沉浸式大招

  使用沉浸式时候只要在activity中重写方法  只有在Android 4.4及以上系统才支持沉浸式模式 所以在此加了判断

@Overridepublic void onWindowFocusChanged(boolean hasFocus) {    super.onWindowFocusChanged(hasFocus);    if (hasFocus && Build.VERSION.SDK_INT >= 19) {        View decorView = getWindow().getDecorView();        decorView.setSystemUiVisibility(                View.SYSTEM_UI_FLAG_LAYOUT_STABLE                        | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION                        | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN                        | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION                        | View.SYSTEM_UI_FLAG_FULLSCREEN                        | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);    }}