`sap.m.HeaderContainer` triggers rendering twice - sapui5

Question

Why are the rendering events of the view (such as onBeforeRendering and onAfterRendering) in the scenario 1 triggered twice?
Scenario 1
Sample.view.xml
<mvc:View xmlns:mvc="sap.ui.core.mvc"
xmlns="sap.m"
controllerName="my.controller.Sample">
<Page id="EmpStat" showHeader="false">
<HeaderContainer>
<!-- ... -->
</HeaderContainer>
</Page>
</mvc:View>
Sample.controller.js
onAfterRendering: function() {
alert("Test"); // called twice
},
Scenario 2
Sample.view.xml
<mvc:View xmlns:mvc="sap.ui.core.mvc"
xmlns:layout="sap.ui.layout"
xmlns="sap.m"
controllerName="my.controller.Sample">
<Page>
<!-- No <HeaderContainer> -->
<layout:Grid>
<!-- ... -->
</layout:Grid>
</Page>
</mvc:View>
Sample.controller.js
onAfterRendering: function() {
alert("Test"); // called once.
},

Answer 1

HeaderContainer has a borrowed class onAfterRendering from sap.ui.core.control, hence in scenario one headerContainer calls this method once and sap.m.Page calls the method another time.
The only way is it to handle the scenario is bypassing the execution of your code a second time either by using event parent source check or by using the logic I have given below as in most of the cases the event gets called only twice.
You can create a counter in onInit() and then update the value in onAfterRendering() and execute the corresponding code only when the condition is matched with the counter value.
onInit:function(){
this.afterRenderingCount = 0;
},
onAfterRendering: function (oEvent) {
if(this.afterRenderingCount === 1){
this.afterRenderingCount =0;
//method call
this.exampleMethod();
}
this.afterRenderingCount++;
}