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/*
* Copyright (C) 2013 Jorge Ruesga
*
* 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 com.ruesga.android.wallpapers.photophase.widgets;
import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.widget.ScrollView;
/**
* A scroll view that notifies the end of the scroll to create new views
* dynamically.
*/
public class VerticalEndlessScroller extends ScrollView {
/**
* Interface to communicate end-scroll events
*/
public interface OnEndScrollListener {
/**
* Called when the scroll reachs the end of the scroll
*/
void onEndScroll();
}
private OnEndScrollListener mCallback;
private int mEndPadding = 0;
private boolean mSwitch = false;
/**
* Constructor of <code>VerticalEndlessScroller</code>.
*
* @param context The current context
*/
public VerticalEndlessScroller(Context context) {
super(context);
}
/**
* Constructor of <code>VerticalEndlessScroller</code>.
*
* @param context The current context
* @param attrs The attributes of the XML tag that is inflating the view.
*/
public VerticalEndlessScroller(Context context, AttributeSet attrs) {
super(context, attrs);
}
/**
* Constructor of <code>VerticalEndlessScroller</code>.
*
* @param context The current context
* @param attrs The attributes of the XML tag that is inflating the view.
* @param defStyle The default style to apply to this view. If 0, no style
* will be applied (beyond what is included in the theme). This may
* either be an attribute resource, whose value will be retrieved
* from the current theme, or an explicit style resource.
*/
public VerticalEndlessScroller(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
/**
* Method that set the callback for notify end-scroll events
*
* @param callback The callback
*/
public void setCallback(OnEndScrollListener callback) {
mCallback = callback;
}
/**
* Method that set the end padding for fired the event
*
* @param endPadding The end padding
*/
public void setEndPadding(int endPadding) {
this.mEndPadding = endPadding;
}
/**
* {@inheritDoc}
*/
@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
// We take the last child in the scrollview
View view = getChildAt(getChildCount() - 1);
int diff = (view.getBottom() - (getHeight() + getScrollY()));
if ((!mSwitch && diff <= mEndPadding)) {
if (mCallback != null) {
mCallback.onEndScroll();
mSwitch = true;
return;
}
} else if (diff > mEndPadding) {
mSwitch = false;
}
}
}
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