Android筆記 - 設計appwidget

設計一個在平板桌面上跑的小時鐘,用thread每秒更新一次時間 據上一次程式,這小工具是在桌面上來顯示因此,新增Project時不選Create Activity,此次轉換到MacBook Air機器上開發(因為模擬器比較正常一些)

1.新增Project名稱叫widget_clock(File->New->Project->Android Project->Next->Project Name->Next->Android 3.0->
不選Create Activity
Pockage Name :test.clock_widget

2.新增appwidget-provider（File->New->Other->Android XML File->Next->Resource Type選 AppWidget Provider)(如下圖)

產生好xml filfe(clock_widge.xml)後,修改下面紅色字體部份(亮藍色背景)
說明:

android:updatePeriodMillis="0"代表只讓appwidget更新一次,我要自行用thread來更新

android:initialLayout="@layout/main" 是指initialLayout指定你layout佈局的xml(main)


clock_widge.xml File:

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

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

    android:minWidth="294dp"

    android:minHeight="150dp"

    android:updatePeriodMillis="0"

    android:initialLayout="@layout/main" 

     >

</appwidget-provider>

3.修改main.xml的內容加入下面紅色字體部份(亮藍色背景)
說明:

android:id="@+id/now設定view id


main.xml File:

<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:id="@+id/now"

    android:gravity="center"

    android:textColor="@android:color/white"

    android:textSize="32sp"

    android:layout_width="fill_parent" 

    android:layout_height="fill_parent" 

    android:text="@string/hello"

    />

LinearLayout>

4.修改AndroidManifest.xml加入下面紅色字體部份(亮藍色背景)

說明:
<receiver android:name=".Clock_widget" >
<service android:enabled="true" android:name=".Clock_widget" />

同時指定receiver,service為.Clock_widget(java class,這是要新增class更新appwidget的)

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

指定動作方式APPWIDGET_UPDATE

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

指定resource="@xml/clock_widge" (步驟1新增的xml)

AndroidManifest.xml File:

<xml version="1.0" encoding="utf-8"?>

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

    package="test.widget_clock"

    android:versionCode="1"

    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="10" />

    <application

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name" >

         <receiver android:name=".Clock_widget" >

            <intent-filter>

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

            </intent-filter>

            <meta-data android:name="android.appwidget.provider"

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

        </receiver>

         <service android:enabled="true" android:name=".Clock_widget" />

        

            

            

    application>

manifest>

5.新增class(Clock_widget)File->New->Class


說明:

Clock_widget.java內容如下

此class繼承了AppWidgetProvider並覆寫更新onUpdate程序,Handler是要工作的內容,用thread來時時送出handler訊息
updateViews.setTextViewText(R.id.now, str ); 
updateViews.setTextColor(R.id.now, -1);
這兩行now對應到main.xml所設的id

Clock_widget.java File:

package test.widget_clock;

import java.util.Calendar;

import android.appwidget.AppWidgetManager;

import android.appwidget.AppWidgetProvider;

import android.content.Context;

import android.os.Handler;

import android.os.Message;

import android.widget.RemoteViews;

public class Clock_widget extends AppWidgetProvider{

public Handler c_Handler;

public Context cc;

public int[] aapid;

public AppWidgetManager appw;

private Thread c_Thread;

public Calendar c_Calendar; //日曆

private int c_Minutes; //分

private int c_Hour; //時

private int c_Second; //秒

private String str;

@Override

public void onUpdate(Context context,AppWidgetManager appWidgetManager, int[] appWidgetIds) {

cc=context;

aapid=appWidgetIds;

appw=appWidgetManager;

c_Handler =new Handler(){

public void handleMessage(Message msg){

long time=System.currentTimeMillis();

final Calendar c_Calendar = Calendar.getInstance();

c_Calendar.setTimeInMillis(time);

c_Hour=c_Calendar.get(Calendar.HOUR);

c_Minutes=c_Calendar.get(Calendar.MINUTE);

c_Second=c_Calendar.get(Calendar.SECOND);

str="現在時間 "+c_Hour+":"+c_Minutes+":"+c_Second;

RemoteViews updateViews = new RemoteViews( cc.getPackageName(), R.layout.main);

updateViews.setTextViewText(R.id.now, str );

updateViews.setTextColor(R.id.now, -1);

appw.updateAppWidget(aapid, updateViews);

}

};

//產執行續物件

c_Thread = new clock_Thread();

//啟動執行續

c_Thread.start();

}//onupdate

//thread class

class clock_Thread extends Thread{

public void run(){

super.run();

try{

do{

Thread.sleep(1000);

Message m=new Message();

// 將Message物件送入MessageQueue裡

c_Handler.sendMessage(m);

}while(true);

}catch (Exception e) {

// handle exception

}//cttch

}//run

}//thread

}//Clock_widget class

5.模擬器上跑的結果