layout - Android ImageView size not scaling with source image

Question

I have a few ImageViews inside a LinearLayout. I need to scale down the ImageViews so that they maintain their aspect ratios whilst fitting inside the LinearLayout vertically. Horizontally, I just need them to be adjacent to each other.

I've made a simplified test bed for this which nests weighted Layouts so that I have a wide, but not very tall, LinearLayout for the ImageViews -

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent">
    <LinearLayout android:id="@+id/linearLayout1" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="5">
        <LinearLayout android:id="@+id/linearLayout3" android:layout_height="fill_parent" android:layout_width="fill_parent" android:layout_weight="1">
            <ImageView android:id="@+id/imageView1" android:layout_height="wrap_content" android:layout_width="wrap_content" android:src="@drawable/test_image" android:scaleType="fitStart"></ImageView>
            <ImageView android:id="@+id/imageView2" android:layout_height="wrap_content" android:layout_width="wrap_content" android:src="@drawable/test_image" android:scaleType="fitStart"></ImageView>
        </LinearLayout>
        <LinearLayout android:id="@+id/linearLayout4" android:layout_height="fill_parent" android:layout_width="fill_parent" android:layout_weight="1"></LinearLayout>
    </LinearLayout>
    <LinearLayout android:id="@+id/linearLayout2" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1"></LinearLayout>
</LinearLayout>

(In the Eclipse layout editor the images are clipped vertically and not scaled at all - but that's just one of those idiosyncrasies that we learn to love)

When run on hardware the images are scaled to the correct height whilst preserving their aspect ratio. My problem is that they are not next to each other. The height of each ImageView correctly matches the height of the LinearLayout. The width of each ImageView is the width of the unscaled image - the actual scaled down images appearing at the left side of their ImageViews. Because of this, I'm getting a large gap between the images.

Ideally I would like to manage this through XML though, if this is not possible, I understand that using a custom view may be the best solution.

I tried creating an IconView (extends ImageView) class which overrides onMeasure so that I could create image views of the necessary size by scaling the width depending on the height. But the parentWidth and parentHeight being passed into the function were the dimensions of the screen and not of the LinearLayout container.

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  int parentWidth = MeasureSpec.getSize(widthMeasureSpec);
  int parentHeight = MeasureSpec.getSize(heightMeasureSpec);
  // Calculations followed by calls to setMeasuredDimension, setLayoutParams
  super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}

So my questions are -

1) Can I amend the XML in some way to make it do what I need?

2) How do I make my custom class get the height of the LinearLayout so that I can calculate the necessary width for the custom images?

Thanks if you've managed to read this far. Even more thanks if you can point me in the direction of a solution!

Answer 1

What about changing your ImageViews to use android:layout_height="fill_parent"?

Edit - took me a while to find, but looking at the source helped me pinpoint adjustViewBounds. You might want to try adding android:adjustViewBounds="true" to your ImageViews. Surprisingly, this defaults to false.