Android Imageview Maintain Aspect Ratio

The following will match parent's width and adjust height to maintain aspect ratio.

<ImageView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:src="@drawable/placeholder_150"
    android:adjustViewBounds="true"
    android:scaleType="centerCrop"
    />

NOTE: @drawable/placeholder_150 is a square image.

NOTE: You might want to experiment with scaleType fitCenter or fitXY as well.

References:

• https://stackoverflow.com/questions/2521959/how-to-scale-an-image-in-imageview-to-keep-the-aspect-ratio