Question

目前，我的AppWidgetProvider拥有静态数据。它用于传递AppWidgetProvider＆amp;的信息。 RemoteViewsService.RemoteViewsFactory

public class MyAppWidgetProvider extends AppWidgetProvider {
    // Key will be widget id
    private static Map<Integer, Holder> holderMap = new java.util.concurrent.ConcurrentHashMap<Integer, Holder>();

    public static int getClickedColumn(int appWidgetId) {
        Holder holder = holderMap.get(appWidgetId);  
        if (holder == null) {
            return -1;
        }
        return holder.clickedColumn;
    }

public class AppWidgetRemoteViewsFactory implements RemoteViewsService.RemoteViewsFactory {
    @Override
    public void onDataSetChanged() {
        int clickedColumn = MyAppWidgetProvider.getClickedColumn(mAppWidgetId);

调用AppWidgetProvider的静态方法在大多数情况下都能正常工作。

但是，有时候，如果我将小部件放到主屏幕上，让它在那里待几个小时。当我回来并且ListView时，我可能会随机收到以下错误。

java.lang.ExceptionInInitializerError
    at org.yccheok.project.gui.widget.AppWidgetRemoteViewsFactory.onDataSetChanged(AppWidgetRemoteViewsService.java:390)
    at android.widget.RemoteViewsService$RemoteViewsFactoryAdapter.onDataSetChanged(RemoteViewsService.java:142)
    at com.android.internal.widget.IRemoteViewsFactory$Stub.onTransact(IRemoteViewsFactory.java:49)
    at android.os.Binder.execTransact(Binder.java:367)
    at dalvik.system.NativeStart.run(Native Method)
Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
    at android.os.Handler.<init>(Handler.java:121)
    at org.yccheok.project.gui.widget.MyAppWidgetProvider.<clinit>(MyAppWidgetProvider.java:564)

从<clinit>，我怀疑MyAppWidgetProvider被操作系统破坏了吗？这个原因AppWidgetRemoteViewsFactory想要在调用静态函数之前执行类初始化吗？

这是否意味着，操作系统可以随时销毁MyAppWidgetProvider，我们不应该在其中放置可共享的静态数据？

如果是这样，在AppWidgetProvider和RemoteViewsService.RemoteViewsFactory之间共享数据的正确方法是什么？（除了使用File或SharedPreferences）

Answer 1

RemoteViewsFactory - ＆gt;的AppWidgetProvider

从RemoteViewsFactory到AppWidgetProvider的通信可以使用Broadcasts完成，例如像这样：

Intent intent = new Intent(ACTION_PROGRESS_OFF); intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, mAppWidgetId); LocalBroadcastManager.getInstance(mContext).sendBroadcast(intent);

AppWidgetProvider接收如下事件：

@Override public void onReceive(final Context context, final Intent intent) { // here goes the check if the app widget id is ours final String action = intent.getAction(); if (ACTION_PROGRESS_OFF.equals(action)) { // turn off the refresh spinner

当然，需要在清单中定义广播操作：

<receiver android:name="..."> <intent-filter> <action android:name="android.appwidget.action.APPWIDGET_UPDATE" /> <action android:name="myPackage.ACTION_PROGRESS_OFF" /> </intent-filter> <meta-data ... /> </receiver>

AppWidgetProvider - ＆gt; RemoteViewsFactory

与RemoteViewsFactory通信的一种方式（在您的情况下可能是最好的方法）是将信息发送到您传递给RemoteViewsAdapter的服务的意图中：

Intent intentRVService = new Intent(context, RemoteViewsService.class); intentRVService.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetId); // let's put in some extra information we want to pass to the RemoteViewsFactory intentRVService.putExtra("HELLO", "WORLD"); // when intents are compared, the extras are ignored, so we need to // embed the extras into the data so that the extras will not be ignored intentRVService.setData(Uri.parse(intentRVService.toUri(Intent.URI_INTENT_SCHEME))); rv.setRemoteAdapter(appWidgetId, R.id.my_list, intentRVService); rv.setEmptyView(R.id.my_list, android.R.id.empty); // create the pending intent template for individual list items ... rv.setPendingIntentTemplate(R.id.my_list, pendingIntentTemplate); appWidgetMgr.notifyAppWidgetViewDataChanged(appWidgetId, R.id.my_list);

RemoteViewsService可以轻松地从意图中检索信息并将其传递给RemoteViewsService.RemoteViewsFactory。

我不能100％确定您的小部件何时以及如何决定对数据进行排序，但我假设如果用户选择要排序的列，那么您必须使用notifyAppWidgetViewDataChanged进行更新周期，然后你会传递那一列。如果您稍后需要该信息，那么您必须以某种方式存储信息（SharedPreferences）。

在AppWidgetProvider和RemoteViewsService.RemoteViewsFactory之间共享数据的正确方法是什么

1 个答案: