1:AndroidManifest.xml 注册广播

<!--打电话广播-->
<uses-permission android:name="android.permission.PROCESS_OUTGOING_CALLS"/>
<!--监听电话状态-->
<uses-permission android:name="android.permission.READ_PHONE_STATE"/>

<receiver android:name=".service.PhoneBroadcastReceiver">
    <intent-filter android:priority="1000">
        //主动打电话时,发送的广播
        <action android:name="android.intent.action.NEW_OUTGOING_CALL"/>
        //电话状态改变时,发送的广播 (振铃,挂断,接通)
        <action android:name="android.intent.action.PHONE_STATE"/>
    </intent-filter>
</receiver>

2:onReceive

@Override
public void onReceive(Context context, Intent intent) {
    log.info("收到电话广播:{}", intent == null ? "null" : intent.getAction());

    // 如果是拨打电话
    if (intent.getAction().equals(Intent.ACTION_NEW_OUTGOING_CALL)) {
        //拨打电话会优先,收到此广播. 再收到 android.intent.action.PHONE_STATE 的 TelephonyManager.CALL_STATE_OFFHOOK 状态广播;

        String phoneNumber = intent.getStringExtra(Intent.EXTRA_PHONE_NUMBER);
        log.info("call OUT:{}", phoneNumber);//获取拨打的手机号码
    } else {
        // 如果是来电
        TelephonyManager tManager = (TelephonyManager) context
                .getSystemService(Service.TELEPHONY_SERVICE);
        //电话的状态
        switch (tManager.getCallState()) {
            case TelephonyManager.CALL_STATE_RINGING:
                //等待接听状态
                mIncomingNumber = intent.getStringExtra("incoming_number");
                log.info("RINGING :" + mIncomingNumber);
                break;
            case TelephonyManager.CALL_STATE_OFFHOOK:
                //接听状态
                break;
            case TelephonyManager.CALL_STATE_IDLE:
                //挂断状态
                break;
        }
    }
}

3:附加阅读
如果需要挂断电话参考: (可以模拟耳机线上的接听和挂断广播, 实现相应的功能.)
http://gqdy365.iteye.com/blog/2173057
http://bbs.51cto.com/thread-1078059-1.html
http://blog.csdn.net/sodino/article/details/6181610