Please use layout_column and layout_row to specify in which row and in which column of that row you want to place your ImageView.
<?xml version="1.0" encoding="UTF-8"?>
<GridLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:columnCount="4"
android:rowCount="4"
tools:context=".MainActivity" >
<ImageView
android:layout_column="1"
android:layout_row="0"
android:src="@drawable/pic1" />
<ImageView
android:layout_column="2"
android:layout_row="0"
android:src="@drawable/pic2" />
</GridLayout>
Also reading the doc I found that we can have control over the stretch using Gravity. It says,
Excess Space Distribution:
GridLayout's distribution of excess space is based on priority rather than weight. A child's ability to stretch is inferred from the alignment properties of its row and column groups (which are typically set by setting the gravity property of the child's layout parameters). If alignment was defined along a given axis then the component is taken as flexible in that direction. If no alignment was set, the component is instead assumed to be inflexible.
Multiple components in the same row or column group are considered to act in parallel. Such a group is flexible only if all of the components within it are flexible. Row and column groups that sit either side of a common boundary are instead considered to act in series. The composite group made of these two elements is flexible if one of its elements is flexible.
To make a column stretch, make sure all of the components inside it define a gravity. To prevent a column from stretching, ensure that one of the components in the column does not define a gravity.
AND
To place equal amounts of space around a component in a cell group; use CENTER alignment (or gravity). For complete control over excess space distribution in a row or column; use a LinearLayout subview to hold the components in the associated cell group. When using either of these techniques, bear in mind that cell groups may be defined to overlap.
