客套话就不多说了，直接上教程
照例声明，对于第三篇与前篇篇中类似的部分不会太过于详述。觉得不够详细的部分可以参考第一篇。附上链接yii2博客项目笔记（一），yii2博客项目笔记（二）。
初步分析
- 本篇讲述博客评论功能的实现，并支持对评论回复。
- 数据库设计为评论表和回复表。
一、数据库建立
命令行执行 .\yii migrate/create comment 创建 comment 数据表，然后修改目录 console\migrations 下生成的文件内容如下：
<?php
use yii\db\Migration;
class m160825_032145_comment extends Migration
{
public function up()
{
$tableOptions = null;
if ($this->db->driverName === 'mysql') {
// http://stackoverflow.com/questions/766809/whats-the-difference-between-utf8-general-ci-and-utf8-unicode-ci
$tableOptions = 'CHARACTER SET utf8 COLLATE utf8_unicode_ci ENGINE=InnoDB';
}
$this->createTable('{{%comment}}', [
'id' => $this->primaryKey(),
'post_id' => $this->integer()->notNull(),
'comment' => $this->string(),
'status' => $this->integer(1)->notNull()->defaultValue(1),
'created_at' => $this->integer()->notNull(),
'updated_at' => $this->integer()->notNull(),
], $tableOptions);
$this->createIndex(
'idx-comment-post_id',
'comment',
'post_id'
);
$this->createIndex(
'idx-comment-created_at_id',
'comment',
'created_at'
);
}
public function down()
{
echo "m160825_032145_comment cannot be reverted.\n";
return false;
}
/*
// Use safeUp/safeDown to run migration code within a transaction
public function safeUp()
{
}
public function safeDown()
{
}
*/
}
命令行执行 .\yii migrate/create reply 创建 reply 数据表，然后修改目录 console\migrations 下生成的文件内容如下：
<?php
use yii\db\Migration;
class m160825_032215_reply extends Migration
{
public function up()
{
$tableOptions = null;
if ($this->db->driverName === 'mysql') {
// http://stackoverflow.com/questions/766809/whats-the-difference-between-utf8-general-ci-and-utf8-unicode-ci
$tableOptions = 'CHARACTER SET utf8 COLLATE utf8_unicode_ci ENGINE=InnoDB';
}
$this->createTable('{{%reply}}', [
'id' => $this->primaryKey(),
'comment_id' => $this->integer()->notNull(),
'reply' => $this->string(),
'status' => $this->integer(1)->notNull()->defaultValue(1),
'created_at' => $this->integer()->notNull(),
'updated_at' => $this->integer()->notNull(),
], $tableOptions);
$this->createIndex(
'idx-reply-comment_id',
'reply',
'comment_id'
);
$this->createIndex(
'idx-reply-created_at_id',
'reply',
'created_at'
);
}
public function down()
{
echo "m160825_032215_reply cannot be reverted.\n";
return false;
}
/*
// Use safeUp/safeDown to run migration code within a transaction
public function safeUp()
{
}
public function safeDown()
{
}
*/
}
然后在命令行输入 .\yii migrate 数据表就建立完成了，详细操作看yii2博客项目笔记（一）。
数据表的增删改查
打开 Gii 工具。选择 Model Generator。依次建立 comment 和 reply 模型。Namespace 选择 common\models。之后向生成的两个文件添加 TimestampBehavior 行为。
然后选择CRUD Generator，生成 comment 和 reply 表的增删改查。详细操作看yii2博客项目笔记（一）。
由于删除评论时也要删除评论的回复，所以打开 backend\controllers\CommentController 。添加use common\models\Reply;命名空间。修改actionDelete方法为
public function actionDelete($id)
{
$this->findModel($id)->delete();
Reply::deleteAll('comment_id > :comment_id', [':comment_id' => $id]);
return $this->redirect(['index']);
}
前台显示
评论是显示在文章列表的，打开 frontend/controllers/PostController.php 修改actionItem方法如下
public function actionItem($id)
{
$post = Posts::findOne($id);
$tags = $post->tags;
$comments = Comment::findAll([
'post_id' => $id,
'status' => 1]); //获得该文章所有 status 为 1 的评论
$replys = array();
foreach ($comments as $comment) {
$replys[$comment->id] = Reply::findAll(['comment_id' => $comment->id,'status' => 1]); //根据评论 id 查找所有 status 为 1 的评论，并赋值给$replys数组，
}
return $this->render('item',[
'post'=>$post,
'tags'=>$tags,
'comments'=>$comments, //传递变量到前台
'replys' => $replys
]);
}
接着修改 frontend/views/post/item.php 内容如下。
<?php
/* @var $this yii\web\View */
use yii\helpers\Html;
$this->title = $post->title;
$this->params['breadcrumbs'][] = ['label' => 'Posts', 'url' => ['index']];
$this->params['breadcrumbs'][] = $this->title;
?>
<h1><?php echo $post->title; ?></h1>
<p class="text-muted">作者：<?php echo $post->author; ?> 标签:<?php foreach ($tags as $tags) {
echo "<kbd>".$tags['tag']."</kbd> ";
} ?></p>
<p>
<?php echo yii\helpers\Markdown::process($post->content, 'gfm'); ?>
</p>
<div class="panel panel-default">
<div class="panel-heading">评论</div>
<div class="panel-body">
<ul class="media-list">
<?php $i = 0; foreach ($comments as $comment) //循环输出所有评论 ?>
<li class="media">
<div class="media-body">
<h4 class="media-heading"><?php echo '第'.++$i.'楼'; ?></h4>
<?php echo yii\helpers\Markdown::process($comment->comment, 'gfm');?>
</div>
</li>
<?php
if ($reply = $replys[$comment->id]) {
echo "<hr>";
foreach ($reply as $reply ) { //如果评论有回复，循环输出所有回复
?>
<div style="margin-left:30px;"><?php echo yii\helpers\Markdown::process($reply->reply, 'gfm');?></div>
<?php }} ?>
<a href="javascript:void(0)" onclick="reply(this,<?php echo $comment->id;?>)" style="margin-left:30px;" >回复</a>
<hr>
<?php } ?>
</ul>
</div>
</div>
<?php //评论表单 ?>
<?= Html::beginForm(['comment/add', 'id' => $post->id], 'post') ?>
<h4>输入评论内容</h4>
<?= \yidashi\markdown\Markdown::widget(['name' => 'comment', 'language' => 'zh'])?>
<br>
<?= Html::submitButton('提交', ['class' => 'btn btn-primary']) ?>
<?= Html::endForm() ?>
<?php //回复表单 ?>
<div class="hidden" id="reply" style="margin-left:30px;">
<br>
<?= Html::beginForm(['reply/add'], 'post') ?>
<?= Html::hiddenInput('comment_id', 0, ['id' => 'comment_id']);?>
<?= \yidashi\markdown\Markdown::widget(['name' => 'reply', 'language' => 'zh'])?>
<br>
<?= Html::submitButton('提交', ['class' => 'btn btn-primary']) ?>
<?= Html::endForm() ?>
</div>
<script type="text/javascript">
function reply(reply,comment_id){ //显示回复内容输入框，参数为该元素，和评论id
$('#comment_id').val(comment_id); //修该表单 comment_id 的值为该评论的 id
$('#reply').removeClass('hidden'); //显示回复输入框
$(reply).after($('#reply')); //将回复框移到该元素之后
}
</script>
然后新建 frontend/controllers/CommentController.php，内容为下。
<?php
namespace frontend\controllers;
use common\models\Comment;
use Yii;
class CommentController extends \yii\web\Controller
{
public function actionAdd($id)
{
$comment = new Comment();
$comment ->post_id = $id;
$comment->comment = Yii::$app->request->post('comment');
if ($comment->save()) {
return $this->redirect(Yii::$app->request->referrer);
}
echo "string";
}
}
新建 frontend/controllers/ReplyController.php，内容为下。
<?php
namespace frontend\controllers;
use Yii;
use common\models\Reply;
class ReplyController extends \yii\web\Controller
{
public function actionAdd()
{
$reply = new Reply();
$reply ->comment_id = Yii::$app->request->post('comment_id');
$reply->reply = Yii::$app->request->post('reply');
if ($reply->save()) {
return $this->redirect(Yii::$app->request->referrer);
}
}
}
附上效果图一张，前台未美化，较丑，多见谅
总结
关于评论的功能实现了，再过几天就开学了，课程比较多，博客开发可能就这了，不会在更新了。
本文由 stoneyang 创作，采用 知识共享署名 3.0 中国大陆许可协议 进行许可。 可自由转载、引用，但需署名作者且注明文章出处。
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