ImageView Zoom and Scroll

I modify the ImageViewTouch.java code for android 2.1 and success work it.

package it.sephiroth.android.library.imagezoom;

import android.content.Context;
import android.graphics.PointF;
import android.util.AttributeSet;
import android.util.FloatMath;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.ViewConfiguration;

public class ImageViewTouch extends ImageViewTouchBase{

protected static final float MIN_DIST = 10F;

static final float MIN_ZOOM = 0.9f;
protected GestureDetector mGestureDetector;
protected int mTouchSlop;
protected float mCurrentScaleFactor;
protected float mScaleFactor;
protected int mDoubleTapDirection;
protected GestureListener mGestureListener;

PointF start = new PointF();
PointF mid = new PointF();
float oldDist;

private final static int NONE = 0;
private final static int DRAG = 1;
private final static int ZOOM = 2;

private int touchState = NONE;

public ImageViewTouch( Context context, AttributeSet attrs )
{
super( context, attrs );
}

@Override
protected void init()
{
super.init();
mTouchSlop = ViewConfiguration.getTouchSlop();
mGestureListener = new GestureListener();

mGestureDetector = new GestureDetector(getContext(), mGestureListener);
mCurrentScaleFactor = 1f;
mDoubleTapDirection = 1;
}

@Override
public void setImageRotateBitmapReset( RotateBitmap bitmap, boolean reset )
{
super.setImageRotateBitmapReset( bitmap, reset );
mScaleFactor = getMaxZoom() / 3;
}

@Override
public boolean onTouchEvent( MotionEvent event )
{
if (touchState != ZOOM) mGestureDetector.onTouchEvent( event );
int action = event.getAction();
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
start.set(event.getX(), event.getY());
touchState = DRAG;
break;
case MotionEvent.ACTION_UP:
touchState = NONE;
if ( getScale() MIN_DIST) {
touchState = ZOOM;
midPoint(mid, event);
}
break;
case MotionEvent.ACTION_MOVE:
if (touchState == ZOOM) {
onScale (event);
}
break;
}
return true;
}

// calculate the distance
private float spacing(MotionEvent event) {
float x = event.getX(0) – event.getX(1);
float y = event.getY(0) – event.getY(1);
return FloatMath.sqrt(x * x + y * y);
}

// calculate the center point
private void midPoint(PointF point, MotionEvent event) {
float x = event.getX(0) + event.getX(1);
float y = event.getY(0) + event.getY(1);
point.set(x / 2, y / 2);
}

public boolean onScale( MotionEvent event )
{
float span = spacing(event);
float targetScale = span / oldDist;
if (span > MIN_DIST) {
targetScale = Math.min( getMaxZoom(), Math.max( targetScale, MIN_ZOOM ) );
zoomTo( targetScale, mid.x, mid.y);
mCurrentScaleFactor = Math.min( getMaxZoom(), Math.max( targetScale, MIN_ZOOM ) );
mDoubleTapDirection = 1;
invalidate();
return true;
}
return false;
}

@Override
protected void onZoom( float scale )
{
super.onZoom( scale );
mCurrentScaleFactor = scale;
}

protected float onDoubleTapPost( float scale, float maxZoom )
{
if ( mDoubleTapDirection == 1 ) {
if ( ( scale + ( mScaleFactor * 2 ) ) 800 || Math.abs( velocityY ) > 800 ) {
scrollBy( diffX / 2, diffY / 2, 300 );
invalidate();
}
return super.onFling( e1, e2, velocityX, velocityY );
}
}
}

I have the same problem as bruno with android 3.x. Image displays fine, but as soon as I double touch it, the image disappears?