public function actions()

    {

        return [

            'captcha' => [

                'class' => 'yii\captcha\CaptchaAction',

                'fixedVerifyCode' => YII_ENV_TEST ? 'testme' : null,

            ],

        ];

    }

2.模型中

要有一个验证码的字段$verifyCode

3.视图中

use yii\helpers\Html; use yii\widgets\ActiveForm; use yii\captcha\Captcha;

自动生成表单

 

页面中验证码代码

<?= $form->field($model, 'verifyCode')->widget(Captcha::className(), [                     'template' => '<div class="row"><div class="col-lg-3">{image}</div><div class="col-lg-6">{input}</div></div>', ]) ?>

控制器中的权限可能导致验证码图片不显示，

public function behaviors()     {         return [             'access' => [                 'class' => AccessControl::className(),                  'only' => ['logout', 'signup','login'],                 'rules' => [                     [                         'actions' => ['signup'],                         'allow' => true,                         'roles' => ['?'],                     ],                     [                         'actions' => ['logout'],                         'allow' => true,                         'roles' => ['@'],                     ],                 ],             ],             'verbs' => [                 'class' => VerbFilter::className(),                 'actions' => [                     'logout' => ['post'],                 ],             ],         ];     }

控制器中红线部分缺少则导致验证码不显示