imagebutton - How do I keep the aspect ratio on image buttons in android?

Question

I have 5 square ImageButtons that I want to have lined up side by side on the bottom of the screen. I have each one set (different id's) as:

        <ImageButton
         android:id="@+id/box1" 
         android:layout_width="fill_parent"
         android:layout_height="wrap_content" 
         android:layout_gravity="center"
         android:adjustViewBounds="true"
         android:scaleType="fitXY"
         android:layout_weight="1"
         android:layout_margin="1dp"
         /> 

and I have the background assigned in main java like this:

    int[] imageIds = new int[] {R.id.box1,R.id.box2,R.id.box3,R.id.box4,R.id.box5};
    for(int i = 0; i<5; i++){
        imageButtons[i] = (ImageButton) findViewById(imageIds[i]);
        imageButtons[i].setBackgroundResource(R.drawable.blank);
    }

What I would like to have it do is scale the width to fit neatly side-by-side at the bottom of the screen (which it does now ok), but have the height automatically scale to match the width as well. is this possible? I don't want to use setImageSource because then it puts a border around the imagebutton.

Answer 1

I have had a similar headache in trying to get my buttons in a row. The solution I found was to use ImageButton and the android:src property (setImageSource in code) in combination with android:background="@null"

As I understand it the background of an image button doesn't get affected by the adjustViewBounds, it is only the imageView which you set in android:src.

The default behavior is then to give you a square button with the imageView in the middle of it. You can override that by setting the background to @null, which leaves you with only the image.

You can then use either a LinearLayout or a table to layout your buttons. I did everything in XML and used the following layout to create a row of two buttons at the bottom of the screen that scale up or down maintaining the aspect ratio with different device screens sizes. Hope this helps.

<TableLayout    
    android:id="@+id/tableLayout2"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_marginBottom="20dip"
    android:stretchColumns="*">

    <TableRow>

     <ImageButton
        android:id="@+id/button_one"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_gravity="center"
        android:layout_weight="0.5"
        android:adjustViewBounds="true"
        android:scaleType="fitCenter"  
        android:onClick="clickOne"
        android:background="@null"
        android:src="@drawable/button_one_drawable" />

    <ImageButton
        android:id="@+id/button_two"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_gravity="center"
        android:layout_weight="0.5"
        android:adjustViewBounds="true"
        android:scaleType="centerInside"  
        android:onClick="clickTwo"
        android:background="@null"
        android:src="@drawable/button_two_drawable" />

    </TableRow>      
</TableLayout>