Android学习10-Android组件通讯 (5) Service

Service基本组成：

在Android系统开发中，Service是一个重要的组成部分，如果某些程序是不希望用户看见的，那么可以将这些程序定义在Service中，这样就可以完成程序的后台运行（也可以在不现实界面的形式下运行），即Service实际上相当于是一个没有图形界面的Activity程序，而且当用户要执行某些操作需要进行跨进程访问时，也可以用Service来完成。

Service是一个没有UI界面的操作组件，主要功能是为Activity程序提供一些必要的支持，如手机中的Mp3播放软件等，当回到主界时这些组件依然可以运行，这些就属于Service的功能，在开发时，用户只需要继承android.app.Service类就可以完成Service程序的开发。

Service的生命周期控制方法及常量：

Activity操作Service的方法

范例：

定义用户的Service组件：MyServiceUtil.java

package com.iflytek.demo;import android.app.Service;import android.content.Intent;import android.os.IBinder;public class MyServiceUtil extends Service {	@Override	public IBinder onBind(Intent intent) {// 绑定Activity		return null; // 此处暂时不做任何的处理	}	@Override	public void onCreate() {// 创建时调用		System.out.println("*** Service onCreate()");	}	@Override	public void onDestroy() {// 销毁时调用		System.out.println("*** Service onDestroy()");	}	@Override	public int onStartCommand(Intent intent, int flags, int startId) {// 开始Service		System.out.println("*** Service onStartCommand");		return Service.START_CONTINUATION_MASK; // 继续执行Service	}}

与Activity最大的区别在于此处只是提供了一些后台的操作。

Service01Activity.java

package com.iflytek.demo;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;public class Service01Activity extends Activity {	private Button start;	private Button stop;	/** Called when the activity is first created. */	@Override	public void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		super.setContentView(R.layout.main);		this.start = (Button) super.findViewById(R.id.start);		this.stop = (Button) super.findViewById(R.id.stop);		this.start.setOnClickListener(new StartOnClickListenerImpl());		this.stop.setOnClickListener(new StopOnClickListenerImpl());	}	private class StartOnClickListenerImpl implements OnClickListener {		@Override		public void onClick(View v) {			Service01Activity.this.startService(new Intent(					Service01Activity.this, MyServiceUtil.class));		}	}	private class StopOnClickListenerImpl implements OnClickListener {		@Override		public void onClick(View v) {			Service01Activity.this.stopService(new Intent(					Service01Activity.this, MyServiceUtil.class));		}	}}

在AndroidManifest.xml中添加：

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

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运行结果：

点击“启动Service”按钮：10-28 20:40:18.225: I/System.out(7081): *** Service onCreate()10-28 20:40:18.230: I/System.out(7081): *** Service onStartCommand重复点击“启动Service”按钮：10-28 20:42:10.875: I/System.out(7331): *** Service onStartCommand单击“结束Service”按钮：10-28 20:42:52.860: I/System.out(7353): *** Service onDestroy()

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绑定Service:

当一个Service程序启动之后，如果没有出现意外且调用stopService()方法，则将会一直留在手机的服务之中，如果希望由Activity启动的Service程序可以在Activity程序结束后自动结束，则可以将Activity和Service程序进行绑定。

ServiceConnection接口定义方法

所以我们可以发现Service与ServiceConnection的联系，默认情况下，当一个Activity程序启动Service之后，该Service程序是在后台独自运行的，与前台的Activity就没有关系了，而使用ServiceConnection就表示该Service永远要和这个Activity程序绑定在一期，不再是独立运行了。

MyServiceUtil.java

package com.iflytek.demo;import android.app.Service;import android.content.Intent;import android.os.Binder;import android.os.IBinder;public class MyServiceUtil extends Service {	private IBinder myBinder = new Binder() {		@Override		public String getInterfaceDescriptor() {// 取得接口描述信息			return "MyServiceUitl Class ..";// 返回Service类的名称		}	};	@Override	public IBinder onBind(Intent intent) {// 绑定时触发		System.out.println("*** Service onBind()");		return this.myBinder; // 此处暂时不做任何的处理	}	@Override	public void onRebind(Intent intent) {// 重新绑定时触发		System.out.println("*** Service onRebind()");		super.onRebind(intent);	}	@Override	public boolean onUnbind(Intent intent) {// 接触绑定时触发		System.out.println("*** Service onUnbind()");		return super.onUnbind(intent);	}	@Override	public void onCreate() {// 创建时触发		System.out.println("*** Service onCreate()");	}	@Override	public void onDestroy() {// 销毁时触发		System.out.println("*** Service onDestroy()");	}	@Override	public int onStartCommand(Intent intent, int flags, int startId) {// 启动时触发		System.out.println("*** Service onStartCommand");		return Service.START_CONTINUATION_MASK; // 继续执行	}}

Service02_Activity.java

package com.iflytek.demo;import android.app.Activity;import android.content.ComponentName;import android.content.Context;import android.content.Intent;import android.content.ServiceConnection;import android.os.Bundle;import android.os.IBinder;import android.os.RemoteException;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;public class Service02_Activity extends Activity {	private Button start;	private Button stop;	private Button bind;	private Button unbind;	private ServiceConnection serviceConnection = new ServiceConnection() {		@Override		public void onServiceConnected(ComponentName name, IBinder service) {// 连接到Service			try {				System.out.println("### Service Connect Success . service = "						+ service.getInterfaceDescriptor());			} catch (RemoteException e) {			}		}		@Override		public void onServiceDisconnected(ComponentName name) {// 与Service断开连接			System.out.println("### Service Connect Failure.");		}// 接受服务状态	};	/** Called when the activity is first created. */	@Override	public void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		super.setContentView(R.layout.main);		this.start = (Button) super.findViewById(R.id.start);		this.stop = (Button) super.findViewById(R.id.stop);		this.bind = (Button) super.findViewById(R.id.bind);		this.unbind = (Button) super.findViewById(R.id.unbind);		this.start.setOnClickListener(new StartOnClickListenerImpl());		this.stop.setOnClickListener(new StopOnClickListenerImpl());		this.bind.setOnClickListener(new BindOnClickListenerImpl());		this.unbind.setOnClickListener(new UnbindOnClickListenerImpl());	}	private class StartOnClickListenerImpl implements OnClickListener {		@Override		public void onClick(View v) {			Service02_Activity.this.startService(new Intent(// 启动Service					Service02_Activity.this, MyServiceUtil.class));		}	}	private class StopOnClickListenerImpl implements OnClickListener {		@Override		public void onClick(View v) {			Service02_Activity.this.stopService(new Intent(// 停止Service					Service02_Activity.this, MyServiceUtil.class));		}	}	private class BindOnClickListenerImpl implements OnClickListener {		@Override		public void onClick(View v) {// 绑定Service			Service02_Activity.this.bindService(new Intent(					Service02_Activity.this, MyServiceUtil.class),					Service02_Activity.this.serviceConnection,					Context.BIND_AUTO_CREATE);		}	}	private class UnbindOnClickListenerImpl implements OnClickListener {		@Override		public void onClick(View v) {// 取消Service			Service02_Activity.this					.unbindService(Service02_Activity.this.serviceConnection);		}	}}

运行结果：

（1）	单击“启动Service”按钮：10-28 21:42:10.950: I/System.out(8093): *** Service onCreate()10-28 21:42:10.950: I/System.out(8093): *** Service onStartCommand（2）	单击“绑定Service”按钮：10-28 21:43:55.620: I/System.out(8237): *** Service onBind()10-28 21:43:55.640: I/System.out(8237): ### Service Connect Success . service = MyServiceUitl Class ..（3）	取消1，2，直接单击“绑定Service”按钮：10-28 21:48:31.200: I/System.out(8638): *** Service onCreate()10-28 21:48:31.205: I/System.out(8638): *** Service onBind()10-28 21:48:31.225: I/System.out(8638): ### Service Connect Success . service = MyServiceUitl Class ..（4）	不单击“停止”，直接退出Activity程序10-28 21:50:06.565: I/System.out(8708): *** Service onUnbind()当服务启动后，实际上就在手机系统的后台了，因为Activity程序被关闭后，与Service连接的Activity就消失了，所以此处要解除与Activity程序的绑定，但服务不会销毁。（5）	返回Activity程序，单击 “绑定Service”按钮：10-28 21:51:31.225: I/System.out(8638): ### Service Connect Success . service = MyServiceUitl Class ..当用户再次回到Activity程序之后，则可以重新取得一个Activity与Service之间绑定的ServiceConnect接口对象（6）	单击“解除绑定Service”按钮：10-28 21:52:06.565: I/System.out(8708): *** Service onUnbind()（7）	单击“停止Service”按钮：10-28 21:52:06.570: I/System.out(8708): *** Service onDestroy()

如果没有服务与Activity进行绑定而又调用了解除绑定操作，则会出现错误，所以，在解除绑定之前必须要增加一个判断，判断一个Activity是否和一个Service绑定在一期，如果绑定在一起，才可以使用unbindService()方法解除绑定。
但是遗憾的是，在Android中并没有提供这样的一个判断方法，所以一般的做法是定义一个标记性的操作接口，而后台Activity中判断此接口对象是否为null来决定是否绑定了Service。

定义一个标记性接口IService.java

package com.iflytek.demo;/** *  * @author xdwang  * * @create 2012-10-28 下午10:02:23 *  * @email:[email protected] *  * @description 标记性接口 * */public interface IService {}

定义服务类MyServiceUtil.java

package com.iflytek.demo;import android.app.Service;import android.content.Intent;import android.os.Binder;import android.os.IBinder;public class MyServiceUtil extends Service {	private IBinder myBinder = new BinderImpl();	@Override	public IBinder onBind(Intent intent) {		System.out.println("*** Service onBind()");		return this.myBinder; // 此处暂时不做任何的处理	}	class BinderImpl extends Binder implements IService {//这里多实现一个接口		@Override		public String getInterfaceDescriptor() {			return "MyServiceUitl Class ..";		}	}}

BinderImpl多实现了一个IService接口，这样以后就可以通过ServiceConnection中的onServiceConnected()方法取得此IService子类对象

Service03_Activity.java

package com.iflytek.demo;import android.app.Activity;import android.content.ComponentName;import android.content.Context;import android.content.Intent;import android.content.ServiceConnection;import android.os.Bundle;import android.os.IBinder;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import com.iflytek.demo.MyServiceUtil.BinderImpl;public class Service03_Activity extends Activity {	private Button bind;	private Button unbind;	private IService service = null;	private ServiceConnection serviceConnection = new ServiceConnectionImpl();	private class ServiceConnectionImpl implements ServiceConnection {		@Override		public void onServiceConnected(ComponentName name, IBinder service) {			Service03_Activity.this.service = (BinderImpl) service;			// BinderImpl是IBinder接口的子类，所以将IBinder向下转型为BinderImpl类			// 而后通过此类对象为Service接口实例化		}		@Override		public void onServiceDisconnected(ComponentName name) {		}	}	/** Called when the activity is first created. */	@Override	public void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		super.setContentView(R.layout.main);		this.bind = (Button) super.findViewById(R.id.bind);		this.unbind = (Button) super.findViewById(R.id.unbind);		this.bind.setOnClickListener(new BindOnClickListenerImpl());		this.unbind.setOnClickListener(new UnbindOnClickListenerImpl());	}	private class BindOnClickListenerImpl implements OnClickListener {		@Override		public void onClick(View v) {			Service03_Activity.this.bindService(new Intent(					Service03_Activity.this, MyServiceUtil.class),					Service03_Activity.this.serviceConnection,					Context.BIND_AUTO_CREATE);		}	}	private class UnbindOnClickListenerImpl implements OnClickListener {		@Override		public void onClick(View v) {			if (Service03_Activity.this.service != null) {				Service03_Activity.this						.unbindService(Service03_Activity.this.serviceConnection);				Service03_Activity.this.service = null;			}		}	}}

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操作系统服务：

在Android系统中也提供了一些系统服务，为了方便操作这些系统服务，在android.content.Context类中将所有的系统服务名称以常量的形式进行了绑定，用户使用时直接利用getSystemService()方法指定好服务的名称就可以取得。Context类中定义的系统服务：

具体可以查询相关Android文档。

一、系统剪贴板服务

Service04_Activity.java

package com.iflytek.demo;import android.app.Activity;import android.content.Context;import android.os.Bundle;import android.text.ClipboardManager;public class Service04_Activity extends Activity {	/** Called when the activity is first created. */	@Override	public void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		super.setContentView(R.layout.main);		ClipboardManager clipboardManager = (ClipboardManager) super				.getSystemService(Context.CLIPBOARD_SERVICE); // 取得剪贴板服务		clipboardManager.setText("XDWANG");//设置剪贴板中的内容	}}

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一、取得正在进行的进程信息

在Android系统中可以通过super.getSystemService()方法取得android.app.ActivityManager，此类的常用方法有：

1、取得正在运行的Activity程序：ActivityManager.RunningTaskInfo

Service05_Activity.java

package com.iflytek.demo;import java.util.ArrayList;import java.util.Iterator;import java.util.List;import android.app.Activity;import android.app.ActivityManager;import android.content.Context;import android.os.Bundle;import android.widget.ArrayAdapter;import android.widget.ListAdapter;import android.widget.ListView;public class Service05_Activity extends Activity {	private ListView tasklist = null;	private ListAdapter adapter = null;	private List<String> all = new ArrayList<String>();	private ActivityManager activityManager = null;	private List<ActivityManager.RunningTaskInfo> allTaskInfo;	/** Called when the activity is first created. */	@Override	public void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		super.setContentView(R.layout.main);		this.tasklist = (ListView) super.findViewById(R.id.tasklist);		this.activityManager = (ActivityManager) super				.getSystemService(Context.ACTIVITY_SERVICE);		this.listActivity();	}	private void listActivity() {		this.allTaskInfo = this.activityManager.getRunningTasks(30); // 返回30条		Iterator<ActivityManager.RunningTaskInfo> iterInfo = this.allTaskInfo				.iterator();		while (iterInfo.hasNext()) {			ActivityManager.RunningTaskInfo task = iterInfo.next();			this.all.add("【ID = " + task.id + " 】 "					+ task.baseActivity.getClassName());		}		this.adapter = new ArrayAdapter<String>(this,				android.R.layout.simple_list_item_1, this.all);		this.tasklist.setAdapter(this.adapter);	}}

添加权限：

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

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2、取得后台运行的服务信息：ActivityManager.RunningServiceInfo

Service06_Activity.java

package com.iflytek.demo;import java.util.ArrayList;import java.util.Iterator;import java.util.List;import android.app.Activity;import android.app.ActivityManager;import android.content.Context;import android.os.Bundle;import android.widget.ArrayAdapter;import android.widget.ListAdapter;import android.widget.ListView;public class Service06_Activity extends Activity {	private ListView tasklist = null;	private ListAdapter adapter = null;	private List<String> all = new ArrayList<String>();	private ActivityManager activityManager = null;	private List<ActivityManager.RunningServiceInfo> allTaskInfo;	/** Called when the activity is first created. */	@Override	public void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		super.setContentView(R.layout.main);		this.tasklist = (ListView) super.findViewById(R.id.tasklist);		this.activityManager = (ActivityManager) super				.getSystemService(Context.ACTIVITY_SERVICE);		this.listActivity();	}	private void listActivity() {		this.allTaskInfo = this.activityManager.getRunningServices(30);		Iterator<ActivityManager.RunningServiceInfo> iterInfo = this.allTaskInfo				.iterator();		while (iterInfo.hasNext()) {			ActivityManager.RunningServiceInfo service = iterInfo.next();			this.all.add("【ID = " + service.pid + " 】 " + service.process);		}		this.adapter = new ArrayAdapter<String>(this,				android.R.layout.simple_list_item_1, this.all);		this.tasklist.setAdapter(this.adapter);	}}

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3、取得所有的正在运行进程信息：ActivityManager.RunningAppProcessInfo

Service07_Activity.java

package com.iflytek.demo;import java.util.ArrayList;import java.util.Iterator;import java.util.List;import android.app.Activity;import android.app.ActivityManager;import android.content.Context;import android.os.Bundle;import android.widget.ArrayAdapter;import android.widget.ListAdapter;import android.widget.ListView;public class Service07_Activity extends Activity {	private ListView tasklist = null;	private ListAdapter adapter = null;	private List<String> all = new ArrayList<String>();	private ActivityManager activityManager = null;	private List<ActivityManager.RunningAppProcessInfo> allTaskInfo;	/** Called when the activity is first created. */	@Override	public void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		super.setContentView(R.layout.main);		this.tasklist = (ListView) super.findViewById(R.id.tasklist);		this.activityManager = (ActivityManager) super				.getSystemService(Context.ACTIVITY_SERVICE);		this.listActivity();	}	private void listActivity() {		this.allTaskInfo = this.activityManager.getRunningAppProcesses();		Iterator<ActivityManager.RunningAppProcessInfo> iterInfo = this.allTaskInfo				.iterator();		while (iterInfo.hasNext()) {			ActivityManager.RunningAppProcessInfo app = iterInfo.next();			this.all.add("【ID = " + app.pid + " 】 " + app.processName);		}		this.adapter = new ArrayAdapter<String>(this,				android.R.layout.simple_list_item_1, this.all);		this.tasklist.setAdapter(this.adapter);	}}

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三、取得手机网络信息

在Android中，用户可以直接使用getSystemService()方法通过Context.TELEPHONY_SERVICE取得手机网络的相关信息，android.telephony.TelephonyManager

Service08_Activity.java

package com.iflytek.demo;import java.util.ArrayList;import java.util.List;import android.app.Activity;import android.content.Context;import android.os.Bundle;import android.telephony.TelephonyManager;import android.widget.ArrayAdapter;import android.widget.ListAdapter;import android.widget.ListView;public class Service08_Activity extends Activity {	private ListView infolist = null;	private ListAdapter adapter = null;	private List<String> all = new ArrayList<String>();	private TelephonyManager manager = null;	/** Called when the activity is first created. */	@Override	public void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		super.setContentView(R.layout.main);		this.infolist = (ListView) super.findViewById(R.id.infolist);		this.manager = (TelephonyManager) super				.getSystemService(Context.TELEPHONY_SERVICE); // 电话服务		this.list();	}	private void list() { // 列出一些信息		this.all.add(this.manager.getLine1Number() == null ? "没有手机号码" : "手机号码："				+ this.manager.getLine1Number());		this.all.add(this.manager.getNetworkOperatorName() == null ? "没有移动服务商"				: "移动服务商：" + this.manager.getNetworkOperatorName());		if (this.manager.getPhoneType() == TelephonyManager.NETWORK_TYPE_CDMA) {			this.all.add("移动网络：CDMA");		} else if (this.manager.getPhoneType() == TelephonyManager.NETWORK_TYPE_GPRS) {			this.all.add("移动网络：GPRS");		} else {			this.all.add("移动网络：未知");		}		if (this.manager.getNetworkType() == TelephonyManager.PHONE_TYPE_GSM) {			this.all.add("网络类型：GSM");		} else if (this.manager.getNetworkType() == TelephonyManager.PHONE_TYPE_CDMA) {			this.all.add("网络类型：CDMA");		} else {			this.all.add("网络类型：未知");		}		this.all.add("是否漫游：" + (this.manager.isNetworkRoaming() ? "漫游" : "非漫游"));		this.adapter = new ArrayAdapter<String>(this,				android.R.layout.simple_list_item_1, this.all);		this.infolist.setAdapter(this.adapter);	}}

添加权限：

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

四、取得WiFi操作

在Android中，用户可以直接使用getSystemService()方法通过Context.WIFI_SERVICE取得手机网络的相关信息，android.net.wifi.WifiManager

Service09_Activity.java

package com.iflytek.demo;import android.app.Activity;import android.content.Context;import android.net.wifi.WifiManager;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.TextView;public class Service09_Activity extends Activity {	private Button open = null;	private Button close = null;	private Button check = null;	private TextView msg = null;	private WifiManager wifiManager = null;	/** Called when the activity is first created. */	@Override	public void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		super.setContentView(R.layout.main);		this.open = (Button) super.findViewById(R.id.open);		this.close = (Button) super.findViewById(R.id.close);		this.check = (Button) super.findViewById(R.id.check);		this.msg = (TextView) super.findViewById(R.id.msg);		this.wifiManager = (WifiManager) super				.getSystemService(Context.WIFI_SERVICE);		this.open.setOnClickListener(new OnClickListener() {			@Override			public void onClick(View v) {				Service09_Activity.this.wifiManager.setWifiEnabled(true); // 启用wifi				Service09_Activity.this.msg.setText("打开WIFI，状态："						+ Service09_Activity.this.wifiManager.getWifiState());			}		});		this.close.setOnClickListener(new OnClickListener() {			@Override			public void onClick(View v) {				Service09_Activity.this.wifiManager.setWifiEnabled(false); // 启用wifi				Service09_Activity.this.msg.setText("打开WIFI，状态："						+ Service09_Activity.this.wifiManager.getWifiState());			}		});		this.check.setOnClickListener(new OnClickListener() {			@Override			public void onClick(View v) {				Service09_Activity.this.msg.setText("检查WIFI，状态："						+ Service09_Activity.this.wifiManager.getWifiState());			}		});	}}

添加权限：

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

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