Android LinearLayout with Examples

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  Keywords : Android linear layout to arrange all child elements in single direction either vertical or horizontal, Android specify linear layout orientation using android:orientation attribute

Here we will learn android linearlayout with examples and how to use android linearlayout to align all child elements in one direction, either horizontally or vertically with examples.

Android Linear Layout

In android, LinearLayout is a ViewGroup subclass which is used to render all child View instances one by one either in Horizontal direction or Vertical direction based on the orientation property.

 

In android, we can specify the linear layout orientation using android:orientation attribute.

 

Following is the pictorial representation of linear layout in android applications.

 

ANdroid LinearLayout Example Diagram

In LinearLayout, the child View instances arranged one by one, so the horizontal list will have only one row of multiple columns and vertical list will have one column of multiple rows.

Android LinearLayout Declaration

Following is the way we need to define the LinearLayout in android applications.

 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   
android:layout_width="match_parent"
   
android:layout_height="match_parent"
   
android:orientation="vertical" >
   
<!-- Add Child Views Here -->

</LinearLayout>

If you observe above code snippet, here we defined orientation as vertical, so this aligns all its child layout / views vertically.

Android LinearLayout Example

Following is the example of creating a LinearLayout with different controls in android application.

 

Create a new android application using android studio and give names as LinearLayout. In case if you are not aware of creating an app in android studio check this article Android Hello World App.

 

Now open an activity_main.xml file from \res\layout path and write the code like as shown below

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
   
android:layout_width="match_parent"
   
android:layout_height="match_parent"
   
android:paddingLeft="20dp"
   
android:paddingRight="20dp"
   
android:orientation="vertical" >
    <
EditText
       
android:id="@+id/txtTo"
       
android:layout_width="match_parent"
       
android:layout_height="wrap_content"
       
android:hint="To"/>
    <
EditText
       
android:id="@+id/txtSub"
       
android:layout_width="match_parent"
       
android:layout_height="wrap_content"
       
android:hint="Subject"/>
    <
EditText
       
android:id="@+id/txtMsg"
       
android:layout_width="match_parent"
       
android:layout_height="0dp"
       
android:layout_weight="1"
       
android:gravity="top"
       
android:hint="Message"/>
    <
Button
       
android:layout_width="100dp"
        
android:layout_height="wrap_content"
       
android:layout_gravity="right"
       
android:text="Send"/>
</
LinearLayout>

Once we are done with creation of layout, we need to load the XML layout resource from our activity onCreate() callback method, for that open main activity file MainActivity.java from \java\com.tutlane.linearlayout path and write the code like as shown below.

MainActivity.java

package com.tutlane.linearlayout;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {
   
@Override
   
protected void onCreate(Bundle savedInstanceState) {
       
super.onCreate(savedInstanceState);
        setContentView(R.layout.
activity_main);
    }
}

If you observe above code we are calling our layout using setContentView method in the form of R.layout.layout_file_name. Here our xml file name is activity_main.xml so we used file name activity_main.

 

Generally, during the launch of our activity, onCreate() callback method will be called by android framework to get the required layout for an activity.

Output of Android LinearLayout Example

When we run above example using android virtual device (AVD) we will get a result like as shown below.

 

Android LinearLayout Example Result

Layout Weight Attribute

If you observe above example we used layout weight attribute (android:layout_weight) in child view. Actually, this attribute is used by child views to specify how much space the View should occupy on the screen. If we assign larger weight value to child view, then it will expand to fill any remaining space in the parent view.

 

If you observe above example, we used three text fields and we assigned weight value to only one text field. The two text fields without weight will occupy only the area required for its content and the other text field with weight value will expand to fill the remaining space after all three fields measured.

 

This is how we can use LinearLayout in android applications to render all View instances one by one either in Horizontal direction or Vertical direction based on the orientation property.

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