Android学习笔记_33_Widget时钟（MetaData）

Widgets在文档docs\guide\topics\appwidgets\index.html下

     Android中AppWidget的分析与应用：AppWidgetProvider

　　一、在 AndroidManifest.xml文件中配置Widgets：

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="com.example.widget"

    android:versionCode="1"

    android:versionName="1.0" >



    <uses-sdk

        android:minSdkVersion="8"

        android:targetSdkVersion="17" />



    <application

        android:allowBackup="true"

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme" >

        <receiver android:name=".TimeWidgetProvider" >

            <intent-filter>

                <action android:name="android.appwidget.action.APPWIDGET_UPDATE" />

            </intent-filter>

            <meta-data

                android:name="android.appwidget.provider"

                android:resource="@xml/timewidget_info" />

        </receiver>

        <service android:name=".TimerService"></service>

    </application>



</manifest>

　　二、在项目的res目录下建立xml目录，并且创建 timewidget_info.xml 文件，内容如下：

<?xml version="1.0" encoding="UTF-8"?>

<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"

    android:initialLayout="@layout/time_appwidget"

    android:minHeight="40dp"

    android:minWidth="40dp"

    android:updatePeriodMillis="0" />

　　三、在layout文件夹下建立文件time_appwidget.xml：

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical" 

    android:background="@drawable/rectangle"

    >

    

    <TextView 

         android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:id="@+id/textView"

        android:text="current time"

        />



</LinearLayout>

　　四、在drawable文件夹下建立rectangle.xml文件(这部可以省略，主要是为了美化TextView控件，渐变效果)：

<?xml version="1.0" encoding="utf-8"?>

<shape xmlns:android="http://schemas.android.com/apk/res/android"

    android:shape="rectangle" >



    <!-- 设置弧度 -->

    <corners android:radius="9dp" />



    <gradient

        android:angle="270"

        android:endColor="#5EADF4"

        android:startColor="#B3F0FF" />



    <padding

        android:bottom="5dp"

        android:left="5dp"

        android:right="5dp"

        android:top="5dp" />



    <stroke

        android:dashGap="1dp"

        android:dashWidth="10dp"

        android:width="6dp"

        android:color="#0000FF" />



</shape>

　　五、后台代码实现：

package com.example.widget;



import android.appwidget.AppWidgetManager;

import android.appwidget.AppWidgetProvider;

import android.content.Context;

import android.content.Intent;



public class TimeWidgetProvider extends AppWidgetProvider {



    @Override

    public void onUpdate(Context context, AppWidgetManager appWidgetManager,

            int[] appWidgetIds) {

        super.onUpdate(context, appWidgetManager, appWidgetIds);

    }



    //当一个Widgets时会被调用

    public void onDeleted(Context context, int[] appWidgetIds) {

        // TODO Auto-generated method stub

        super.onDeleted(context, appWidgetIds);

    }



    //第一次往桌面添加Widgets时会被调用，之后添加同类型Widgets不会被调用

    public void onEnabled(Context context) {

        context.startService(new Intent(context, TimerService.class));

    }



    //从桌面上删除最后一个Widgets时会被调用

    public void onDisabled(Context context) {

        context.stopService(new Intent(context, TimerService.class));

    }



}

 

package com.example.widget;



import java.text.SimpleDateFormat;

import java.util.Date;

import java.util.Timer;

import java.util.TimerTask;



import android.annotation.SuppressLint;

import android.app.Service;

import android.appwidget.AppWidgetManager;

import android.content.ComponentName;

import android.content.Intent;

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 MyTimerTask(), 0, 1000);

    }

    private final class MyTimerTask extends TimerTask{

        @SuppressLint("SimpleDateFormat")

        @Override

        public void run() {

            SimpleDateFormat sdf= new SimpleDateFormat("hh:mm:ss");

            String time = sdf.format(new Date());

            //获取Widgets管理器

              AppWidgetManager widgetManager =AppWidgetManager.getInstance(getApplicationContext());

            //widgetManager所操作的Widget对应的远程视图即当前Widget的layout文件

              RemoteViews remoteView = new RemoteViews(getPackageName(), R.layout.time_appwidget);

            remoteView.setTextViewText(R.id.textView, time);

            //当点击Widgets时触发的世界

            //remoteView.setOnClickPendingIntent(viewId, pendingIntent)

            ComponentName componentName = new  ComponentName(getApplicationContext(),TimeWidgetProvider.class);

            widgetManager.updateAppWidget(componentName, remoteView);

        }

    }



    @Override

    public void onDestroy() {

        timer.cancel();

        timer=null;

        super.onDestroy();

    }



    @Override

    public IBinder onBind(Intent intent) {

        return null;

    }



}