PHP编程：Yii2创建表单(ActiveForm)方法详解

<?php $form = ActiveForm::begin(['id' => 'login-form']); ?>
  <?= $form->field($model, 'username') ?>
  <?= $form->field($model, 'password')->passwordInput() ?>
  <?= $form->field($model, 'rememberMe')->checkbox() ?>
  <div style="color:#999;margin:1em 0">
   If you forgot your password you can <?= Html::a('reset it', ['site/request-password-reset']) ?>
  </div>
  <div class="form-group">
     <?= Html::submitButton('Login', ['class' => 'btn btn-primary', 'name' => 'login-button']) ?>
  </div>
<?php ActiveForm::end(); ?>

<?php $form = ActiveForm::begin(['id' => 'login-form']); ?>

<?php ActiveForm::end(); ?>

public function init()

public function run()

//这个是在执行 $form = ActiveForm::begin(['id' => 'login-form']); 中的begin方法的时候调用的
public function init()
{
    //设置表单元素form的id
    if (!isset($this->options['id'])) {
      $this->options['id'] = $this->getId();
    }
    //设置表单中间的要生成各个field的所使用的类
    if (!isset($this->fieldConfig['class'])) {
      $this->fieldConfig['class'] = ActiveField::className();
    }
    //这个就是输出表单的开始标签
    //如：<form id="login-form" action="/lulublog/frontend/web/index.php?r=site/login" method="post">
    echo Html::beginForm($this->action, $this->method, $this->options);
}

//这个是在执行 ActiveForm::end(); 中的end方法的时候调用的
public function run()
{
    //下面这个就是往视图中注册表单的js验证脚本,
    if (!empty($this->attributes)) {
      $id = $this->options['id'];
      $options = Json::encode($this->getClientOptions());
      $attributes = Json::encode($this->attributes);
      $view = $this->getView();
      ActiveFormAsset::register($view);
      /*
       * $attributes:为要验证的所有的field数组.它的值是在activeform中创建field的时候,在field的begin方法中给它赋值的.
       * 其中每个field又是一个数组,为这个field的各个参数
       * 比如username的field中的参数有
       * validate、id、name、
       * validateOnChange、validateOnType、validationDelay、
       * container、input、error
       * 
       * $options:为这个表单整体的属性,如：
       * errorSummary、validateOnSubmit、
       * errorCssClass、successCssClass、validatingCssClass、
       * ajaxParam、ajaxDataType
       */
      $view->registerJs("jQuery('#$id').yiiActiveForm($attributes, $options);");
    }
    //输出表单的结束标签
    echo Html::endForm();
}

/*
* 设置表单的全局的一些样式属性以及js回调事件等
*/
protected function getClientOptions()
{
    $options = [
      'errorSummary' => '.' . $this->errorSummaryCssClass,
      'validateOnSubmit' => $this->validateOnSubmit,
      'errorCssClass' => $this->errorCssClass,
      'successCssClass' => $this->successCssClass,
      'validatingCssClass' => $this->validatingCssClass,
      'ajaxParam' => $this->ajaxParam,
      'ajaxDataType' => $this->ajaxDataType,
    ];
    if ($this->validationUrl !== null) {
      $options['validationUrl'] = Url::to($this->validationUrl);
    }
    foreach (['beforeSubmit', 'beforeValidate', 'afterValidate'] as $name) {
      if (($value = $this->$name) !== null) {
        $options[$name] = $value instanceof JsExpression ? $value : new Js$value);
      }
    }
    return $options;
}

jQuery(document).ready(function () {
    jQuery('#login-form').yiiActiveForm(
    {
        "username":{
            "validate":function (attribute, value, messages) {
                yii.validation.required(value, messages, {"message":"Username cannot be blank."});
            },
            "id":"loginform-username",
            "name":"username",
            "validateOnChange":true,
            "validateOnType":false,
            "validationDelay":200,
            "container":".field-loginform-username",
            "input":"#loginform-username",
            "error":".help-block"},
        "password":{
            "validate":function (attribute, value, messages) {
                yii.validation.required(value, messages, {"message":"Password cannot be blank."});
            },
            "id":"loginform-password",
            "name":"password",
            "validateOnChange":true,
            "validateOnType":false,
            "validationDelay":200,
            "container":".field-loginform-password",
            "input":"#loginform-password",
            "error":".help-block"
            },
        "rememberMe":{
            "validate":function (attribute, value, messages) {
                yii.validation.boolean(value, messages, {
                    "trueValue":"1","falseValue":"0","message":"Remember Me must be either \"1\" or \"0\".","skipOnEmpty":1});
            },
            "id":"loginform-rememberme",
            "name":"rememberMe","validateOnChange":true,
            "validateOnType":false,
            "validationDelay":200,
            "container":".field-loginform-rememberme",
            "input":"#loginform-rememberme",
            "error":".help-block"}
    }, 
    {
        "errorSummary":".error-summary",
        "validateOnSubmit":true,
        "errorCssClass":"has-error",
        "successCssClass":"has-success",
        "validatingCssClass":"validating",
        "ajaxParam":"ajax",
        "ajaxDataType":"json"
    });
});

public function errorSummary($models, $options = [])

public static function validate($model, $attributes = null)
public static function validateMultiple($models, $attributes = null)

//这个方法在Widget基本中
public function getId($autoGenerate = true)
{
    if ($autoGenerate && $this->_id === null) {
      $this->_id = self::$autoIdPrefix . self::$counter++;
    }
    return $this->_id;
}

<div class="form-group field-loginform-username required has-error">
    <label class="control-label" for="loginform-username">Username</label>
    <input type="text" id="loginform-username" class="form-control" name="LoginForm[username]">
    <div class="help-block">Username cannot be blank.</div>
</div>

public function field($model, $attribute, $options = [])
{
    //使用fieldConfig和options属性来创建field
    //$options会覆盖统一的fieldConfig属性值,以实现每个field的自定义
    return Yii::createObject(array_merge($this->fieldConfig, $options, [
      'model' => $model,
      'attribute' => $attribute,
      'form' => $this,
]));
}

function ($form) {
 ...return false to cancel submission...
}

function ($form, attribute, messages) {
 ...return false to cancel the validation...
}

function ($form, attribute, messages) {
}