Android SipDemo项目实现SIP协议

上面是android系统下和SIP相关的类和接口。SipDemo总共有三个文件组成，两个activity和一个广播监听者。通过工程文件夹中的AndroidManifest.xml文件可以发现，SipDemo的启动activity是WalkieTalkieActivity类。

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.walkietalkie);

        ToggleButton pushToTalkButton = (ToggleButton) findViewById(R.id.pushToTalk);
        pushToTalkButton.setOnTouchListener(this);
        // Set up the intent filter.  This will be used to fire an
        // IncomingCallReceiver when someone calls the SIP address used by this
        // application.
        IntentFilter filter = new IntentFilter();
        filter.addAction("android.SipDemo.INCOMING_CALL");
        callReceive