Question

有人能让这段代码更好吗？我的问题在于我需要＆＃34; protein，kh和fat＆＃34;是optionals。但NSNumber不接受选项作为参数。所以我必须做这个非常难看的东西。还有更好的方法吗？

@IBAction func save(){
    if nameLabel.text.isEmpty {
        Toast.showToast("Name cannot be empty.", view: view)
    } else {
        let kcal = kcalLabel.text.toInt()
        let protein = proteinLabel.text.toDouble() // returns Double?
        let kh = khLabel.text.toDouble() // returns Double?
        let fat = fatLabel.text.toDouble() // returns Double?
        foodItem.name = nameLabel.text
        foodItem.kcal = kcal == nil ? nil : NSNumber(integer: kcal!)
        foodItem.protein = protein == nil ? nil : NSNumber(double: protein!)
        foodItem.kh = kh == nil ? nil : NSNumber(double: kh!)
        foodItem.fat = fat == nil ? nil : NSNumber(double: fat!)
        foodItem.remarks = remarksLabel.text
        foodItem.requireUpdate = NSNumber(bool: true)
        foodItem.isdeleted = NSNumber(bool: false)
        delegate.addFoodItemViewController(self, didAddFoodItem: foodItem)
        Toast.showToast("FoodItem saved.", view: view)
    }
}

以下是模型：

class FoodItem: NSManagedObject {

    @NSManaged var name: String
    @NSManaged var kcal: NSNumber?
    @NSManaged var kh: NSNumber?
    @NSManaged var protein: NSNumber?
    @NSManaged var fat: NSNumber?
    @NSManaged var remarks: String?
    @NSManaged var isdeleted: NSNumber
    @NSManaged var requireUpdate: NSNumber
    @NSManaged var displayOrder: NSNumber
    @NSManaged var uid: String?

}

Answer 1

您可以添加一些扩展方法来清理语法：

foodItem.kcal = kcal?.toNSNumber()
foodItem.protein = protein?.toNSNumber()

然后：

<?php

function myplugin_add_meta_box() {

$screens = array( 'post', 'page' );

foreach ( $screens as $screen ) {

    add_meta_box(
        'myplugin_sectionid',
        __( 'My Post Section Title', 'myplugin_textdomain' ),
        'myplugin_meta_box_callback',
        $screen
    );
 }
}
add_action( 'add_meta_boxes', 'myplugin_add_meta_box' );

function myplugin_meta_box_callback( $post ) {
wp_nonce_field( 'myplugin_save_meta_box_data', 'myplugin_meta_box_nonce'   );
$value = get_post_meta( $post->ID, '_my_meta_value_key', true );

echo '<label for="myplugin_new_field">';
_e( 'Description for this field', 'myplugin_textdomain' );
echo '</label> ';
echo '<input type="text" id="myplugin_new_field" name="myplugin_new_field" value="' . esc_attr( $value ) . '" size="25" />';
}

function myplugin_save_meta_box_data( $post_id ) {

if ( ! isset( $_POST['myplugin_meta_box_nonce'] ) ) {
    return;
}

// Verify that the nonce is valid.
if ( ! wp_verify_nonce( $_POST['myplugin_meta_box_nonce'], 'myplugin_save_meta_box_data' ) ) {
    return;
}

if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) {
    return;
}

// Check the user's permissions.
if ( isset( $_POST['post_type'] ) && 'page' == $_POST['post_type'] ) {

    if ( ! current_user_can( 'edit_page', $post_id ) ) {
        return;
    }

} else {

    if ( ! current_user_can( 'edit_post', $post_id ) ) {
        return;
    }
}

/* OK, it's safe for us to save the data now. */

// Make sure that it is set.
if ( ! isset( $_POST['myplugin_new_field'] ) ) {
    return;
}

// Sanitize user input.
$my_data = sanitize_text_field( $_POST['myplugin_new_field'] );

// Update the meta field in the database.
update_post_meta( $post_id, '_my_meta_value_key', $my_data );
}
add_action( 'save_post', 'myplugin_save_meta_box_data' );

如何使NSNumber接受选项

1 个答案: