/*******************************************************************************
 * Copyright 2011, 2012 Chris Banes.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *******************************************************************************/
package uk.co.senab.photoview.gestures;

import android.annotation.TargetApi;
import android.content.Context;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;

@TargetApi(8)
public class FroyoGestureDetector extends EclairGestureDetector {

    protected final ScaleGestureDetector mDetector;

    public FroyoGestureDetector(Context context) {
        super(context);
        ScaleGestureDetector.OnScaleGestureListener mScaleListener = new ScaleGestureDetector.OnScaleGestureListener() {

            @Override
            public boolean onScale(ScaleGestureDetector detector) {
                float scaleFactor = detector.getScaleFactor();

                if (Float.isNaN(scaleFactor) || Float.isInfinite(scaleFactor))
                    return false;

                mListener.onScale(scaleFactor,
                        detector.getFocusX(), detector.getFocusY());
                return true;
            }

            @Override
            public boolean onScaleBegin(ScaleGestureDetector detector) {
                return true;
            }

            @Override
            public void onScaleEnd(ScaleGestureDetector detector) {
                // NO-OP
            }
        };
        mDetector = new ScaleGestureDetector(context, mScaleListener);
    }

    @Override
    public boolean isScaling() {
        return mDetector.isInProgress();
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        mDetector.onTouchEvent(ev);
        return super.onTouchEvent(ev);
    }

}

/*******************************************************************************
 * Copyright 2011, 2012 Chris Banes.
 * <p/>
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * <p/>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p/>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *******************************************************************************/
package uk.co.senab.photoview.gestures;

import android.annotation.TargetApi;
import android.content.Context;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;

@TargetApi(8)
public class FroyoGestureDetector extends EclairGestureDetector {

    protected final ScaleGestureDetector mDetector;

    public FroyoGestureDetector(Context context) {
        super(context);
        ScaleGestureDetector.OnScaleGestureListener mScaleListener = new ScaleGestureDetector.OnScaleGestureListener() {

            @Override
            public boolean onScale(ScaleGestureDetector detector) {
                float scaleFactor = detector.getScaleFactor();

                if (Float.isNaN(scaleFactor) || Float.isInfinite(scaleFactor))
                    return false;

                mListener.onScale(scaleFactor,
                        detector.getFocusX(), detector.getFocusY());
                return true;
            }

            @Override
            public boolean onScaleBegin(ScaleGestureDetector detector) {
                return true;
            }

            @Override
            public void onScaleEnd(ScaleGestureDetector detector) {
                // NO-OP
            }
        };
        mDetector = new ScaleGestureDetector(context, mScaleListener);
    }

    @Override
    public boolean isScaling() {
        return mDetector.isInProgress();
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        try {
            mDetector.onTouchEvent(ev);
            return super.onTouchEvent(ev);
        } catch (IllegalArgumentException e) {
            // Fix for support lib bug, happening when onDestroy is
            return true;
        }
    }
}

Update FroyoGestureDetector