Android 自定义ScrollView的滑动监听事件

项目结构：

1.LazyScrollView类（自定义ScrollView）

package android.zhh.com.myapplicationscrollview;

/**
 * Created by sky on 2017/3/19.
 */

import android.content.Context;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ScrollView;

/**
 * Created by sky on 2017/3/17.
 */
public class LazyScrollView extends ScrollView {
    private static final long DELAY = 100;

    private int currentScroll;

    private Runnable scrollCheckTask;

    /**
     * @param context
     */
    public LazyScrollView(Context context) {
        super(context);
        init();
    }

    /**
     * @param context
     * @param attrs
     */
    public LazyScrollView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    /**
     * @param context
     * @param attrs
     * @param defStyle
     */
    public LazyScrollView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init();
    }

    private void init() {
        scrollCheckTask = new Runnable() {
            @Override
            public void run() {
                int newScroll = getScrollY();
                if (currentScroll == newScroll) {
                    if (onScrollListener != null) {
                        onScrollListener.onScrollStopped();
                    }
                } else {
                    if (onScrollListener != null) {
                        onScrollListener.onScrolling();
                    }
                    currentScroll = getScrollY();
                    postDelayed(scrollCheckTask, DELAY);
                }
            }
        };
        setOnTouchListener(new OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                if (event.getAction() == MotionEvent.ACTION_UP) {
                    currentScroll = getScrollY();
                    postDelayed(scrollCheckTask, DELAY);
                }
                return false;
            }
        });
    }

    public interface OnScrollListener {
        public void onScrollChanged(int x, int y, int oldX, int oldY);

        public void onScrollStopped();

        public void onScrolling();
    }

    private OnScrollListener onScrollListener;

    /**
     * @param onScrollListener
     */
    public void setOnScrollListener(OnScrollListener onScrollListener) {
        this.onScrollListener = onScrollListener;
    }

    @Override
    protected void onScrollChanged(int x, int y, int oldX, int oldY) {
        super.onScrollChanged(x, y, oldX, oldY);
        if (onScrollListener != null) {
            onScrollListener.onScrollChanged(x, y, oldX, oldY);
        }
    }

    /**
     * @param child
     * @return
     */
    public boolean isChildVisible(View child) {
        if (child == null) {
            return false;
        }
        Rect scrollBounds = new Rect();
        getHitRect(scrollBounds);
        return child.getLocalVisibleRect(scrollBounds);
    }

    /**
     * @return
     */
    public boolean isAtTop() {
        return getScrollY() <= 0;
    }

    /**
     * @return
     */
    public boolean isAtBottom() {
        return getChildAt(getChildCount() - 1).getBottom() + getPaddingBottom() == getHeight() + getScrollY();
    }
}

2.activity_main.xml（布局文件中引用）

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    android:orientation="vertical"
    >
    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <android.zhh.com.myapplicationscrollview.LazyScrollView
            android:id="@+id/myScrollView"
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:orientation="vertical"
                >
                <TextView
                    android:layout_width="match_parent"
                    android:layout_height="30dp"
                    android:text="我是zhujiabin"
                    android:gravity="center"
                    />

　　　　　　　　.......
            </LinearLayout>
        </android.zhh.com.myapplicationscrollview.LazyScrollView>

    </RelativeLayout>

</LinearLayout>

3.MainActivity（调用监听事件）

package android.zhh.com.myapplicationscrollview;

import android.app.Activity;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {
//  初始化自定义的ScrollView
    private LazyScrollView myScrollView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        myScrollView = (LazyScrollView)findViewById(R.id.myScrollView);
//      自定义的ScrollView的滑动监听事件
        myScrollView.setOnScrollListener(new LazyScrollView.OnScrollListener() {
            @Override
            public void onScrollChanged(int x, int y, int oldX, int oldY) {
                Log.e("@", "x:" + oldX + "->" + x + ", y:" + oldY + "->" + y);
            }

            @Override
            public void onScrollStopped() {
                if (myScrollView.isAtTop()) {
                    Toast.makeText(MainActivity.this, "Stopped at top", Toast.LENGTH_SHORT).show();
                } else if (myScrollView.isAtBottom()) {
                    Toast.makeText(MainActivity.this, "Stopped at bottom", Toast.LENGTH_SHORT).show();
                } else {
                    Toast.makeText(MainActivity.this, "Stopped", Toast.LENGTH_SHORT).show();
                }
            }

            @Override
            public void onScrolling() {
                Log.e("@", "scrolling...");
            }
        });
    }

}