良影响.

Read the answer below for how I worked out how to do precisely this. As far as I can see there are no adverse effects if it is done properly.

推荐答案

要强制更新特定小部件提供程序的小部件，我们需要执行以下操作:

To force our widgets for a particular widget provider to be updated, we will need to do the following:

• 设置我们的提供商以接收专门的广播
• 发送专业广播:

• Set up our provider to receive a specialized broadcast
• Send the specialized broadcast with:

1. 与提供者关联的所有当前小部件 ID
2. 要发送的数据
3. 只有我们的提供商才会响应的键(重要！)

让我们的小部件在点击时更新(没有服务！)

第 1 步 - 设置我们的 AppWidgetProvider

我不会详细介绍如何创建 info xml 文件或更改 Android Manifest - 如果您不知道如何正确创建小部件，那么您应该先阅读大量教程.

I will not go through the details of creating the info xml file or changes to the Android Manifest - if you don't know how to create a widget properly, then there are plenty of tutorials out there you should read first.

这是一个示例 AppWidgetProvider 类:

public class MyWidgetProvider extends AppWidgetProvider {

public static final String WIDGET_IDS_KEY ="mywidgetproviderwidgetids";
public static final String WIDGET_DATA_KEY ="mywidgetproviderwidgetdata";

}

@Override
public void onReceive(Context context, Intent intent) {
    if (intent.hasExtra(WIDGET_IDS_KEY)) {
        int[] ids = intent.getExtras().getIntArray(WIDGET_IDS_KEY);
        if (intent.hasExtra(WIDGET_DATA_KEY)) {
           Object data = intent.getExtras().getParcelable(WIDGET_DATA_KEY);
           this.update(context, AppWidgetManager.getInstance(context), ids, data);
        } else {
            this.onUpdate(context, AppWidgetManager.getInstance(context), ids);
        }
    } else super.onReceive(context, intent);
}

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

//This is where we do the actual updating
public void update(Context context, AppWidgetmanager manager, int[] ids, Object data) {

    //data will contain some predetermined data, but it may be null
   for (int widgetId : ids) {
        .
        .
        //Update Widget here
        .
        .
        manager.updateAppWidget(widgetId, remoteViews);
    }
}

第 2 步 - 发送广播

在这里我们可以创建一个静态方法来更新我们的小部件.在小部件更新操作中使用我们自己的键很重要，如果我们使用 AppWidgetmanager.EXTRA_WIDGET_IDS，我们不仅会破坏我们自己的小部件，还会破坏其他小部件.

Here we can create a static method that will get our widgets to update. It is important that we use our own keys with the widget update action, if we use AppWidgetmanager.EXTRA_WIDGET_IDS we will not only break our own widget, but others as well.

public static void updateMyWidgets(Context context, Parcelable data) {
    AppWidgetManager man = AppWidgetManager.getInstance(context);
    int[] ids = man.getAppWidgetIds(
            new ComponentName(context,MyWidgetProvider.class));
    Intent updateIntent = new Intent();
    updateIntent.setAction(AppWidgetManager.ACTION_APPWIDGET_UPDATE);
    updateIntent.putExtra(MyWidgetProvider.WIDGET_ID_KEY, ids);
    updateIntent.putExtra(MyWidgetProvider.WIDGET_DATA_KEY, data);
    context.sendBroadcast(updateIntent);
}

如果将此方法与多个提供商一起使用，请确保他们使用不同的密钥.否则，您可能会发现小部件 a 的代码正在更新小部件 b，这可能会产生一些奇怪的后果.

If using this method with multiple providers MAKE SURE they use different keys. Otherwise you may find widget a's code updating widget b and that can have some bizarre consequences.

第 3 步 - 点击更新

另一件好事是让我们的小部件在被点击时神奇地更新.将以下代码添加到更新方法中以实现此目的:

Another nice thing to do is to get our widget to update magiacally whenever it is clicked. Add the following code into the update method to acheive this:

RemoteViews views = 
      new RemoteViews(context.getPackageName(),R.layout.mywidget_layout);

Intent updateIntent = new Intent();
updateIntent.setAction(AppWidgetManager.ACTION_APPWIDGET_UPDATE);
updateIntent.putExtra(myWidgetProvider.WIDGET_IDS_KEY, ids);
PendingIntent pendingIntent = PendingIntent.getBroadcast(
      context, 0, updateIntent, PendingIntent.FLAG_UPDATE_CURRENT);

views.setOnClickPendingIntent(R.id.view_container, pendingIntent);

此代码将导致在单击小部件时调用 onUpdate 方法.

This code will cause the onUpdate method to be called whenever the widget is clicked on.

备注

• 对 updateWidgets() 的任何调用都会导致我们的小部件的所有实例都被更新.
• 单击小部件将导致我们的小部件的所有实例被更新
• 无需服务
• 当然，请注意不要经常更新 - 小部件更新会消耗电池电量.
• 请记住，所有小部件提供者都会收到广播，我们的特殊密钥可确保只有我们的小部件实际更新.

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