title: onTouch exception when scrolling multiple WebViews
body: <p>I have an app that uses multiple <code>WebView</code>s next to each other to display content. When vertically scrolling on one, and I scroll another before the first stops completely I get an exception with the below stack trace. The first line in the stack is the most puzzling to me. I do not know what a <code>VelocityTracker</code> is, or what any of the other variables refer to.</p>
  
  <pre><code>11-30 10:47:04.740: E/webview(2199): Got null mVelocityTracker when mPreventDefault = 0 mDeferTouchProcess = false mTouchMode = 3
  11-30 10:50:23.771: D/AndroidRuntime(2199): Shutting down VM
  11-30 10:50:23.771: W/dalvikvm(2199): threadid=1: thread exiting with uncaught exception (group=0x40015560)
  11-30 10:50:23.795: E/AndroidRuntime(2199): FATAL EXCEPTION: main
  11-30 10:50:23.795: E/AndroidRuntime(2199): java.lang.NullPointerException
  11-30 10:50:23.795: E/AndroidRuntime(2199):     at android.webkit.WebView.onTouchEvent(WebView.java:5283)
  11-30 10:50:23.795: E/AndroidRuntime(2199):     at android.view.View.dispatchTouchEvent(View.java:3885)
  11-30 10:50:23.795: E/AndroidRuntime(2199):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:903)
  11-30 10:50:23.795: E/AndroidRuntime(2199):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:942)
  11-30 10:50:23.795: E/AndroidRuntime(2199):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:942)
  11-30 10:50:23.795: E/AndroidRuntime(2199):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:942)
  11-30 10:50:23.795: E/AndroidRuntime(2199):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:942)
  11-30 10:50:23.795: E/AndroidRuntime(2199):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:942)
  11-30 10:50:23.795: E/AndroidRuntime(2199):     at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:942)
  11-30 10:50:23.795: E/AndroidRuntime(2199):     at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1702)
  11-30 10:50:23.795: E/AndroidRuntime(2199):     at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1125)
  11-30 10:50:23.795: E/AndroidRuntime(2199):     at android.app.Activity.dispatchTouchEvent(Activity.java:2132)
  11-30 10:50:23.795: E/AndroidRuntime(2199):     at
  ...
  </code></pre>
  
  <p>I am using a sub-classed <code>WebView</code>, but I do not override the <code>onTouchEvent()</code> method. </p>
  
  <p>Interestingly I am only finding this error on the OS v2.3 device I am using as well as any OS v2.x emulator. Anytime I test on a 4.x device everything is fine and all WebViews are able to handle touching and scrolling simultaneously.</p>
  
  <p>What is going on? Is this a known bug in Android? I could not find any record of a similar circumstance. Any suggestions for a workaround? I could just prevent other <code>WebView</code>s from being touched so long as one of them is scrolling, but that seems ridiculous.</p>