<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:orientation="vertical" android:layout_width="match_parent"android:layout_height="match_parent"><Buttonandroid:id="@+id/start"android:layout_width="wrap_content"android:layout_height="wrap_content"android:textSize="18sp"android:text="开始录音"android:onClick="click"/>
</LinearLayout>

package xidian.dy.com.chujia;import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Toast;public class MainActivity extends AppCompatActivity {Intent service;@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);}public void click(View v){Toast.makeText(this,"开启服务",Toast.LENGTH_SHORT).show();service = new Intent(this, MyService.class);startService(service);}}

package xidian.dy.com.chujia;import android.app.Service;
import android.content.Intent;
import android.media.MediaRecorder;
import android.os.Environment;
import android.os.IBinder;
import android.support.annotation.Nullable;
import android.telephony.PhoneStateListener;
import android.telephony.TelephonyManager;
import android.util.Log;import java.io.IOException;/*** Created by dy on 2016/7/12.*/
public class MyService extends Service {TelephonyManager tm;@Overridepublic void onCreate() {super.onCreate();//获取电话管理器tm = (TelephonyManager) getSystemService(TELEPHONY_SERVICE);//对感兴趣的事件进行监听,传入回调函数tm.listen(new MyListener(),PhoneStateListener.LISTEN_CALL_STATE);}class MyListener extends PhoneStateListener{MediaRecorder mRecorder;//一旦电话状态改变该方法被调用
        @Overridepublic void onCallStateChanged(int state, String incomingNumber) {super.onCallStateChanged(state, incomingNumber);switch (state){//电话处于空闲状态停止录音case TelephonyManager.CALL_STATE_IDLE:if(mRecorder != null){mRecorder.stop();mRecorder.release();mRecorder = null;}break;//电话处于响铃状态case TelephonyManager.CALL_STATE_RINGING:mRecorder = new MediaRecorder();mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);mRecorder.setOutputFile(Environment.getExternalStorageDirectory().toString() + "/record.3gp");mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);try {mRecorder.prepare();} catch (IOException e) {Log.e(this.getClass().getName(), "prepare() failed");}break;//电话处于摘机状态case TelephonyManager.CALL_STATE_OFFHOOK:if(mRecorder != null){mRecorder.start();}break;}}}@Nullable@Overridepublic IBinder onBind(Intent intent) {return null;}
}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="xidian.dy.com.chujia"><uses-permission android:name="android.permission.READ_PHONE_STATE"/><uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /><uses-permission android:name="android.permission.RECORD_AUDIO" /><applicationandroid:allowBackup="true"android:icon="@mipmap/ic_launcher"android:label="@string/app_name"android:supportsRtl="true"android:theme="@style/AppTheme"><activityandroid:name=".MainActivity"android:label="主界面"><intent-filter><action android:name="android.intent.action.MAIN" /><category android:name="android.intent.category.LAUNCHER" /></intent-filter></activity><service android:name=".MyService" />
</application>
</manifest>