ObservableScrollView.java

package com.smartandroid.sa.fading;

import android.content.Context;
import android.os.Build;
import android.util.AttributeSet;
import android.widget.ScrollView;

/**
 * @author Cyril Mottier with modifications from Manuel Peinado
 */
public class ObservableScrollView extends ScrollView implements
		ObservableScrollable {
	// Edge-effects don't mix well with the translucent action bar in Android
	// 2.X
	private boolean mDisableEdgeEffects = true;

	private OnScrollChangedCallback mOnScrollChangedListener;

	public ObservableScrollView(Context context) {
		super(context);
	}

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

	public ObservableScrollView(Context context, AttributeSet attrs,
			int defStyle) {
		super(context, attrs, defStyle);
	}

	@Override
	protected void onScrollChanged(int l, int t, int oldl, int oldt) {
		super.onScrollChanged(l, t, oldl, oldt);
		if (mOnScrollChangedListener != null) {
			mOnScrollChangedListener.onScroll(l, t);
		}
	}

	@Override
	protected float getTopFadingEdgeStrength() {
		// http://stackoverflow.com/a/6894270/244576
		if (mDisableEdgeEffects
				&& Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB) {
			return 0.0f;
		}
		return super.getTopFadingEdgeStrength();
	}

	@Override
	protected float getBottomFadingEdgeStrength() {
		// http://stackoverflow.com/a/6894270/244576
		if (mDisableEdgeEffects
				&& Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB) {
			return 0.0f;
		}
		return super.getBottomFadingEdgeStrength();
	}

	@Override
	public void setOnScrollChangedCallback(OnScrollChangedCallback callback) {
		mOnScrollChangedListener = callback;
	}
}