Android bitmap image size in XML

Question

In my XML file, I\'m using bitmap as the following

Here t

Answer 1

From Android Developers I saw that there is no tag for Bitmap XML that allow you to change it size. You need to do this via some Graphic Applications like GIMP. As @Kevin Cooper told already, ideally you need to create different sets of resources (with different sizes) for different screen types.

But still you can resize it using width and height attributes in ImageView, instead of creating bitmap with different size:

<ImageView
    android:layout_width="50dp"
    android:layout_height="50dp"
    android:scaleType="center"
    android:src="@drawable/Icon" />

If you want to reuse this image in other places, you can create separate style and reuse it:

// in styles.xml
<style name="Icon24x24">
    <item name="android:src">@drawable/Icon</item>
    <item name="android:gravity">center</item>
    <item name="android:layout_width">24dp</item>
    <item name="android:layout_height">24dp</item>
</style>

// in layout.xml
<ImageView style="@style/Icon24x24"/>

Another way of reusing, may be creating of separate layout file for one ImageView and then including in to other layouts.

If you want to use this bitmap inside of layer list, please see @Kevin Cooper answer, as he suggested it is possible to add paddings to layer list item:

<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>

And as @Nicolo also pointed, form API 23, it is possible to set android:width and android:height" to item.

Answer 2

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.