设备系统识别，解决方案。

//检测相关的设备型号
	var mobileUAKeywords = ["nokia", "sony", "ericsson", "mot", "samsung", "htc", "sgh", "lg", "sharp", "sie-",
	                        "philips", "panasonic", "alcatel", "lenovo", "iphone", "ipod", "blackberry", "meizu", 
	                        "android", "netfront", "symbian", "ucweb", "windowsce", "palm", "operamini", 
	                        "operamobi", "opera mobi", "openwave", "nexusone", "cldc", "midp", "wap", "mobile"
	                    ];
    var userAgent = navigator.userAgent;
    var regExp = new RegExp(mobileUAKeywords.join("|"), "i");
    var browser = {
        mobile: !!userAgent.match(regExp),
        android: /android/i.test(userAgent) || /linux/i.test(userAgent),
        iPad: /iPad/i.test(userAgent),
        iphone: /iphone/i.test(userAgent),
        ipod: /ipod/i.test(userAgent),
        isWechatBrowser: /micromessenger/i.test(userAgent)
    };
    
    //初始化型号设备为false，不显示按钮
    $scope.android = false;
    $scope.ios = false;
    $scope.wx = false;
    /*$scope.ios = browser.iphone*/
    if (browser.android) {
    	$scope.android = true;
    } else if(browser.iphone || browser.ipod || browser.iPad){
    	 $scope.ios = true;
    }
     //判断是否是微信
    if (browser.isWechatBrowser) {
    	$scope.wx = true;
    }