锁屏流程

PhoneWindowManager.java

systemReady()-->mKeyguardMediator.onSystemReady();

KeyguardViewMediator.java

onSystemReady-->doKeyguardLocked();

doKeyguardLocked-->showLocked-->mHandler.obtainMessage(SHOW, options);-->handleShow-->mKeyguardViewManager.show(options);

-->

KeyguardViewManager.java

show-->

maybeCreateKeyguardLocked(enableScreenRotation, false, options);

mKeyguardHost.setSystemUiVisibility(visFlags);

        mViewManager.updateViewLayout(mKeyguardHost, mWindowLayoutParams);
        mKeyguardHost.setVisibility(View.VISIBLE);
        mKeyguardView.show();

KeyguardHostView.java

show-->showPrimarySecurityScreen-->showSecurityScreen(securityMode);-->getSecurityView

getSecurityView可以把三方锁屏添加到这里来

当按电源键时