yii2上传图片的代码讲解

.onedialog{position:absolute; left: 300px; top: 500px; z-index: 10; width: 700px; height: 400px;border-radius:5px;box-shadow:5px 2px 6px #000; border: 2px solid #666}
.oneiframe{ width: 100%; height: 100% }

$(function(){
 $('#product-picurl').click(function(){
 $('#oneupload').remove();
 $('<div>').appendTo($('body')).attr({"class":"onedialog",'id':"oneupload"});
 $('<iframe>').appendTo($('#oneupload')).attr({"src":"?r=upload","class":"oneiframe"})
 });
  var v=$('#product-picurl').val();
 if(v){
 $('<img>').attr({"src":v,"style":"height:50px"}).insertAfter($('#product-picurl'));
 }
});

class AppAsset extends AssetBundle
{
  public $basePath = '@webroot';
  public $baseUrl = '@web';
  public $css = [
    'css/site.css',
    'css/main.css',
  ];
  public $js = [
    'assets/main.js'
  ];
  public $depends = [
    'yii\web\YiiAsset',
    'yii\bootstrap\BootstrapAsset',
  ];
}

<?PHP
namespace frontend\controllers;

use Yii;
use yii\web\Controller;
use app\models\UploadForm;
use yii\web\UploadedFile;

class UploadController extends Controller
{
  public function actionIndex()
  {
    $model = new UploadForm();

    if (Yii::$app->request->isPost) {
      $model->file = UploadedFile::getInstance($model, 'file');

      if ($model->file && $model->validate()) {
        //$model->file->saveAs('uploads/' . $model->file->baseName . '.' . $model->file->extension);      
        $fileName='uploads/' . date("YmdHis") . '.' . $model->file->extension;
        $model->file->saveAs($fileName);
      }
      echo "<script src='assets/upload.js'></script>;";
      echo "<script>";
      echo "var oneinput=parent.document.getElementById('product-picurl');";
      echo "parent.document.getElementById('product-picurl').value='".$fileName."';";
      echo "var oneupload = parent.document.getElementById('oneupload');";
      echo "var img = document.createElement('img');";
      echo "img.setAttribute('style', 'height:50px');";
      echo "img.src ='".$fileName."';";
      echo "insertAfter(img,oneinput);";
      echo "oneupload.parentNode.removeChild(oneupload)";
      echo "</script>";
    }

    return $this->render('upload', ['model' => $model]);
  }
}
?>

<?PHP
namespace app\models;

use yii\base\Model;
use yii\web\UploadedFile;

/**
 * UploadForm is the model behind the upload form.
 */
class UploadForm extends Model
{
  /**
   * @var UploadedFile file attribute
   */
  public $file;

  /**
   * @return array the validation rules.
   */
  public function rules()
  {
    return [
      [['file'], 'file'],
    ];
  }
}
?>

<?php
use yii\widgets\ActiveForm;
?>

<?php $form = ActiveForm::begin(['options' => ['enctype' => 'multipart/form-data']]) ?>

<?= $form->field($model, 'file')->fileInput() ?>

<button>Submit</button>

<?php ActiveForm::end() ?>