Android AppWidget实例验证
1.创建AppWidget布局，包含两个TextView用来显示内容：?
- <?xml?version="1.0"?encoding="utf-8"?>??
- <LinearLayout?xmlns:android="http://schemas.android.com/apk/res/android"??
- ????android:layout_width="fill_parent"?android:layout_height="fill_parent"??
- ????android:orientation="vertical">??
- ????<TextView?android:layout_height="wrap_content"??
- ????????android:layout_width="fill_parent"?android:id="@+id/tv1"??
- ????????android:textColor="#FF0000"?android:textSize="24sp"?android:textStyle="bold"??
- ????????android:text="-1"></TextView>??
- ????<TextView?android:layout_height="wrap_content"?android:id="@+id/tv2"??
- ????????android:textSize="24sp"?android:textStyle="bold"?android:textColor="#00FF00"??
- ????????android:layout_width="fill_parent"?android:text="-2"></TextView>??
- </LinearLayout>??
2.在res下创建xml目录，再在xml目录里面创建AppWidget信息xml文件：?
2.1新建xml文件时，type选择AppWidget Provider。?
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2.2填充属性：?
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宽高的计算公式为：占用屏幕格数*74-2?
Update period millis：设置为0，手动刷新。根据实验，设置不为0时，至少在2.2上系统根本不按照设置的值刷新，还是自己控制刷新时机好了。?
Initial layout：就添控件要使用的布局。?
Configure暂时不用，留空。?
3.创建AppWidgetDemo类：?
?
重载AppWidgetProvider中的所有函数，每个函数里面增加输出语句，以查看调用顺序。?
- public?class?AppWidgetDemo?extends?AppWidgetProvider?{??
- ??
- ????@Override??
- ????public?void?onDeleted(Context?context,?int[]?appWidgetIds)?{??
- ??????????
- ????????super.onDeleted(context,?appWidgetIds);??
- ????????Log.e("AppWidgetDemo",?"onDeleted");??
- ????}??
- ??
- ????@Override??
- ????public?void?onDisabled(Context?context)?{??
- ??????????
- ????????super.onDisabled(context);??
- ????????Log.e("AppWidgetDemo",?"onDisabled");??
- ????}??
- ??
- ????@Override??
- ????public?void?onEnabled(Context?context)?{??
- ??????????
- ????????super.onEnabled(context);??
- ????????Log.e("AppWidgetDemo",?"onEnabled");??
- ????}??
- ??
- ????@Override??
- ????public?void?onReceive(Context?context,?Intent?intent)?{??
- ??????????
- ????????super.onReceive(context,?intent);??
- ????????Log.e("AppWidgetDemo",?"onReceive,Action:"?+?intent.getAction());??
- ????}??
- ??
- ????@Override??
- ????public?void?onUpdate(Context?context,?AppWidgetManager?appWidgetManager,?int[]?appWidgetIds)?{??
- ??????????
- ????????super.onUpdate(context,?appWidgetManager,?appWidgetIds);??
- ????????Log.e("AppWidgetDemo",?"onUpdate,Count:"?+?appWidgetIds.length);??
- ????}??
- ??
- }??
4.在AndroidManifest.xml文件中声明此Widget：?
添加一个Receiver，其name为AppWidgetDemo类的类名。?
- <receiver?android:name="AppWidgetDemo"></receiver>??
为此Receiver添加Intent filter，接收系统发出android.appwidget.action.APPWIDGET_UPDATE的Intent。?
- <receiver?android:name="AppWidgetDemo">??
- ????<intent-filter>??
- ????????<action?android:name="android.appwidget.action.APPWIDGET_UPDATE"></action>??
- ????</intent-filter>????????????
- </receiver>??
此外还要为此receiver添加meta-data信息，以告知系统相关的AppWidgetProvider信息：?
- <meta-data?android:name="android.appwidget.provider"??
- ????????????????android:resource="@xml/widget_info_demo"></meta-data>??
meta-data的name是约定好的android.appwidget.provider，resource则是第2步创建的AppWidget信息xml文件。?
5.至此AppWidget已经可用了，安装到模拟器上看下运行流程。?
5.1添加一个Widget到桌面上：?
onEnabled被呼叫：按照说明，当桌面上出现第一个此Widget的实例时，此函数被呼叫。?
onReceive被呼叫：onReceive,Action:android.appwidget.action.APPWIDGET_ENABLED?
onUpdate被呼叫：onUpdate,Count:1，并且待更新的AppWidget数量为1?
onReceive被呼叫：onReceive,Action:android.appwidget.action.APPWIDGET_UPDATE?
5.2再添加一个Widget到桌面上：?
onUpdate被呼叫:onUpdate,Count:1，并且待更新的AppWidget数量仍然为1，而不是2。?
onReceive被呼叫：onReceive,Action:android.appwidget.action.APPWIDGET_UPDATE?
5.3从桌面上移除一个Widget：?
onDeleted：每个实例被移除时都会被呼叫?
onReceive,Action:android.appwidget.action.APPWIDGET_DELETED?
5.4再从桌面上移除一个Widget：?
onDeleted：仍然执行?
onReceive,Action:android.appwidget.action.APPWIDGET_DELETED?
onDisabled：因为是最后一个活动的实例被移除了，所以被呼叫。?
onReceive,Action:android.appwidget.action.APPWIDGET_DISABLED?
6.刷新AppWidget?
6.1在onUpdate()中刷新：?
onUpdate在AppWidget放到桌面时会被调用，在Update period millis达到时可能会被调用。?
- RemoteViews?appWidgetView?=?new?RemoteViews(context.getPackageName(),?R.layout.widget_layout_demo);??
- appWidgetView.setTextViewText(R.id.tv1,?String.valueOf(mCount));??
- appWidgetView.setTextViewText(R.id.tv2,?String.valueOf(mCount));??
- appWidgetManager.updateAppWidget(appWidgetIds,?appWidgetView);??
先获取一个RemoteViews，也就是AppWidget的布局所对应的View；?
使用指定的Id更新要更新的控件；?
更新整个RemoteViews，此时就可以更新AppWidget内容了。?
但是这样的代码还有一个问题，当向桌面依次添加多个控件时会出现下面这样的效果：?
?
即更新时没有同时更新所有的AppWidget，这是因为onUpdate中传进来的数组中只包含了1个id，如果想同时更新多个，那么可以把更新语句更换为：?
- appWidgetManager.updateAppWidget(new?ComponentName(context,?AppWidgetDemo.class),?appWidgetView);??
通过组件名可以把所有的名字符合的AppWidget都更新。?
6.2在onReceive()中更新?
6.2.1自定义Action通知刷新：?
在AndroidManifest.xml中定义的receiver的intent-filter增加一个自定义的Action：?
com.demo.appwidget.refresh?
- ?<receiver?android:name="AppWidgetDemo">??
- <intent-filter>??
- ????<action?android:name="android.appwidget.action.APPWIDGET_UPDATE"></action>??
- ????<action?android:name="com.demo.appwidget.refresh"></action>??
- </intent-filter>??
- <meta-data?android:name="android.appwidget.provider"??
- ????android:resource="@xml/widget_info_demo"></meta-data>??
- lt;/receiver>??
包含此Action的Intent可以在后台服务或者Activity中发出，然后会被此Receiver接收，进而触发onReceive。?
本例中采用按钮按下时广播intent：?
- btnSend.setOnClickListener(new?OnClickListener()?{????????????
- ????????????public?void?onClick(View?v)?{??
- ????????????????Intent?intent?=?new?Intent();??
- ????????????????intent.setAction("com.demo.appwidget.refresh");??
- ????????????????intent.putExtra("value",?teInput.getText().toString());??
- ????????????????SendMsgActivity.this.sendBroadcast(intent);??
- ????????????}??
- ????????});??
在接收端：?
- if(intent.getAction().equals("com.demo.appwidget.refresh"))?{??
- ????????????String?value?=?intent.getStringExtra("value");????????????
- ????????????RemoteViews?appWidgetView?=?new?RemoteViews(context.getPackageName(),?R.layout.widget_layout_demo);??
- ????????????appWidgetView.setTextViewText(R.id.tv1,?value);??
- ????????????appWidgetView.setTextViewText(R.id.tv2,?value);??
- ????????????AppWidgetManager.getInstance(context).updateAppWidget(new?ComponentName(context,?AppWidgetDemo.class),?appWidgetView);??
- ????????}??
判断是否是感兴趣的Action，是的话就取值，然后更新。?
6.2.2接收系统消息刷新：?
比如intent-filter中再增加一个action："android.provider.Telephony.SMS_RECEIVED"，在AndroidMenifest.xml中任意位置添加<uses-permission android:name="android.permission.RECEIVE_SMS" />设置好权限，当系统有短消息收到时就能触发onReceive了。?
但是有些Action比较特殊，比如android.intent.action.TIME_TICK，根据android.content.intent文档中的描述：You can not receive this through components declared in manifests, only by exlicitly registering for it with Context.registerReceiver().?
这个Action在AndroidManifest.xml中声明了也没用，必须要自己开个服务注册receiver才能收到，然后再转发一次给自己。?
6.3直接在外部Activity或者Service中刷新：?
- btnRefresh.setOnClickListener(new?OnClickListener()?{?????????????
- ????public?void?onClick(View?v)?{??
- ????????String?value?=?teInput.getText().toString();??
- ????????RemoteViews?appWidgetView?=?new?RemoteViews(SendMsgActivity.this.getPackageName(),?R.layout.widget_layout_demo);??
- ????????appWidgetView.setTextViewText(R.id.tv1,?value);??
- ????????appWidgetView.setTextViewText(R.id.tv2,?value);??
- ????????AppWidgetManager.getInstance(SendMsgActivity.this)??
- ????????????.updateAppWidget(new?ComponentName(SendMsgActivity.this,?AppWidgetDemo.class),?appWidgetView);??
- ????}??
- });??
此段代码可直接刷新AppWidget的内容，不会触发其onUpdate()。?
7.响应点击事件?
因为onUpdate是每个AppWidget被放置到桌面上时都会被呼叫的函数，所以在此函数中完成事件的关联：?
- Intent?intent?=?new?Intent(context,?SendMsgActivity.class);??
- PendingIntent?pendingIntent?=?PendingIntent.getActivity(context,?0,?intent,?0);??
- appWidgetView.setOnClickPendingIntent(R.id.tv1,?pendingIntent);??
另外要注意此段代码必须要在appWidgetManager.updateAppWidget()之前，否则是不会生效的。?
运行后可以点击AppWidget的第一个控件，就能呼叫指定的Activity了。?
8.Config Activity?
这个可直接参考SDK文档中的Dev Guide-->App Widgets了。
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