本文實例講述了微信小程序webview實現長按點擊識別二維碼功能。分享給大家供大家參考，具體如下：

場景：微信小程序，使用webview控件。需求：點擊圖片后長按圖片出現“識別二維碼”

1、JS代碼：

<script src="http://res.wx.qq.com/open/js/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, //調試階段建議開啟      appId: appId,      timestamp: timestamp,      nonceStr: nonceStr,      signature: signature,      jsApiList: [          /*          * 所有要調用的 API 都要加到這個列表中          * 這里以圖像接口為例          */         "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, // 當前顯示圖片的http鏈接              urls: [url] // 需要預覽的圖片http鏈接列表            });          });      });      wx.error(function(res){        // config信息驗證失敗會執行error函數，如簽名過期導致驗證失敗，具體錯誤信息可以打開config的debug模式查看，也可以在返回的res參數中查看，對于SPA可以在這里更新簽名。        console.log(res);      });});</script>

2、服務端代碼（獲取config配置信息）：

<?phpdate_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 一定要動態獲取，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();    // 這里參數的順序要按照 key 值 ASCII 碼升序排序    $string = "jsapi_ticket=$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 應該全局存儲與更新，以下代碼以寫入到文件中做示例    $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();      // 如果是企業號用以下 URL 獲取 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 應該全局存儲與更新，以下代碼以寫入到文件中做示例    $data = $this->get_php_file("access_token");    if (!isset($data['access_token']) || (isset($data['expire_time']) && $data['expire_time'] < time())) {      // 如果是企業號用以下URL獲取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($curl, CURLOPT_TIMEOUT, 500);    // 為保證第三方服務器與微信服務器之間數據傳輸的安全性，所有微信接口采用https方式調用，必須使用下面2行代碼打開ssl安全校驗。    // 如果在部署過程中代碼在此處驗證失敗，請到 http://curl.haxx.se/ca/cacert.pem 下載新的證書判別文件。    curl_setopt($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);  }}