Part 2: Setting up the xml

Hello there continuing from where we left ie, activity_main.xml 

copy the below code in between  the xml file where linear layout has been defined

 

after this xml part is done. (dont worry will come to explaining the code shortly )

Moving on to strings.xml located at   res>values>strings.xml 

 here the name is the variable we used in xml to reference the string defined in value. It is done so that if we need to change the variable we may change the value from here only and the value will be changed from complete application (off course where we have defined the variable)

for example: name app_name is defined with value my first app, this means if we want to change the name of our app all we need to do is change the value here and name will be changed from every where wher variable app_name is used.

to make attributes click on add > select String> enter the values for name& value, and you are done.

 

here we have used values as below

 

EXPLAINING THE CODE

So the section where we understand what everything we just did, comes here :)

<TextView  //defining the text area and the text to be displayed        android:layout_width="fill_parent" //defines the width of text area
        android:layout_height="wrap_content"// defines the height of text area
        android:text="@string/head" // this is where the variable head is defined      which has value in strings.xml
        android:textSize="45sp"  //defines the size of text
        android:layout_gravity="center" // defines the layout alignment
        android:gravity="center" //defines the text alignment
        android:id="@+id/tvDisplay" // defines the id. it will be used later in funcionality
        /> // closing the textview tag

 

After this we defined the two buttons one for add other for subtract, the attributes we used in them too are similar  and differ in id, and text. and ofcourse we used button tag for buttons<Button></Button>

So this was all for today after completing till here we will be having output that may look like this

 for any query or suggestions comment or share .