android 图片浏览器滑动切换图片

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="horizontal" >
    <!-- 定义ImageView控件 -->
    <ImageView
        android:id="@+id/Iv"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:src="@drawable/k1" />
</RelativeLayout>

package com.example.yanlei.yl;

import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
import android.text.Html;
import android.text.Html.ImageGetter;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import android.text.Editable;
import android.text.TextWatcher;
import android.widget.EditText;
import android.widget.Button;

import android.app.Activity;
import android.content.Intent;

import android.view.GestureDetector;
import android.view.MotionEvent;
import android.widget.ImageView;

public class MainActivity extends AppCompatActivity {
    // 定义保存ImageView的对象
    private ImageView Iv;
    //定义手势检测器对象
    private GestureDetector gestureDetector;
    //定义图片的资源数组
    private int[] ResId = new int[]{
            R.drawable.k1,
            R.drawable.k2,
            R.drawable.k3
    };
    //定义当前显示的图片的下标
    private int count = 0;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);
        findView();
        setListener();
    }

    private void setListener() {
        //设置手势监听器的处理效果由onGestureListener来处理
        gestureDetector = new GestureDetector(MainActivity.this,
                onGestureListener);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        //当前Activity被触摸时回调
        return gestureDetector.onTouchEvent(event);
    }

    private void findView() {
        //得到当前页面的imageview控件
        Iv = (ImageView) findViewById(R.id.Iv);
    }
    //定义了GestureDetector的手势识别监听器
    private GestureDetector.OnGestureListener onGestureListener
            = new GestureDetector.SimpleOnGestureListener() {
        //当识别的收拾是滑动手势时回调onFinger方法
        @Override
        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
                               float velocityY) {
            //得到滑动手势的其实和结束点的x，y坐标，并进行计算
            float x = e2.getX() - e1.getX();
            float y = e2.getY() - e1.getY();

            //通过计算结果判断用户是向左滑动或者向右滑动
            if (x > 0) {
                count++;
                count %= 3;
            } else if (x < 0) {
                count--;
                count = (count + 3) % 3;
            }
            //切换imageview的图片
            changeImg();
            return true;
        }
    };

    public void changeImg() {
        //设置当前位置的图片资源
        Iv.setImageResource(ResId[count]);
    }

}