Equal_width.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main2"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.shohruh.gridlayout.Main2Activity">

    <GridLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:columnCount="3"
        >


        <Button
            android:layout_width="0dp"
            android:layout_height="100dp"
            android:layout_columnWeight="1"

            />

        <Button
            android:layout_width="0dp"
            android:layout_height="100dp"
            android:layout_columnWeight="1"
            android:layout_marginLeft="10dp"
            android:layout_marginRight="10dp"
            />

        <Button
            android:layout_width="0dp"
            android:layout_height="100dp"
            android:layout_columnWeight="1"

            />



        <Button
            android:layout_width="0dp"
            android:layout_height="100dp"
            android:layout_columnWeight="1"

            />
        <Button
            android:layout_width="0dp"
            android:layout_height="100dp"
            android:layout_columnWeight="1"
            android:layout_marginLeft="10dp"
            android:layout_marginRight="10dp"
            />

        <Button
            android:layout_width="0dp"
            android:layout_height="100dp"
            android:layout_columnWeight="1"

            />



    </GridLayout>







</RelativeLayout>