判断微信是否登录

 //判断是否安装微信客户端
    if (![WXApi isWXAppInstalled]) {//没有安装微信客户端,隐藏微信登陆的按钮
        self.buttongWidth.constant = UI_SCREEN_WIDTH * 0.5;
       
    }else {
       self.buttongWidth.constant = UI_SCREEN_WIDTH * (1/3);

    }