Android bitmap image size in XML

Only API 23 or later

Just use

<item
    android:width="200dp"
    android:height="200dp"
    android:drawable="@drawable/splash_background"
    android:gravity="center" />

instead

<item
    android:left="200dp"
    android:right="200dp">

    <bitmap
        android:src="@drawable/splash_background"
        android:gravity="center" />

</item>

If you want to reduce the width and height so it fits on the screen, and you don't need to set exact dimensions, you can simply set left and right on the parent item. That will essentially add a margin around the image so it takes up less space:

<layer-list xmlns:android="http://schemas.android.com/apk/res/android">

    <item
        android:left="20dp"
        android:right="20dp">

        <bitmap
            android:src="@drawable/Icon"
            android:gravity="center" />

    </item>

</layer-list>

Ideally, though, you should upload different size images for each screen resolution (e.g. hdpi, xxhdpi) and then you won't need to programmatically set the size at all. You can see the full list here.

Although there is no width and height parameters for bitmap, you can set bitmap size using gravity and item width/height.

<item
    android:width="230dp"
    android:height="70dp">
    <bitmap
        android:gravity="fill_horizontal|fill_vertical"
        android:src="@drawable/screen" />
</item>

You can set item width and height and scale bitmap inside of it using gravity.

I know this is old question but maybe someone will find it useful.

WARNING:

As already mentioned in comments, this method ONLY works with API level 23 (Android 6.0) and up.