Creating an Android Application by using XML Layout
Android provides two types of UI
construction model i.e. programmatic UI layout and XML-based layout. In this
article I am going to explain how to create an Android application in Android
Emulator by using XML layout files.
Expand the Project in the
Package Explorer
Expand
res folder
Layout folder
Select
main.xml.
Heres an XML layout file (main.xml) that is identical in behavior to the
programmatically constructed file:
<?xml
version="1.0"
encoding="utf-8"?>
<TextView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/textview01"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="30px"
android:textStyle="bold"
android:typeface="serif"
android:text="@string/hello"/>
The general structure of an Android XML layout file is a tree of XML elements,
wherein each node is the name of a View class (this example, however, is just
one View element). You can use the name of any class that extends
View
as an element in your XML layouts, including custom View classes you define in
your own code. This structure makes it easy to quickly build up UIs, using a
more simple structure and syntax than you would use in a programmatic layout.
This model is inspired by the web development model, wherein you can separate
the presentation of your application (its UI) from the application logic used to
fetch and fill in data.
In the above example there is only one View Element (TextView) which has eight attributes.
Inside the
res/values/ folder open
strings.xml, modify the strings.xml
as shown below:
<?xml
version="1.0"
encoding="utf-8"?>
<resources>
<string name="hello">Welcome! This is my first Android Application</string>
<string name="app_name">FirstAndroidApp</string>
</resources>
Now open and modify your HelloAndroid class and use the XML layout. Edit the
file as shown below:
package
com.example.firstApp;
import
android.app.Activity;
import
android.os.Bundle;
public
class HelloAndroid
extends Activity {
/** Called when the activity is first created. */
@Override
public
void onCreate(Bundle
savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
}
After creating the above changes
run your application:
Right click on the project (FirstAndroidApp) which is shown in the Package
Explorer
Select Run As
Android Application.
Output as shown below:
After performing the above steps
you can easily create and run an Android application by using XML layout files.
Thanks.