android入門scrollviewを利用して動的スクロールを実現する

2014年8月23日

1.androidコード：
package com.startnews24;

public interface ScrollViewListener { 　//interfaceを定義

void onScrollChanged(ObservableScrollView scrollView, int x, int y, int oldx, int oldy);

}

package com.startnews24;

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

public class ObservableScrollView extends ScrollView {

private ScrollViewListener scrollViewListener = null;

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

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

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

public void setScrollViewListener(ScrollViewListener scrollViewListener) {
this.scrollViewListener = scrollViewListener;
}

@Override
protected void onScrollChanged(int x, int y, int oldx, int oldy) {
super.onScrollChanged(x, y, oldx, oldy);
if(scrollViewListener != null) {
scrollViewListener.onScrollChanged(this, x, y, oldx, oldy);
}
}

｝

2.説明
Unfortunately Google never thought that we would need to access it, which is why they made it protected and didn’t add a “setOnScrollChangedListener" hook. So we will have to do that for ourselves.