【Android】17.4 Activity與IntentService的綁定，activity綁定service

【Android】17.4 Activity與IntentService的綁定，activity綁定service

分類：C#、Android、VS2015；

建立日期：2016-03-03 一、簡介

本樣本通過AlarmManager類以固定的時間間隔調用服務（每隔2秒更新一次隨機產生的股票資料）。如果將此樣本的代碼改為定期調用一次Web服務，就能輕鬆實現股票線上更新的功能。 二、樣本3運行

本樣本在Android 4.4.2（API 19）中運行正常（右側螢幕中的資料會自動每2秒更新一次），但在Android 6.0（API 23）模擬器中AlarmManager不起作用，原因未知，所以這裡截取的是在Android 4.4.2模擬器中啟動並執行效果。

 

三、主要實現步驟

1、添加Json引用

有些股票資料是以JSON格式提供的，如果希望讀取JSON格式的資料，需要添加Json引用。

由於本例子實際並未使用它，所以不添加也可以。

具體添加辦法如下：滑鼠右擊項目中的“引用”，然後選擇Systm.Json：

2、添加Internet存取權限

股票一般都是通過Internet發布的，如果訪問股票的Web服務，還需要添加Internet存取權限（如果已經添加過就不用添加了）：

<uses-permission android:name="android.permission.INTERNET" />

當然，由於這個例子中並沒有真正訪問Internet，不添加這個許可權也可以。

3、添加ch1703_main.xml

<?xml version="1.0" encoding="utf-8"?><TextView xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:padding="15dp"    android:text="test" />

4、添加ch1703SockService.cs

using System;using System.Collections.Generic;using Android.App;using Android.Content;using Android.OS;namespace MyDemos.SrcDemos{    [Service]    [IntentFilter(new string[] { StocksUpdatedAction })]    public class ch1703StockService : IntentService    {        IBinder binder;        public List<Stock> Stocks { get; private set; }        public const string StocksUpdatedAction = "StocksUpdated";        List<string> stockSymbols = new List<string>() { "聯動A股", "深深B股", "宇平A股", "塔塔B股", "乖乖A股", "果果C股" };        Random r = new Random();        protected override void OnHandleIntent(Intent intent)        {            UpdateStocks();            var stocksIntent = new Intent(StocksUpdatedAction);            SendOrderedBroadcast(stocksIntent, null);        }        public override IBinder OnBind(Intent intent)        {            binder = new StockServiceBinder(this);            return binder;        }        //此處調用股票的Web服務返回結果，為簡化起見，這裡用隨機數直接返回了類比的結果        private void UpdateStocks()        {            Stocks = new List<Stock>();            for (int i = 0; i < stockSymbols.Count; i++)            {                Stocks.Add(new Stock() { Symbol = stockSymbols[i], LastPrice = r.Next(10, 151) });            }        }    }    public class StockServiceBinder : Binder    {        public ch1703StockService service { get; private set; }        public StockServiceBinder(ch1703StockService service)        {            this.service = service;        }    }    public class Stock    {        public string Symbol { get; set; }        public float LastPrice { get; set; }        public override string ToString()        {            return string.Format("[Stock: Symbol={0}, LastPrice={1}]", Symbol, LastPrice);        }    }}

5、添加ch1703MainActivity.cs

注意該類繼承自ListActivity。

using Android.App;using Android.Content;using Android.OS;using Android.Widget;namespace MyDemos.SrcDemos{    [Activity(Label = "【例17-3】綁定到IntentService")]    public class ch1703MainActivity : ListActivity    {        bool isBound = false;        StockServiceBinder binder;        StockServiceConnection stockServiceConnection;        StockReceiver stockReceiver;        Intent stockServiceIntent;        protected override void OnCreate(Bundle savedInstanceState)        {            base.OnCreate(savedInstanceState);            stockReceiver = new StockReceiver(this);            stockServiceIntent = new Intent(ch1703StockService.StocksUpdatedAction);            stockServiceConnection = new StockServiceConnection(this);            BindService(stockServiceIntent, stockServiceConnection, Bind.AutoCreate);            var intentFilter = new IntentFilter();            intentFilter.AddAction(ch1703StockService.StocksUpdatedAction);            intentFilter.Priority = (int)IntentFilterPriority.HighPriority;            RegisterReceiver(stockReceiver, intentFilter);            var alarm = (AlarmManager)GetSystemService(AlarmService);            var a = PendingIntent.GetService(                this, 0, stockServiceIntent, PendingIntentFlags.UpdateCurrent);            //每2秒更新一次            alarm.SetRepeating(AlarmType.Rtc, 0, 2000, a);        }        protected override void OnDestroy()        {            if (isBound == true)            {                UnbindService(stockServiceConnection);                isBound = false;            }            UnregisterReceiver(stockReceiver);            base.OnDestroy();        }        private void UpdateStocks()        {            if (isBound)            {                var stocks = binder.service.Stocks;                if (stocks != null)                {                    ListAdapter = new ArrayAdapter<Stock>(this,                        Resource.Layout.ch1703_main, stocks);                }            }        }        private class StockReceiver : BroadcastReceiver        {            ch1703MainActivity activity;            public StockReceiver(ch1703MainActivity activity)            {                this.activity = activity;            }            public override void OnReceive(Context context, Intent intent)            {                activity.UpdateStocks();            }        }        private class StockServiceConnection : Java.Lang.Object, IServiceConnection        {            ch1703MainActivity activity;            public StockServiceConnection(ch1703MainActivity activity)            {                this.activity = activity;            }            public void OnServiceConnected(ComponentName name, IBinder service)            {                var stockServiceBinder = service as StockServiceBinder;                if (stockServiceBinder != null)                {                    var binder = (StockServiceBinder)service;                    activity.binder = binder;                    activity.isBound = true;                }            }            public void OnServiceDisconnected(ComponentName name)            {                activity.isBound = false;            }        }    }}