我们知道，Android有四大组件，分别是Activity,Content Provider , Broadcast Receiver 和今天我们要用到的Service。

我们说Service是看不见摸不着的，是因为它对用户是不可见的，Service作为四大组件之一，它的职责是工作在后台，处理

一些比较耗时的操作（如下载，播放媒体文件，检测版本更新和日志输出等)。

就像学习Activity组件一样，要想熟悉Service,必须知道它的整个工作流程，即它的生命周期(Life-cycle)，下面是官网给

出的一个具体图例：

 

 

 

从图例我们可以知道，Service有两种启动方式，第一种是调用Context.startService()方法，

另外一种是调用Context.bindService().

对于第一种调用方法，系统会先调用onCreate()方法，负责初始化工作，然后调用onStart()方法，

启动Service，如果程序显示调用Context.stopService()方法或者Service自身调用stopSelf()方法

或者stopSelfResult()方法，都会调用onDestroy()方法，结束该服务，另外需要注意的是，调用者

和Service是没有关联的，也就是说，如果调用者退出了，并不会影响服务的运行。

对于第二种方式，调用方法是Context.bindService()，系统会先调用onCreate()方法，然后调用onBind()

方法，和调用者绑定，如果调用者退出，服务会调用onDestroy()方法结束自己的运行。

 

学完了一个东西，如果趁热打铁，自己编写一个demo,肯定会加深对该知识点的理解。

废话少说，下面给出一个电话录音的例子：

 

首先，也是最重要的，关于权限的声明:

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01.<!-- 电话状态监听权限 --> 
02.<uses-permission android:name="android.permission.READ_PHONE_STATE" /> 
03.<!-- 开机广播权限 --> 
04.<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" /> 
05. 
06.<!-- 音频刻录权限 --> 
07.<uses-permission android:name="android.permission.RECORD_AUDIO" /> 
08.<!-- 写入权限 --> 
09.<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> 
    <!-- 电话状态监听权限 -->
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
    <!-- 开机广播权限 -->
    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

    <!-- 音频刻录权限 -->
    <uses-permission android:name="android.permission.RECORD_AUDIO" />
    <!-- 写入权限 -->
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
接下来是编写一个简单的Activity,用来启动Broadcast Receiver组件。

 

 

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01.package com.example.service_record_call; 
02. 
03.import android.app.Activity; 
04.import android.content.Intent; 
05.import android.os.Bundle; 
06. 
07.public class MainActivity extends Activity { 
08. 
09.    @Override 
10.    public void onCreate(Bundle savedInstanceState) { 
11.        super.onCreate(savedInstanceState); 
12.        setContentView(R.layout.activity_main); 
13.         
14.        Intent receiver = new Intent("zjut.tsw.receiver"); 
15.        this.sendBroadcast(receiver); 
16.    } 
17. 
18.     
19.} 
package com.example.service_record_call;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;

public class MainActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
       
        Intent receiver = new Intent("zjut.tsw.receiver");
        this.sendBroadcast(receiver);
    }

   
}

然后是编写一个简单的Broadcast Receiver，负责启动Service

 

 

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01.package com.example.service_record_call; 
02. 
03.import android.content.BroadcastReceiver; 
04.import android.content.Context; 
05.import android.content.Intent; 
06. 
07.public class MyBroadcastReceiver extends BroadcastReceiver { 
08. 
09.    @Override 
10.    public void onReceive(Context context, Intent intent) { 
11.        Intent service = new Intent(context,PhoneListenerService.class); 
12.        context.startService(service); 
13.    } 
14. 
15.} 
package com.example.service_record_call;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;

public class MyBroadcastReceiver extends BroadcastReceiver {

 @Override
 public void onReceive(Context context, Intent intent) {
  Intent service = new Intent(context,PhoneListenerService.class);
  context.startService(service);
 }

}

接下来是编写核心Service.

 

 

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01.package com.example.service_record_call; 
02. 
03.import java.io.File; 
04. 
05.import android.app.Service; 
06.import android.content.Context; 
07.import android.content.Intent; 
08.import android.media.MediaRecorder; 
09.import android.os.Environment; 
10.import android.os.IBinder; 
11.import android.telephony.PhoneStateListener; 
12.import android.telephony.TelephonyManager; 
13.import android.util.Log; 
14. 
15.public class PhoneListenerService extends Service { 
16. 
17.     
18.    private final String TAG = "PhoneListenerService"; 
19.    @Override 
20.    public IBinder onBind(Intent intent) { 
21.        return null; 
22.    } 
23.     
24.    @Override 
25.    public void onCreate() { 
26.        TelephonyManager telephonyManager = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE); 
27.        telephonyManager.listen(new TeleListine(), PhoneStateListener.LISTEN_CALL_STATE); 
28.        Log.i(TAG,"onCreate"); 
29.        super.onCreate(); 
30.    } 
31.     
32.    private class TeleListine extends PhoneStateListener { 
33.         
34.        private String mobile; //来电电话  
35.        private MediaRecorder recorder; //多媒体刻录文件  
36.        private File autoFile; //保存文件  
37.        private boolean recoder; //是否刻录  
38.         
39.        @Override 
40.        public void onCallStateChanged(int state,String incomingNumber) { 
41.            try{ 
42.                switch(state) { 
43.                case TelephonyManager.CALL_STATE_IDLE : 
44.                     
45.                    if(recoder) { 
46.                        recorder.stop(); 
47.                        recorder.release(); 
48.                        recoder = false; 
49.                    } 
50.                    break; 
51.                     
52.                case TelephonyManager.CALL_STATE_OFFHOOK : 
53.                    recorder = new MediaRecorder(); 
54.                    recorder.setAudioSource(MediaRecorder.AudioSource.MIC);                 //这里只是录制自己的声音，如果想录制双方的通话声音，可改用MediaRecorder.AudioSource.VOICE_CALL  
55.                    recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP); 
56.                    recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB); 
57.                    String root_directory = Environment.getExternalStorageDirectory() + "/recorded_calls"; 
58.                    File root_file = new File(root_directory); 
59.                    if(!root_file.exists()) { 
60.                        root_file.mkdir(); 
61.                    } 
62.                    String record_call = root_directory + "/" + mobile + "_" + System.currentTimeMillis() + ".3gp"; 
63.                    File autoFile = new File(record_call); 
64.                    if(!autoFile.exists()) { 
65.                        autoFile.createNewFile(); 
66.                    } 
67.                    //autoFile = new File(getCacheDir(),mobile+ "_" + System.currentTimeMillis() + ".3gp");  
68.                    recorder.setOutputFile(autoFile.getAbsolutePath()); 
69.                    recorder.prepare(); 
70.                    recorder.start(); 
71.                    recoder = true; 
72.                    Log.i(TAG,"接起电话"); 
73.                    break; 
74.                     
75.                case TelephonyManager.CALL_STATE_RINGING : 
76.                    mobile = incomingNumber; 
77.                    Log.i(TAG,"mobile=" + mobile); 
78.                    break; 
79.                default : 
80.                    break; 
81.                } 
82.            }catch(Exception e) { 
83.                Log.i(TAG,e.toString()); 
84.                e.printStackTrace(); 
85.            } 
86.            super.onCallStateChanged(state, incomingNumber); 
87.        } 
88.         
89.         
90.    } 
91. 
92.} 
package com.example.service_record_call;

import java.io.File;

import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.media.MediaRecorder;
import android.os.Environment;
import android.os.IBinder;
import android.telephony.PhoneStateListener;
import android.telephony.TelephonyManager;
import android.util.Log;

public class PhoneListenerService extends Service {

 
 private final String TAG = "PhoneListenerService";
 @Override
 public IBinder onBind(Intent intent) {
  return null;
 }
 
 @Override
 public void onCreate() {
  TelephonyManager telephonyManager = (TelephonyManager)getSystemService(Context.TELEPHONY_SERVICE);
  telephonyManager.listen(new TeleListine(), PhoneStateListener.LISTEN_CALL_STATE);
  Log.i(TAG,"onCreate");
  super.onCreate();
 }
 
 private class TeleListine extends PhoneStateListener {
  
  private String mobile; //来电电话
  private MediaRecorder recorder; //多媒体刻录文件
  private File autoFile; //保存文件
  private boolean recoder; //是否刻录
  
  @Override
  public void onCallStateChanged(int state,String incomingNumber) {
   try{
    switch(state) {
    case TelephonyManager.CALL_STATE_IDLE :
     
     if(recoder) {
      recorder.stop();
      recorder.release();
      recoder = false;
     }
     break;
     
    case TelephonyManager.CALL_STATE_OFFHOOK :
     recorder = new MediaRecorder();
     recorder.setAudioSource(MediaRecorder.AudioSource.MIC);     //这里只是录制自己的声音，如果想录制双方的通话声音，可改用MediaRecorder.AudioSource.VOICE_CALL
     recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
     recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
     String root_directory = Environment.getExternalStorageDirectory() + "/recorded_calls";
     File root_file = new File(root_directory);
     if(!root_file.exists()) {
      root_file.mkdir();
     }
     String record_call = root_directory + "/" + mobile + "_" + System.currentTimeMillis() + ".3gp";
     File autoFile = new File(record_call);
     if(!autoFile.exists()) {
      autoFile.createNewFile();
     }
     //autoFile = new File(getCacheDir(),mobile+ "_" + System.currentTimeMillis() + ".3gp");
     recorder.setOutputFile(autoFile.getAbsolutePath());
     recorder.prepare();
     recorder.start();
     recoder = true;
     Log.i(TAG,"接起电话");
     break;
     
    case TelephonyManager.CALL_STATE_RINGING :
     mobile = incomingNumber;
     Log.i(TAG,"mobile=" + mobile);
     break;
    default :
     break;
    }
   }catch(Exception e) {
    Log.i(TAG,e.toString());
    e.printStackTrace();
   }
   super.onCallStateChanged(state, incomingNumber);
  }
  
  
 }

}

别忘了在AndroidManifest.xml中注册组件Service和Broadcast Receiver

 

 

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01.<receiver android:name=".MyBroadcastReceiver" > 
02.    <intent-filter> 
03.        <action android:name="android.intent.action.BOOT_COMPLETED" /> 
04.        <action android:name="zjut.tsw.receiver" /> 
05.    </intent-filter> 
06.</receiver> 
07. 
08.<service android:name=".PhoneListenerService" > 
09.</service> 
        <receiver android:name=".MyBroadcastReceiver" >
            <intent-filter>
                <action android:name="android.intent.action.BOOT_COMPLETED" />
                <action android:name="zjut.tsw.receiver" />
            </intent-filter>
        </receiver>

        <service android:name=".PhoneListenerService" >
        </service>
这样，当您打开了该软件，或者开机后，该服务会自动启动并运行（你可以在Android机上按Menu键->设置->应用程序->运行的服务 查看该服务的具体状态)

当有人打电话给你或者你打给别人，电话录音会保存在/recorded_calls/...里面。(该程序含有潜在的错误，如果通话时间足够多或足够长(煲电话粥的同志们注意了哦)，可能会导致SD卡内存不足)