Android点击WebView实现图片缩放及滑动浏览效果

webView = (WebView) findViewById(R.id.webview);
  webView.loadUrl(url);
  WebSettings settings = webView.getSettings();

  //设置屏幕适应
  settings.setLayoutAlgorithm(WebSettings.LayoutAlgorithm.NARROW_COLUMNS);
  settings.setUseWideViewPort(true);
  settings.setLoadWithOverviewMode(true);

  //防止中文乱码
  settings.setDefaultTextEncodingName("UTF -8");
  settings.setJavaScriptEnabled(true);
  //载入js
  webView.addJavascriptInterface(new JavascriptInterface(this), "imagelistner");

  webView.setWebViewClient(new WebViewClient() {
   // 网页跳转
   @Override
   public boolean shouldOverrideUrlLoading(WebView view, String url) {
    view.loadUrl(url);
    return super.shouldOverrideUrlLoading(view, url);
   }

   // 网页加载结束
   @Override
   public void onPageFinished(WebView view, String url) {
    super.onPageFinished(view, url);

    // html加载完成之后，添加监听图片的点击js函数
    addImageClickListner();
   }
  });

 // 注入js函数监听
 private void addImageClickListner() {
  //遍历页面中所有img的节点，因为节点里面的图片的url即objs[i].src，保存所有图片的src.
  //为每个图片设置点击事件，objs[i].onclick
  webView.loadUrl("javascript:(function(){" +
    "var objs = document.getElementsByTagName(\"img\"); " +
    "for(var i=0;i<objs.length;i++) " +
    "{" +
    "window.imagelistner.readImageUrl(objs[i].src); " +
    " objs[i].onclick=function() " +
    " { " +
    " window.imagelistner.openImage(this.src); " +
    " } " +
    "}" +
    "})()");
 }

 // js通信接口
 public class JavascriptInterface {

  private Context context;

  public JavascriptInterface(Context context) {
   this.context = context;
  }

  @android.webkit.JavascriptInterface
  public void readImageUrl(String img) {  //把所有图片的url保存在ArrayList<String>中
   images.add(img);
  }

  @android.webkit.JavascriptInterface //对于targetSdkVersion>=17的，要加这个声明
  public void openImage(String clickimg)//点击图片所调用到的函数
  {
   int index = 0;
   ArrayList<String> list = addImages();
   for (String url : list)
    if (url.equals(clickimg)) index = list.indexOf(clickimg);//获取点击图片在整个页面图片中的位置
   Intent intent = new Intent();
   Bundle bundle = new Bundle();
   bundle.putStringArrayList("list_image", list);
   bundle.putInt("index", index);
   intent.putExtra("bundle", bundle);//将所有图片的url以及点击图片的位置作为参数传给启动的activity
   intent.setClass(context, ShowWebImageActivity.class);
   context.startActivity(intent);//启动ViewPagerActivity,用于显示图片
  }
 }

 //去重复
 private ArrayList<String> addImages() {
  ArrayList<String> list = new ArrayList<>();
  Set set = new HashSet();
  for (String cd:images) {
   if(set.add(cd)){
    list.add(cd);
   }
  }
  return list;
 }

public class ShowWebImageActivity extends AppCompatActivity{

 private ArrayList<String> images;

 @Override
 protected void onCreate(@Nullable Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_show_webimage);
  HackyViewPager hackyViewPager = (HackyViewPager) findViewById(R.id.view_pager);

  Bundle bundle = getIntent().getBundleExtra("bundle");
  images = bundle.getStringArrayList("list_image");
  int index = bundle.getInt("index");
  hackyViewPager.setAdapter(new ViewPagerAdapter());
  hackyViewPager.setCurrentItem(index);

 }

 class ViewPagerAdapter extends PagerAdapter{

  @Override
  public int getCount() {
   return images.size();
  }

  @Override
  public boolean isViewFromObject(View view, Object object) {
   return view == object;
  }

  @Override
  public Object instantiateItem(ViewGroup container, int position) {
   View view = View.inflate(ShowWebImageActivity.this,R.layout.view_pager_item,null);
   PhotoView photoView = (PhotoView) view.findViewById(R.id.photoview);
   TextView indicator = (TextView) view.findViewById(R.id.indicator);
   //用Glide加载图片
   Glide.with(ShowWebImageActivity.this).load(images.get(position)).into(photoView);
   CharSequence text = getString(R.string.viewpager_indicator, position+1, images.size());
   //设置indicator
   indicator.setText(text);
   container.addView(view, ViewPager.LayoutParams.MATCH_PARENT, ViewPager.LayoutParams.MATCH_PARENT);
   return view;
  }

  @Override
  public void destroyItem(ViewGroup container, int position, Object object) {
   container.removeView((View) object);
  }
 }
}

public class HackyViewPager extends ViewPager {
 private boolean isLocked;
 public HackyViewPager(Context context) {
  super(context);
  isLocked = false;
 }
 public HackyViewPager(Context context, AttributeSet attrs) {
  super(context, attrs);
  isLocked = false;
 }
 @Override
 public boolean onInterceptTouchEvent(MotionEvent ev) {//用于处理Touch事件
  if (!isLocked) {
   try {
    return super.onInterceptTouchEvent(ev);
   } catch (IllegalArgumentException e) {
    e.printStackTrace();
    return false;
   }
  }
  return false;
 }
 @Override
 public boolean onTouchEvent(MotionEvent event) {
  return !isLocked && super.onTouchEvent(event);
 }
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 >

 <uk.co.senab.photoview.PhotoView
  android:id="@+id/photoview"
  android:layout_width="match_parent"
  android:layout_height="match_parent" />

 <TextView
  android:id="@+id/indicator"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:layout_alignParentBottom="true"
  android:gravity="center"
  android:textSize="18sp"
  android:textColor="@android:color/black"
  android:text="@string/viewpager_indicator"
  android:background="@android:color/transparent" />

</RelativeLayout>

<string name="viewpager_indicator">%1$d/%2$d</string>