App Widget

1. 基本信息

App Widget是一种可以被放在其他应用中（如Launcher）并接收周期性更新的应用视图。这些视图在UI上就表现为Widget，并且你可以同App Widget Provider一起发布。

要创建一个App Widget，你需要完成以下步骤：

AppWidgetProviderInfo对象：它描述了App

Widget的基本元素，比如说布局、更新频率、AppWidgetProvider类等。这些都是在xml文件中定义的。
2.AppWidgetProvider类的实现：它定义了一些基本的方法以支持通过广播事件与App Widget交互。通过它，当App Widget被更新、启用、禁用以及删除时，你将收到相应的广播信息。
3.View Layout：通过xml文件定义App Widget的初始视图。

2. 添加App Widget布局

另外，你还可以实现一个App Widget的配置Activity。当然，这不是强制的。

要创建你的App Widget的初始布局，你可以使用以下View对象。

创建布局不是很麻烦，重点是，你必须记住，这个布局是基于RemoteViews的，不是所有的布局类型与View都支持。

一个RemoteViews对象可以支持以下布局类：

FrameLayout

LinearLayout

RelativeLayout

以及一下widget类

AnalogClock	Button	Chronometer	ImageButton
ImageView	ProgressBar	TextView	ViewFlipper

注：这些类的子类是不支持的。

res/layout文件夹下创建widget.xml文件

<code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-pi" style="color: rgb(0, 102, 102); box-sizing: border-box;"><?xml version="1.0" encoding="utf-8"?></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">LinearLayout</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span>
<span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:orientation</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"vertical"</span>
<span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:layout_width</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"match_parent"</span>
<span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:layout_height</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"match_parent"</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">TextView</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:layout_width</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"wrap_content"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:layout_height</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"wrap_content"</span>
<span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:text</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"当前时间"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:textColor</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"@android:color/white"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:textSize</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"18sp"</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:id</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"@+id/tv_weather"</span>/></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">LinearLayout</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li></ul>

3. 添加AppWidgetProviderInfo元数据

res/xml文件夹下创建weather.xml文件

<code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">appwidget-provider</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">xmlns:android</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"http://schemas.android.com/apk/res/android"</span>
<span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:minWidth</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"294dp"</span>
<span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:minHeight</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"72dp"</span>
<span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:updatePeriodMillis</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"86400000"</span>
<span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:previewImage</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"@drawable/preview"</span>
<span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:initialLayout</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"@layout/widget"</span>
<span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:configure</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"com.example.android.ExampleAppWidgetConfigure"</span>
<span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:resizeMode</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"horizontal|vertical"</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">appwidget-provider</span>></span>  </code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li></ul>

minWidth与minHeight属性表示了App Widget所需的最小布局区域。

默认的主屏中，App Widget要想确认其位置，需要通过基于网格的具有固定宽度和高度的单元。如果App Widget的最小宽度和高度无法匹配给定的单元，它将会自动扩展到最接近的单元大小。

由于主屏的布局方向是可变的，你应该考虑最坏的情况（每单元的宽和高都是74dp）。然而，为了防止在扩展时产生整数计算错误，你还需要减去2。因此，你可以用以下公式来计算最小宽度和高度（单位dp）：（单元数量×74）-2。

同时，为了保证你的App Widget能够在各种设备上正常使用，它们的宽度和高度必须不超过4×4个单元。

updatePeriodMillis属性定义了App

Widget框架调用AppWidgetProvider的onUpdate方法的频率。对于实际的更新，我们不建议采用该值进行实时处理。最好是越不频繁越好——为了保证电量，一小时不超过一次为好。当然，你也可以允许用户对更新频率进行设置。

注意，如果更新触发时设备正处于休眠状态，设备将唤醒以执行该操作。如果你的更新频率不超过一小时一次，这不会对电池的寿命产生多大的影响。但如果你需要更频繁地更新却又不想要在设备休眠时执行，那你可以使用定时器来执行更新。要达到这种目的，可以在AlarmManager中设置一个AppWidgetProvider能接收的Intent。将类型设为ELAPSED_REALTIME或RTC。由于AlarmManager只有当设备处于唤醒状态时才会被调用，我们只要设updatePeriodMillis为0即可。

linitialLayout属性标识了初始布局文件。
configure属性定义了当用户添加App Widget时调用的Activity。（这是可选的）
previewImage定义了App

Widget的缩略图，当用户从widget列表中选择时，显示的就是这张图。如果没设置，用户将看见的是你的应用的默认图标。
autoAdvanceViewId属性是在Android3.0引入的，用于标识需要被host（launcher）自动更新的widget的子视图。
resizeMode属性标识了widget重新布局的规则。你可以使用该属性来让widget能够在水平、竖直、或两个方向上均可变化。可用的值包括horizontal、vertical、none。如果是想在两个方向上均能拉伸，可设置为horizontal|vertical，当然，需要Android3.1以上版本。

4. 使用AppWidgetProvider类

<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ClockProvider</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">extends</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">AppWidgetProvider</span> {</span>
<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onEnabled</span>(Context context) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>.onEnabled(context);
Intent _intent = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Intent(context, ClockService.class);
context.startService(_intent);
}

<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onDisabled</span>(Context context) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>.onDisabled(context);
Intent _intent = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Intent(context, ClockService.class);
context.stopService(_intent);
}
<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onUpdate</span>(Context context, AppWidgetManager appWidgetManager, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span>[] appWidgetIds) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>.onUpdate(context, appWidgetManager, appWidgetIds);
}

}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li></ul>

onUpdate()

由updatePeriodMills定义的时间间隔触发。当然，添加Widget的时候也会，因此，应该在此处执行一些必要的配置，如定义View的事件处理handler，有必要的话，还会启动一个临时的Service。然而，如果你声明了一个配置Activity，该方法将不会在此时被调用。

onDelete(Context, int[])

当App Widget从host中移除时会被调用。

onEnabled(Context)

当App Widget的实例被第一次创建时，该方法将被调用。如果你建了两个实例，那该方法也只会被调用一次。

onDisabled(Context)

当最后一个App Widget的实例被删除时，该方法被调用。你可以在此处清除之前在onEnabled里执行的操作。

onReceive(Content, Intent)

每次接收到广播都会被调用，而且执行的顺序在上述方法之前。通常，你不需要实现该方法，因为AppWidgetProvider已经对各种不同类型的广播进行了过滤及分发。

注：在Android1.5中，有一个已知的问题，使得在某些情况下，onDeleted不会被调用。这时，你就需要实现onReceive()了。

5. 使用Service更新数据

<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ClockService</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">extends</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Service</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">implements</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">AMapLocalWeatherListener</span> {</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> LocationManagerProxy mLocationManagerProxy;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> SimpleDateFormat sdf;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> Timer timer;
<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> IBinder <span class="hljs-title" style="box-sizing: border-box;">onBind</span>(Intent intent) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>;
}

<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onCreate</span>() {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>.onCreate();
System.out.println(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"start"</span>);
sdf = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> SimpleDateFormat(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"yyyy-MM-dd HH:mm:ss"</span>);
timer = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Timer();
timer.schedule(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> TimerTask() {
<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">run</span>() {

String time = sdf.format(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Date());
updateViews(time);
}
},<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>,<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1000</span>);
}

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">updateViews</span>(String info)
{
Intent _intent = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Intent(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>, MainActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>, <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>, _intent, <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>);
RemoteViews views = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> RemoteViews(getPackageName(), R.layout.widget);
views.setTextViewText(R.id.tv_weather, info);
views.setOnClickPendingIntent(R.id.tv_weather, pendingIntent);<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//点击跳到主页</span>
AppWidgetManager manager = AppWidgetManager.getInstance(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>);
ComponentName name = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> ComponentName(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>, ClockProvider.class);
manager.updateAppWidget(name,views);
}

<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onDestroy</span>() {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>.onDestroy();
timer.cancel();
}
}
</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li><li style="box-sizing: border-box; padding: 0px 5px;">44</li><li style="box-sizing: border-box; padding: 0px 5px;">45</li></ul>

通过RemoteViews类和AppWidgetManager类发送广播更新界面数据

6.在AndroidManifest中声明一个App Widget

<code class="hljs xml has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">service</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:name</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">".ClockService"</span>></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">service</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">receiver</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:name</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">".ClockProvider"</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">intent-filter</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">action</span> <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:name</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"android.appwidget.action.APPWIDGET_UPDATE"</span>></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">action</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">intent-filter</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"><<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">meta-data
</span>                    <span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:name</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"android.appwidget.provider"</span>
<span class="hljs-attribute" style="box-sizing: border-box; color: rgb(102, 0, 102);">android:resource</span>=<span class="hljs-value" style="box-sizing: border-box; color: rgb(0, 136, 0);">"@xml/weather"</span>></span><span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">meta-data</span>></span>
<span class="hljs-tag" style="color: rgb(0, 102, 102); box-sizing: border-box;"></<span class="hljs-title" style="box-sizing: border-box; color: rgb(0, 0, 136);">receiver</span>></span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li></ul>

meta-data标签标识了AppWidgetProviderInfo资源，它需要以下属性：

android:name：使用android.appwidget.provider来标识AppWidgetProviderInfo。

android:resource：标识AppWidgetProviderInfo的资源位置。