采用服务实现电话监听

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="visizen.com.service">

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

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <service android:name=".PhoneStatusService"></service>
    </application>

</manifest>

MainActivity

package visizen.com.service;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Intent intent=new Intent(this,PhoneStatusService.class);
        startService(intent);
    }
}

PhoneStatusService

package visizen.com.service;

import android.app.Service;
import android.content.Intent;
import android.media.AudioManager;
import android.media.MediaRecorder;
import android.os.IBinder;
import android.support.annotation.Nullable;
import android.telephony.PhoneStateListener;
import android.telephony.ServiceState;
import android.telephony.TelephonyManager;

import java.io.IOException;

/**
 * 长期在后台运行的组件,如果用户不手动的关闭 , 不会停止的.
 */
public class PhoneStatusService extends Service {
    @Override
    public void onCreate() {
        super.onCreate();
        System.out.println("onCreate");

        TelephonyManager tm = (TelephonyManager) this.getSystemService(this.TELEPHONY_SERVICE);

        tm.listen(new MyPhoneStateListener(), PhoneStateListener.LISTEN_CALL_STATE);

    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        System.out.println("onDestroy");
    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    private class MyPhoneStateListener extends PhoneStateListener {

        private MediaRecorder recorder;

        @Override
        public void onCallStateChanged(int state, String incomingNumber) {

            super.onCallStateChanged(state, incomingNumber);
            switch (state) {
                case TelephonyManager.CALL_STATE_IDLE:
                    System.out.println("空闲状态 ,没有通话 没有响铃");
                    if (recorder != null) {
                        recorder.stop();
                        recorder.reset();   // You can reuse the object by going back to setAudioSource() step
                        recorder.release(); // Now the object cannot be reused
                    }
                    break;
                case TelephonyManager.CALL_STATE_RINGING:
                    System.out.println("发现来电号码 :" + incomingNumber);
                    recorder = new MediaRecorder();
                    recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
                    recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
                    recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
                    recorder.setOutputFile("/sdcard/" + System.currentTimeMillis() + ".3gp");
                    try {
                        recorder.prepare();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }

                    break;
                case TelephonyManager.CALL_STATE_OFFHOOK:
                    System.out.println("通话状态");
                    if (recorder != null) {
                        recorder.start();   // Recording is now started
                    }
                    break;
            }
        }
    }
}