Switch to HackyViewPager for media preview

Fixes #7344
Fixes #7335

res/layout/media_preview_activity.xml

@@ -5,7 +5,7 @@
                 android:layout_height="match_parent"
                 android:background="@color/gray95">
 
-    <android.support.v4.view.ViewPager
+    <org.thoughtcrime.securesms.components.viewpager.HackyViewPager
             android:id="@+id/media_pager"
             android:layout_width="match_parent"
             android:layout_height="match_parent"/>

src/org/thoughtcrime/securesms/components/viewpager/HackyViewPager.java

@@ -0,0 +1,43 @@
+package org.thoughtcrime.securesms.components.viewpager;
+
+
+import android.content.Context;
+import android.support.v4.view.ViewPager;
+import android.util.AttributeSet;
+import android.util.Log;
+import android.view.MotionEvent;
+
+/**
+ * Hacky fix for http://code.google.com/p/android/issues/detail?id=18990
+ * <p/>
+ * ScaleGestureDetector seems to mess up the touch events, which means that
+ * ViewGroups which make use of onInterceptTouchEvent throw a lot of
+ * IllegalArgumentException: pointerIndex out of range.
+ * <p/>
+ * There's not much I can do in my code for now, but we can mask the result by
+ * just catching the problem and ignoring it.
+ *
+ * @author Chris Banes
+ */
+public class HackyViewPager extends ViewPager {
+
+  private static final String TAG = HackyViewPager.class.getSimpleName();
+
+  public HackyViewPager(Context context) {
+    super(context);
+  }
+
+  public HackyViewPager(Context context, AttributeSet attrs) {
+    super(context, attrs);
+  }
+
+  @Override
+  public boolean onInterceptTouchEvent(MotionEvent ev) {
+    try {
+      return super.onInterceptTouchEvent(ev);
+    } catch (IllegalArgumentException e) {
+      Log.w(TAG, e);
+      return false;
+    }
+  }
+}