首先要先注册长按监听菜单private String imgurl = "";    /***     * 功能：长按图片保存到手机     */    @Override    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {        super.onCreateContextMenu(menu, v, menuInfo);        MenuItem.OnMenuItemClickListener handler = new MenuItem.OnMenuItemClickListener() {            public boolean onMenuItemClick(MenuItem item) {                if (item.getTitle() == "保存到手机") {                    new SaveImage().execute(); // Android 4.0以后要使用线程来访问网络                } else {                    return false;                }                return true;            }        };        if (v instanceof WebView) {            WebView.HitTestResult result = ((WebView) v).getHitTestResult();            if (result != null) {                int type = result.getType();                if (type == WebView.HitTestResult.IMAGE_TYPE || type == WebView.HitTestResult.SRC_IMAGE_ANCHOR_TYPE) {                    imgurl = result.getExtra();                    menu.setHeaderTitle("提示");                    menu.add(0, v.getId(), 0, "保存到手机").setOnMenuItemClickListener(handler);                }            }        }    }    /***     * 功能：用线程保存图片     *      * @author wangyp     *      */    private class SaveImage extends AsyncTask
     
       {        @Override        protected String doInBackground(String... params) {            String result = "";            try {                String sdcard = Environment.getExternalStorageDirectory().toString();                File file = new File(sdcard + "/Download");                if (!file.exists()) {                    file.mkdirs();                }                int idx = imgurl.lastIndexOf(".");                String ext = imgurl.substring(idx);                file = new File(sdcard + "/Download/" + new Date().getTime() + ext);                InputStream inputStream = null;                URL url = new URL(imgurl);                HttpURLConnection conn = (HttpURLConnection) url.openConnection();                conn.setRequestMethod("GET");                conn.setConnectTimeout(20000);                if (conn.getResponseCode() == 200) {                    inputStream = conn.getInputStream();                }                byte[] buffer = new byte[4096];                int len = 0;                FileOutputStream outStream = new FileOutputStream(file);                while ((len = inputStream.read(buffer)) != -1) {                    outStream.write(buffer, 0, len);                }                outStream.close();                result = "图片已保存至：" + file.getAbsolutePath();            } catch (Exception e) {                result = "保存失败！" + e.getLocalizedMessage();            }            return result;        }        @Override        protected void onPostExecute(String result) {            MsgBox("提示", result);        }    }