1案例技术要点

(1)创建TimeWidgetProvider继承于AppWidgetProvide类，并重写如下两个方法：

onDeleted(...)：当第一次向桌面添加Widgets的时候回调此方法

onEnabled(...)：当最后一个同类型Widgets实例被删除时回调此方法

(2)创建TimerService继承于Service类，用于获取系统当前日期与时间。

(3)通过获取AppWidgetManager实例将TimerService和TimeWidgetProvider关联起来。

2案例代码陈列

AndroidManifest.xml

strings.xml


    
        
     
      Lynn时间Widgets

main.xml

Widget布局文件：time_appwidget.xml

Widget背景文件：rectangle.xml

Widget显示内容提供者：TimeWidgetProvider.java

package cn.lynn.widgets;import android.appwidget.AppWidgetManager;import android.appwidget.AppWidgetProvider;import android.content.Context;import android.content.Intent;public class TimeWidgetProvider extends AppWidgetProvider {    // 当用户从桌面上删除widgets的时候回调此方法    @Override    public void onDeleted(Context context, int[] appWidgetIds) {            }        // 当第一次向桌面添加Widgets时回调此方法    @Override    public void onEnabled(Context context) {        context.startService(new Intent(context, TimerService.class));    }    // 当最后一个同类型Widgets实例被删除时回调此方法    @Override    public void onDisabled(Context context) {        context.stopService(new Intent(context, TimerService.class));    }    @Override    public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) {            }}

Widget服务管理类：TimerService.java

package cn.lynn.widgets;import java.text.SimpleDateFormat;import java.util.Date;import java.util.Timer;import java.util.TimerTask;import android.app.PendingIntent;import android.app.Service;import android.appwidget.AppWidgetManager;import android.content.ComponentName;import android.content.Intent;import android.net.Uri;import android.os.IBinder;import android.widget.RemoteViews;public class TimerService extends Service {    private Timer timer;        @Override    public void onCreate() {        super.onCreate();        timer = new Timer();        timer.schedule(new TimeUpdateWork(), 0, 1000);    }        private final class TimeUpdateWork extends TimerTask{        public void run() {            SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");            String time = dateFormat.format(new Date());            RemoteViews remoteView = new RemoteViews(getPackageName(), R.layout.time_appwidget);            remoteView.setTextViewText(R.id.textView, time);            // 拨号意图            PendingIntent pendingIntent = PendingIntent.getActivity(getApplicationContext(), 100,                    new Intent(Intent.ACTION_CALL, Uri.parse("tel:18777777777")), 0);            // 点击Widget拨打号码：18777777777            remoteView.setOnClickPendingIntent(R.id.textView, pendingIntent);            AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(getApplicationContext());            appWidgetManager.updateAppWidget(new ComponentName(getApplicationContext(), TimeWidgetProvider.class), remoteView);        }    }    @Override    public void onDestroy() {        timer.cancel();        timer = null;        super.onDestroy();    }    @Override    public IBinder onBind(Intent intent) {        return null;    }}