Laravel 创建默认类别为“”的新帖子

我有一个职位/类别很多关系，希望能够附加一个名为“未分类”的默认类别到每个新创建的职位。我该怎么做？BelongToMany方法仅在“详细信息”页面上有效，而不在“创建”页面上有效

BelongsToMany::make(__('Categories'), 'categories', Category::class),

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您还可以将默认值设置为数据库字段，这样您就可以忽略传递类别，并将默认值设置为未分类，就像您使用MySQL一样，您可以通过创建迁移来实现这一点

$table->text('category')->default(0);

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因为在后新星模型中创建的“BelongTomany未在模式上显示”。因此，我们必须通过将以下代码添加到您的字段来进行自定义选择：

public function fields(Request $request)
{
    if($request->editMode=="create"){
        $categories = \App\Category::get(['id','name']);
        $options = [];
        foreach($categories as $value){
            $options[$value->id] = $value->name;
        }
        return [
            ID::make()->sortable(),
            Text::make('Title'),
            Text::make('Summary'),
            Textarea::make('Content'),
            Select::make('Categories', 'category_id')
            ->options($options)
            ->displayUsingLabels()
            ->withMeta(['value' => 1]) // 1 = id of Uncategorised in categories table
        ];
    }
    return [
        ID::make()->sortable(),
        Text::make('Title'),
        Text::make('Summary'),
        Textarea::make('Content'),
        BelongsToMany::make('Categories','categories')->display('name'),
    ];
}

不要忘记在Post和Category模型中的关系函数：

class Post extends Model
{
    public function categories(){
        return $this->belongsToMany(Category::class, 'category_post', 'post_id', 'category_id');
    }
}

以及：

然后，自定义函数在Post资源页面的创建模式下处理数据，位于nova\src\Http\Controllers\ResourceStoreController.php，将函数句柄更改为：

    public function handle(CreateResourceRequest $request)
    {
        $resource = $request->resource();

        $resource::authorizeToCreate($request);

        $resource::validateForCreation($request);

        $model = DB::transaction(function () use ($request, $resource) {
            [$model, $callbacks] = $resource::fill(
                $request, $resource::newModel()
            );

            if ($request->viaRelationship()) {
                $request->findParentModelOrFail()
                        ->{$request->viaRelationship}()
                        ->save($model);
            } else {
                $model->save();
                // your code to save to pivot category_post here
                if(isset($request->category_id)&&($resource=='App\Nova\Post')){
                    $category_id = $request->category_id;
                    $post_id = $model->id;
                    \App\Post::find($post_id)->categories()->attach($category_id);
                }
            }

            ActionEvent::forResourceCreate($request->user(), $model)->save();

            collect($callbacks)->each->__invoke();

            return $model;
        });

        return response()->json([
            'id' => $model->getKey(),
            'resource' => $model->attributesToArray(),
            'redirect' => $resource::redirectAfterCreate($request, $request->newResourceWith($model)),
        ], 201);
    }
}

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我的电脑运行良好。一个有趣的问题！希望你一切顺利，如果你需要的话请告诉我

我最后做的是将Post模型上的数据保存在boot（）中

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“BelongToMany方法只在“详细信息”页面有效，而不在“创建”页面有效。“你这么说是什么意思，这种关系将始终有效？@MartinHenriksen是的，这是正确的。我不知道你在问我什么？这也是一种很好的方法Hanks@protoproto，我还没有测试过你的解决方案，但是谢谢你的帮助。是的，想得大点，做得最好！：D

    public function handle(CreateResourceRequest $request)
    {
        $resource = $request->resource();

        $resource::authorizeToCreate($request);

        $resource::validateForCreation($request);

        $model = DB::transaction(function () use ($request, $resource) {
            [$model, $callbacks] = $resource::fill(
                $request, $resource::newModel()
            );

            if ($request->viaRelationship()) {
                $request->findParentModelOrFail()
                        ->{$request->viaRelationship}()
                        ->save($model);
            } else {
                $model->save();
                // your code to save to pivot category_post here
                if(isset($request->category_id)&&($resource=='App\Nova\Post')){
                    $category_id = $request->category_id;
                    $post_id = $model->id;
                    \App\Post::find($post_id)->categories()->attach($category_id);
                }
            }

            ActionEvent::forResourceCreate($request->user(), $model)->save();

            collect($callbacks)->each->__invoke();

            return $model;
        });

        return response()->json([
            'id' => $model->getKey(),
            'resource' => $model->attributesToArray(),
            'redirect' => $resource::redirectAfterCreate($request, $request->newResourceWith($model)),
        ], 201);
    }
}

public static function boot()
{
    parent::boot();

    static::created(function (Post $post) {

        $post->categories()->attach([1]);

    });
}