Widgets高级篇(三)

kanwoerzi

浏览: 1646054 次

最近访客更多访客>>

u012363178

lynnlysh

zyysal

aaron198

博主相关

博客

微博

相册

留言

关于我

文章分类

全部博客 (1724)

社区版块

存档分类

2011-12 ( 292)
2011-11 ( 349)
2011-10 ( 284)
更多存档...

本文翻译整理自：<a rel="nofollow" href="http://developer.android.com/guide/topics/appwidgets/index.html#implementing_collections" style="color:rgb(207,121,28); line-height:22px; text-decoration:none">http://developer.android.com/guide/topics/appwidgets/index.html#implementing_collections</a> <div style="line-height:25px">3.6、设置数据项View的行为</div> <div style="line-height:25px">前文已经告诉你如何绑定您的数据到你的app widget collection。但是如何为数据项View添加动态的行为呢？本部分将讲述关于次的详细内容。</div> <div style="line-height:25px"> 在普通的App Widgets中，我们可以通过<a rel="nofollow" href="http://developer.android.com/reference/android/widget/RemoteViews.html#setOnClickPendingIntent(int,%20android.app.PendingIntent)" style="color:rgb(0,102,153); line-height:23px; text-decoration:none">setOnClickPendingIntent()</a>来设置View控件Click时，发送的Intent.通过次方法，我们就可以实现当用户点击一个按钮时，就启动一个Activity.但是这种方法对app widget collection的数据集的数据项View并不适用（你可以像Gmail app widget中一样通过setOnClickPendingIntent()来设置global button的click行为来启动一个应用程序, 但是对数据集的数据项View不能使用这种方法）。替代的是首先使用<a rel="nofollow" href="http://developer.android.com/reference/android/widget/RemoteViews.html#setOnClickFillInIntent(int,%20android.content.Intent)" style="color:rgb(0,102,153); line-height:23px; text-decoration:none">setOnClickFillInIntent()</a>方法为数据集的数据项View统一设置其Pending的Intent模板,然后在<a rel="nofollow" href="http://developer.android.com/reference/android/widget/RemoteViewsService.RemoteViewsFactory.html" style="color:rgb(0,102,153); line-height:23px; text-decoration:none">RemoteViewsFactory</a>中为数据集的数据项View的Pending的Intent模板的设置填充Intent。这样当数据项View在Click时，发送的Intent将是其Pending的Intent模板和其Pending的Intent模板填充Intent合成的Intent。 </div> <div style="line-height:25px"> </div> <div style="line-height:25px"> 在这里我们将使用<a target="_blank" href="http://hubingforever.blog.163.com/blog/static/17104057920116293109787/" style="color:rgb(207,121,28); line-height:22px; text-decoration:none">StackView Widget示例程序</a>来说明如何为数据项View添加Click行为。在<a target="_blank" href="http://hubingforever.blog.163.com/blog/static/17104057920116293109787/" style="color:rgb(207,121,28); line-height:22px; text-decoration:none">StackView Widget示例程序</a>中，当你单击一个数据项View,它将显示一个<code style="line-height:1em; color:rgb(0,112,0); font-family:monospace"><a rel="nofollow" href="http://developer.android.com/reference/android/widget/Toast.html" style="color:rgb(0,102,153); line-height:23px; text-decoration:none">Toast</a>消息</code>"Touched viewn,"n是它在touched view中的 index (position)。其主要执行流程如下： </div> <div style="line-height:25px"> 第一步：首先，在StackWidgetProvider(an AppWidgetProvider subclass)中使用<a rel="nofollow" href="http://developer.android.com/reference/android/widget/RemoteViews.html#setOnClickFillInIntent(int,%20android.content.Intent)" style="color:rgb(0,102,153); line-height:20px; text-decoration:none">setOnClickFillInIntent()</a>方法为数据集的数据项View统一设置其Pending的Intent模板，该intent有一个自定义的名叫TOAST_ACTION的action.在RemoteViewsFactory中为数据集的数据项View的Pending的Intent模板的设置填充Intent，填充Intent通过Extras把数据项View的index (position)携带在其中。 </div> <div style="line-height:25px"> 第二步、用户点击数据项View,其Pending的Intent模板和其Pending的Intent模板填充Intent被合成一个Intent，该Intent被激活并被发送。 </div> <div style="line-height:25px"> <div style="line-height:25px"> 第三步、数据项View发送的Intent广播被StackWidgetProvider接收，被传递到它的onReceive()中。 </div> <div style="line-height:25px"> 在onReceive()方法中，我们从Intent的Extra中提取其数据项view的index (position)，然后发送Toast消息。 </div> 注意：<a target="_blank" href="http://hubingforever.blog.163.com/blog/static/17104057920116293109787/" style="color:rgb(207,121,28); line-height:22px; text-decoration:none">StackView Widget示例程序</a>中使用的是把Intent发送到广播（StackWidgetProvider），但是一般的app widget只是简单的启动一 </div> <div style="line-height:25px">个Activity</div> <div style="line-height:25px">3.6.1、设置数据项View的pending intent模板</div> <div style="line-height:25px"></div> <div style="line-height:25px"></div> <div style="line-height:25px"> <div style="line-height:25px"> <div style="line-height:25px">在StackWidgetProvider (AppWidgetProvider subclass)，数据项View的pending intent模板被统一进行设置.</div> <div style="line-height:25px">不能对单个的数据项View的进行pending intent模板.你必须对数据集的数据项View的Pending的Intent模板进行统一设置，</div> <div style="line-height:25px">对于数据集的单个数据项View只能进行填充Intent设置，以便让每个数据项View都有个性化的Click行为。</div> </div> <div style="line-height:25px"> 在StackWidgetProvider中，它接受了用户click数据项View所发送的Intent，并在onReceive()对其进行了处理。 </div> <div style="line-height:25px">如果发现intent的action是TOAST_ACTION（即为用户click数据项View所发送的Intent）, app widget 将显示一个关于当前数据项View的Toast消息.</div> <div style="line-height:25px">示例7</div> <pre style="line-height:inherit; color:rgb(0,112,0); font-family:monospace; border-top-width:1px; border-right-width:1px; border-bottom-width:1px; border-left-width:1px; border-top-style:solid; border-right-style:solid; border-bottom-style:solid; border-left-style:solid; border-top-color:rgb(204,204,204); border-right-color:rgb(204,204,204); border-bottom-color:rgb(204,204,204); border-left-color:rgb(204,204,204); background-color:rgb(250,250,250); padding-top:10px; padding-right:10px; padding-bottom:10px; padding-left:10px; margin-top:0px; margin-bottom:1em; margin-left:1em; overflow-x:auto; overflow-y:auto">public class StackWidgetProvider extends AppWidgetProvider { public static final String TOAST_ACTION = "com.example.android.stackwidget.TOAST_ACTION"; public static final String EXTRA_ITEM = "com.example.android.stackwidget.EXTRA_ITEM"; ... // Called when the BroadcastReceiver receives an Intent broadcast. // Checks to see whether the intent's action is TOAST_ACTION. If it is, the app widget // displays a Toast message for the current item. @Override public void onReceive(Context context, Intent intent) { AppWidgetManager mgr = AppWidgetManager.getInstance(context); if (intent.getAction().equals(TOAST_ACTION)) { int appWidgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID); int viewIndex = intent.getIntExtra(EXTRA_ITEM, 0); Toast.makeText(context, "Touched view " + viewIndex, Toast.LENGTH_SHORT).show(); } super.onReceive(context, intent); } @Override public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) { // update each of the app widgets with the remote adapter for (int i = 0; i < appWidgetIds.length; ++i) { // Sets up the intent that points to the StackViewService that will // provide the views for this collection. Intent intent = new Intent(context, StackWidgetService.class); intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetIds[i]); // 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. intent.setData(Uri.parse(intent.toUri(Intent.URI_INTENT_SCHEME))); RemoteViews rv = new RemoteViews(context.getPackageName(), R.layout.widget_layout); rv.setRemoteAdapter(appWidgetIds[i], R.id.stack_view, intent); // The empty view is displayed when the collection has no items. It should be a sibling // of the collection view. rv.setEmptyView(R.id.stack_view, R.id.empty_view); // This section makes it possible for items to have individualized behavior. // It does this by setting up a pending intent template. Individuals items of a collection // cannot set up their own pending intents. Instead, the collection as a whole sets // up a pending intent template, and the individual items set a fillInIntent // to create unique behavior on an item-by-item basis. Intent toastIntent = new Intent(context, StackWidgetProvider.class); // Set the action for the intent. // When the user touches a particular view, it will have the effect of // broadcasting TOAST_ACTION. toastIntent.setAction(StackWidgetProvider.TOAST_ACTION); toastIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetIds[i]); intent.setData(Uri.parse(intent.toUri(Intent.URI_INTENT_SCHEME))); PendingIntent toastPendingIntent = PendingIntent.getBroadcast(context, 0, toastIntent, PendingIntent.FLAG_UPDATE_CURRENT); rv.setPendingIntentTemplate(R.id.stack_view, toastPendingIntent); appWidgetManager.updateAppWidget(appWidgetIds[i], rv); } super.onUpdate(context, appWidgetManager, appWidgetIds); } }</pre> <div style="line-height:25px">3.6.2、设置数据项View的填充intent</div> <div style="line-height:25px">你必须在RemoteViewsFactory中对数据集的每个数据项View设置填充intent，以用于区分是哪个数据项View.</div> 当用户点击数据项View,其Pending的Intent模板和其填充Intent被合成一个最终的Intent，并进行广播发送。 </div> <div style="line-height:25px">示例8</div> <div style="line-height:25px"> <pre style="line-height:inherit; color:rgb(0,112,0); font-family:monospace; border-top-width:1px; border-right-width:1px; border-bottom-width:1px; border-left-width:1px; border-top-style:solid; border-right-style:solid; border-bottom-style:solid; border-left-style:solid; border-top-color:rgb(204,204,204); border-right-color:rgb(204,204,204); border-bottom-color:rgb(204,204,204); border-left-color:rgb(204,204,204); background-color:rgb(250,250,250); padding-top:10px; padding-right:10px; padding-bottom:10px; padding-left:10px; margin-top:0px; margin-bottom:1em; margin-left:1em; overflow-x:auto; overflow-y:auto">public class StackWidgetService extends RemoteViewsService { @Override public RemoteViewsFactory onGetViewFactory(Intent intent) { return new StackRemoteViewsFactory(this.getApplicationContext(), intent); } } class StackRemoteViewsFactory implements RemoteViewsService.RemoteViewsFactory { private static final int mCount = 10; private List<WidgetItem> mWidgetItems = new ArrayList<WidgetItem>(); private Context mContext; private int mAppWidgetId; public StackRemoteViewsFactory(Context context, Intent intent) { mContext = context; mAppWidgetId = intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID); } // Initialize the data set. public void onCreate() { // In onCreate() you set up any connections / cursors to your data source. Heavy lifting, // for example downloading or creating content etc, should be deferred to onDataSetChanged() // or getViewAt(). Taking more than 20 seconds in this call will result in an ANR. for (int i = 0; i < mCount; i++) { mWidgetItems.add(new WidgetItem(i + "!")); } ... } ... // Given the position (index) of a WidgetItem in the array, use the item's text value in // combination with the app widget item XML file to construct a RemoteViews object. public RemoteViews getViewAt(int position) { // position will always range from 0 to getCount() - 1. // Construct a RemoteViews item based on the app widget item XML file, and set the // text based on the position. RemoteViews rv = new RemoteViews(mContext.getPackageName(), R.layout.widget_item); rv.setTextViewText(R.id.widget_item, mWidgetItems.get(position).text); // Next, set a fill-intent, which will be used to fill in the pending intent template // that is set on the collection view in StackWidgetProvider. Bundle extras = new Bundle(); extras.putInt(StackWidgetProvider.EXTRA_ITEM, position); Intent fillInIntent = new Intent(); fillInIntent.putExtras(extras); // Make it possible to distinguish the individual on-click // action of a given item rv.setOnClickFillInIntent(R.id.widget_item, fillInIntent); ... // Return the RemoteViews object. return rv; } ... }</pre> </div>

分享到：