Double tap to zoom on ImageView

[Adam Schweitzer]

I am trying to implement zoom functionality on an ImageView, similar to the built-in Photos app on iOS (I don't have a physical android device to make a more suitable analogy). Pinch-to-zoom would be nice to have, but zoom on double-tap is essential.

I've tried some sample code (ex. http://android-journey.blogspot.com/2010/01/android-gestures.html), but this does not work for me, for some reason; none of the event handlers fire (I may be omitting something simple?).

Can someone point me in the right direction?

For troubleshooting purposes, I used sample code unmodified from the above link, on an Android 2.3 emulator in an application with android:minSdkVersion=7 and the following layout:

    <?xml version="1.0" encoding="utf-8"?>
    <ImageView  
    xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="fill_parent" 
        android:layout_height="fill_parent" 
        android:src="@drawable/android"
        android:id="@+id/image"
        />