Android(安卓)widget定时更新及事件处理

最近在项目里用到widget ，涉及到widget 的定时更新和事件监控与处理。具体效果如图：

功能：

实现定时更新

能展示同一组数据，update 时更新数据源

可以监听事件，并作出不同反应

实现分析：

SDK1.5 之后android:updatePeriodMillis 就失效，改为默认更新，为了实现自定义定时更新，用到了定时器主动更新；

widget 由其它应用程序托管，共用数据十分困难，我将数据写入sharedpreferences ，以记录数据源;

widget 各种状态都是由消息控制，为方便事件管理，向系统注册接受器。

首先在AndroidManifest.xml 文件中注册widget:

<receiver
android:name=".widget"
android:label="@string/app_name"
>
<intent-filter>
<actionandroid:name="android.appwidget.action.APPWIDGET_UPDATE"/>
</intent-filter>
<meta-data
android:name="android.appwidget.provider"
android:resource="@xml/widget"
/>
</receiver>


添加res/xml/widget.xml设置widget属性：

<appwidget-provider
xmlns:android="http://schemas.android.com/apk/res/android"
android:minWidth="294dip"
android:minHeight="72dip"
android:updatePeriodMillis="5000" 
    android:initialLayout="@layout/appwidget"
>
</appwidget-provider>

实现定时更新，只需在widget第一次创建或系统重启时开启计时器，于是给来自计时器的消息加上sheme以区分：

publicstaticfinalStringURI_SCHEME="widget";

publicvoidonReceive(Contextcontext,Intentintent){

if(AppWidgetManager.ACTION_APPWIDGET_UPDATE.equals(intent.getAction()))

finalint[]appWidgetIds=intent.getExtras().getIntArray(AppWidgetManager.EXTRA_APPWIDGET_IDS);

for(intappWidgetId:appWidgetIds)

{

if(appWidgetId==AppWidgetManager.INVALID_APPWIDGET_ID)

continue;

//scheme不等于URI_SCHEME说明这个消息来自系统

//定时更新或是widget第一次创建或是系统重启

if(!URI_SCHEME.equals(intent.getScheme())){

setAlarm(context,appWidgetId,updateTime);

}

else{

//可以在这里修改更新时间,如果有必要

//例如：

//setAlarm(context,appWidgetId,theValueComeFromPreference

}

super.onReceive(context,intent);

}

privatevoidsetAlarm(Contextcontext,intappWidgetId,intupdateRateSeconds){
IntentwidgetUpdate=newIntent();
widgetUpdate.setAction(AppWidgetManager.ACTION_APPWIDGET_UPDATE);
widgetUpdate.putExtra(AppWidgetManager.EXTRA_APPWIDGET_IDS,newint[]{appWidgetId});
//给来自计时器的消息加标识
widgetUpdate.setData(Uri.withAppendedPath(Uri.parse(URI_SCHEME+"://widget/id/"),String.valueOf(appWidgetId)));
PendingIntentnewPending=PendingIntent.getBroadcast(context,0,widgetUpdate,PendingIntent.FLAG_UPDATE_CURRENT);
AlarmManageralarms=(AlarmManager)context.getSystemService(Context.ALARM_SERVICE);
if(updateRateSeconds>=0){
alarms.setRepeating(AlarmManager.ELAPSED_REALTIME,SystemClock.elapsedRealtime(),updateRateSeconds,newPending);
}else{
alarms.cancel(newPending);
}
}

要接受来自计时器的消息，需要在AndroidManifest.xml另注册接受器：

<receiver
android:name=".widget"
android:label="@string/app_name"
>
<intent-filter>
<actionandroid:name="com.example.widget.APPWIDGET_UPDATE"/>
<dataandroid:scheme="widget"/>
</intent-filter>
<meta-dataandroid:name="android.appwidget.provider"
android:resource="@xml/widget"
/>
</receiver>

实现了定时更新。接下来展示界面：

publicstaticfinalStringPREFS_NAME="com.example.widget_preferences";
publicstaticfinalStringPREFS_WIDGET_DATA="WidgetData-%d";
publicstaticfinalStringPREFS_CURRENT_INDEX="CurrentIndex-%d";
privatestaticfinalStringACTION_WIDGET_CONTROL="com.example.widget.WIDGET_CONTROL";
publicvoidonUpdate(Contextcontext,AppWidgetManagerappWidgetManager,
int[]appWidgetIds){
//TODOAuto-generatedmethodstub
finalintN=appWidgetIds.length;
SharedPreferencesshared=context.getSharedPreferences(PREFS_NAME,0);
SharedPreferences.Editoreditor=shared.edit();
for(inti=0;i<N;i++)
{
if(appWidgetIds[i]==AppWidgetManager.INVALID_APPWIDGET_ID)
continue;
intappWidgetId=appWidgetIds[i];
StringwidgetDataStr=“data1=value|||data2=value|||data3=value|||data4=value”;
editor.putString(String.format(PREFS_WIDGET_DATA,appWidgetIds[i]),widgetDataStr);
editor.putInt(String.format(PREFS_CURRENT_INDEX,appWidgetIds[i]),0);
updateDisplay(context,appWidgetId,getDataByKey(widgetDataStr,0));
}
editor.commit();
}
privateString[]getDataByKey(StringdataStr,intindex)
{
String[]strArr=dataStr.split("//|//|//|");
if(index<0)
index=0;
if(index>=strArr.length)
index=strArr.length-1;
strArr=strArr[index].split("=",2);
if(strArr.length==2)
returnstrArr;
returnnewString[]{"",""};
}
publicvoidupdateDisplay(Contextcontext,intappWidgetId,String[]playData)
{
RemoteViewsremoteView=newRemoteViews(context.getPackageName(),R.layout.appwidget);
remoteView.setTextViewText(R.id.widget_word,playData[0]);
remoteView.setTextViewText(R.id.widget_meaning,playData[1]);
remoteView.setOnClickPendingIntent(R.id.widget_back,makeControlPendingIntent(context,"back",appWidgetId));
remoteView.setOnClickPendingIntent(R.id.widget_next,makeControlPendingIntent(context,"next",appWidgetId));
AppWidgetManager.getInstance(context).updateAppWidget(appWidgetId,remoteView);
}
publicPendingIntentmakeControlPendingIntent(Contextcontext,Stringcommand,intappWidgetId)
{
Intentaction=newIntent();
action.setAction(ACTION_WIDGET_CONTROL);
action.putExtra(EXTRA_APPWIDGET_ID,appWidgetId);
Uridata=Uri.withAppendedPath(Uri.parse(URI_SCHEME+"://widget/id/#"+command),String.valueOf(appWidgetId));
action.setData(data);
return(PendingIntent.getBroadcast(context,0,action,PendingIntent.FLAG_ONE_SHOT));
}

这样widget就可以正常显示了，当然，现在还无法接受消息去处理事件，接下来注册接受器：

                    <receiver
            android:name=".widget"
             android:label="@string/app_name"
            >
            <intent-filter>
            <actionandroid:name="com.example.widget.WIDGET_CONTROL" />
            <dataandroid:scheme="widget"/>
            </intent-filter>
            <meta-dataandroid:name="android.appwidget.provider"
            android:resource="@xml/widget"
            />
            </receiver>
        
然后，处理不同命令：
                    publicvoidonReceive(Contextcontext,Intentintent) 
            if(ACTION_WIDGET_CONTROL.equals(action))
            {
            finalintappWidgetId=intent.getIntExtra(AppWidgetManager.EXTRA_APPWIDGET_ID,AppWidgetManager.INVALID_APPWIDGET_ID);
            if(appWidgetId!=AppWidgetManager.INVALID_APPWIDGET_ID)
            {
            StringcontrolType=intent.getData().getFragment();
            SharedPreferencesshared=context.getSharedPreferences(PREFS_NAME,0);
            intindex=shared.getInt(String.format(PREFS_CURRENT_INDEX,appWidgetId),0);
            intsize=Integer.parseInt(shared.getString(String.format(PREFS_DATA_SIZE,appWidgetId),"20"));
            if(controlType.equalsIgnoreCase("next"))
            {
            index++;
            if(index>=size)
            index=0;
            }
            elseif(controlType.equalsIgnoreCase("back"))
            {
            index--;
            if(index<0)
            index=size-1;
            }
            shared.edit().putInt(String.format(PREFS_CURRENT_INDEX,appWidgetId),index).commit();
            updateDisplay(
            context,
            appWidgetId,
            getDataByKey(shared.getString(String.format(PREFS_WIDGET_DATA,appWidgetId),""),index)
            );
            }
            }
            }
            最后，不能忘了收尾工作：
            publicvoidonDeleted(Contextcontext,int[]appWidgetIds){
            //TODOAuto-generatedmethodstub
            SharedPreferencesshared=context.getSharedPreferences(PREFS_NAME,0);
            for(intappWidgetId:appWidgetIds)
            {
            setAlarm(context,appWidgetId,-1);
            shared.edit().remove(String.format(PREFS_WIDGET_DATA,appWidgetId))
            .remove(String.format(PREFS_CURRENT_INDEX,appWidgetId))
            .commit();
            }
            super.onDeleted(context,appWidgetIds);
            }

更多相关文章

随机推荐