CustomScrollView.java
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package com.hh.xuetubao.Utils;
import android.content.Context;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.widget.ScrollView;
public class CustomScrollView extends ScrollView {
//回调监听接口
private OnScrollChangeListener mOnScrollChangeListener;
//标识是否滑动到顶部
private boolean isScrollToStart = false;
//标识是否滑动到底部
private boolean isScrollToEnd = false;
private static final int CODE_TO_START = 0x001;
private static final int CODE_TO_END = 0x002;
private Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
switch (msg.what) {
case CODE_TO_START:
//重置标志“滑动到顶部”时的标志位
isScrollToStart = false;
break;
case CODE_TO_END:
//重置标志“滑动到底部”时的标志位
isScrollToEnd = false;
break;
default:
break;
}
}
};
public CustomScrollView(Context context) {
super(context);
}
public CustomScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public CustomScrollView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
super.onScrollChanged(l, t, oldl, oldt);
if (mOnScrollChangeListener != null) {
Log.i("CustomScrollView", "scrollY:" + getScrollY());
//滚动到顶部，ScrollView存在回弹效果效应（这里只会调用两次，如果用<=0,会多次触发）
if (getScrollY() == 0) {
//过滤操作，优化为一次调用
if (!isScrollToStart) {
isScrollToStart = true;
mHandler.sendEmptyMessageDelayed(CODE_TO_START, 200);
Log.e("CustomScrollView", "toStart");
mOnScrollChangeListener.onScrollToStart();
}
} else {
View contentView = getChildAt(0);
if (contentView != null && contentView.getMeasuredHeight() == (getScrollY() + getHeight())) {
//滚动到底部，ScrollView存在回弹效果效应
//优化，只过滤第一次
if (!isScrollToEnd) {
isScrollToEnd = true;
mHandler.sendEmptyMessageDelayed(CODE_TO_END, 200);
Log.e("CustomScrollView", "toEnd,scrollY:" + getScrollY());
mOnScrollChangeListener.onScrollToEnd();
}
}
}
}
}
//滑动监听接口
public interface OnScrollChangeListener {
//滑动到顶部时的回调
void onScrollToStart();
//滑动到底部时的回调
void onScrollToEnd();
}
public void setOnScrollChangeListener(OnScrollChangeListener onScrollChangeListener) {
mOnScrollChangeListener = onScrollChangeListener;
}
}