微信小程序webview实现长按点击识别二维码功能示例

<script src="https://cdn.zhanzhang360.cn/imgupload/004651/jweixin-1.2.0.js"></script>
<script type="text/javascript">
$(function(){
  var returnData = false;
  $.ajax({
   type  : "get",
   url  : 'http://app.ka.com/m/config.php',
   data  : [],
   async  : false,
   success: function(data,textStatus,jqXHR){
        returnData = data;
        //console.log(returnData);
      }
  });//end ajax
  var returnData = eval('(' + returnData + ')');
  console.log(returnData);
  var appId     = returnData.appId;
  var timestamp   = returnData.timestamp;
  var nonceStr   = returnData.nonceStr;
  var signature   = returnData.signature;
     wx.config({
      debug: true, //调试阶段建议开启
      appId: appId,
      timestamp: timestamp,
      nonceStr: nonceStr,
      signature: signature,
      jsApiList: [
          /*
          * 所有要调用的 API 都要加到这个列表中
          * 这里以图像接口为例
          */
         "chooseImage",
         "previewImage",
         "uploadImage",
         "downloadImage",
         "scanQRCode"
      ]
     });
      wx.ready(function() {
      //alert(3);
        wx.checkJsApi({
           jsApiList : ['scanQRCode','previewImage'],
           success : function(res) {
           }
        });
          $("img").click(function(){
            var url = "http://app.ka.com/"+$(this).attr("src");
            wx.previewImage({
              current: url, // 当前显示图片的http链接
              urls: [url] // 需要预览的图片http链接列表
            });
          });
      });
      wx.error(function(res){
        // config信息验证失败会执行error函数，如签名过期导致验证失败，具体错误信息可以打开config的debug模式查看，也可以在返回的res参数中查看，对于SPA可以在这里更新签名。
        console.log(res);
      });
});
</script>

<?php
date_default_timezone_set("Asia/Shanghai");
$jssdk = new Jssdk();
$signPackage = $jssdk->getSignPackage();
echo json_encode($signPackage);exit;
class Jssdk
{
  private $_CI;
  private $appId;
  private $appSecret;
  public function __construct($appId='wx666666', $appSecret='ee32') {
    $this->appId = $appId;
    $this->appSecret = $appSecret;
  }
  public function getSignPackage() {
    $jsapiTicket = $this->getJsApiTicket();
    // 注意 URL 一定要动态获取，不能 hardcode.
    $protocol = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off' || $_SERVER['SERVER_PORT'] == 443) ? "https://" : "http://";
    $url = "$protocol$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";
    $timestamp = time();
    $nonceStr = $this->createNonceStr();
    // 这里参数的顺序要按照 key 值 ASCII 码升序排序
    $string = "jsapi_ticket=$jsapiTicket&noncestr=$nonceStr×tamp=$timestamp&url=$url";
    $signature = sha1($string);
    $signPackage = array(
      "appId"   => $this->appId,
      "nonceStr" => $nonceStr,
      "timestamp" => $timestamp,
      "url"    => $url,
      "signature" => $signature,
      "rawString" => $string,
      'jsapiTicket' =>$jsapiTicket,
    );
    return $signPackage;
  }
  private function createNonceStr($length = 16) {
    $chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
    $str = "";
    for ($i = 0; $i < $length; $i++) {
      $str .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
    }
    return $str;
  }
  private function getJsApiTicket() {
    // jsapi_ticket 应该全局存储与更新，以下代码以写入到文件中做示例
    $data = $this->get_php_file("jsapi_ticket");
    //echo $data['expire_time'].'------'.time();
    //print_r($data);exit;
    if (!isset($data['jsapi_ticket']) || (isset($data['expire_time']) && $data['expire_time'] < time())) {
      //echo 1111;
      $accessToken = $this->getAccessToken();
      // 如果是企业号用以下 URL 获取 ticket
      // $url = "https://qyapi.weixin.qq.com/cgi-bin/get_jsapi_ticket?access_token=$accessToken";
      $url = "https://api.weixin.qq.com/cgi-bin/ticket/getticket?type=jsapi&access_token=$accessToken";
      //echo $url;
      $res = json_decode($this->httpGet($url), true);
      $ticket = isset($res['ticket']) ? $res['ticket'] : false;
      if ($ticket) {
        $data['expire_time'] = time() + 7160;
        $data['token_value'] = $ticket;
        $this->set_php_file("jsapi_ticket", $data);
      }
    } else {
      //echo 22222;
      $ticket = $data['jsapi_ticket'];
    }
    return $ticket;
  }
  public function getAccessToken() {
    // access_token 应该全局存储与更新，以下代码以写入到文件中做示例
    $data = $this->get_php_file("access_token");
    if (!isset($data['access_token']) || (isset($data['expire_time']) && $data['expire_time'] < time())) {
      // 如果是企业号用以下URL获取access_token
      // $url = "https://qyapi.weixin.qq.com/cgi-bin/gettoken?corpid=$this->appId&corpsecret=$this->appSecret";
      $url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=$this->appId&secret=$this->appSecret";
      $res = json_decode($this->httpGet($url));
      //var_dump($res);exit;
      $access_token = $res->access_token;
      if ($access_token) {
        $data['expire_time'] = time() + 7160;
        $data['token_value'] = $access_token;
        $this->set_php_file("access_token", $data);
      }
    } else {
      $access_token = $data['access_token'];
    }
    return $access_token;
  }
  private function httpGet($url) {
    $curl = curl_init();
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($curl, CURLOPT_TIMEOUT, 500);
    // 为保证第三方服务器与微信服务器之间数据传输的安全性，所有微信接口采用https方式调用，必须使用下面2行代码打开ssl安全校验。
    // 如果在部署过程中代码在此处验证失败，请到 http://curl.haxx.se/ca/cacert.pem 下载新的证书判别文件。
    curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, 0);
    curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, 0);
    curl_setopt($curl, CURLOPT_URL, $url);
    $res = curl_exec($curl);
    curl_close($curl);
    return $res;
  }
  private function get_php_file($token_name) {
    if(file_exists($token_name)) return false;
    return json_decode(file_get_contents($token_name), true);
  }
  private function set_php_file($token_name, $data) {
    $fp = fopen($token_name, "w");
    fwrite($fp, "<?php exit();?>" . json_encode($data));
    fclose($fp);
  }
}