Widget Title is not saving in backend

Question

I have developed a widget to show latest news. The widget functionality is working correctly but the problem is the Widget title is not saving in backend. What is the right way to do it?

class infotravel_news_list_widget extends WP_Widget {
    public function __construct() {
        parent::__construct( false, $name = __( 'Latest News', 'infotravel' ) );
    }

    public function form( $instance ) {

        $defaults = array(
                'title' => '',
        );

        extract( wp_parse_args( array( $instance, $defaults ) ) );

        // Widget title ?>
        <p>
            <label for="<?php echo esc_attr( $this->get_field_id( 'title' ) ); ?>"><?php _e( 'Title', 'infotravel' ); ?></label>
            <input class="widefat" id="<?php echo esc_attr( $this->get_field_id( 'title' ) ); ?>" name="<?php echo esc_attr( $this->get_field_name( 'title' ) ); ?>" type="text" value="<?php echo esc_attr( $defaults['title'] ); ?>" />
        </p>

        <?php
    }

    public function update( $new_instance, $old_instance ) {
        $instance = $old_instance;
        $instance['title'] = isset( $new_instance['title'] ) ? wp_strip_all_tags( $new_instance['title'] ) : '';

        return $instance;
    }

    public function widget( $args, $instance ) {
        $news_args = array(
            'post_type'      => 'infotravel_news',
            'posts_per_page' => 5,
            'post_status'    => 'publish',
            'orderby'        => 'post_date',
            'order'          => 'desc'
        );
        $query = new WP_Query( $news_args );

        if( $query -> have_posts() ) :
            while( $query -> have_posts() ) : $query -> the_post(); ?>
                <h3><?php the_title(); ?></h3>
            <?php
            endwhile;
        endif;
    ?>

    <?php }
}

add_action( 'widgets_init', function(){
    register_widget( 'infotravel_news_list_widget' );
} );

Answer 1

It's because you're always outputting the default value into the input, regardless of what the saved value is:

<input class="widefat" id="<?php echo esc_attr( $this->get_field_id( 'title' ) ); ?>" name="<?php echo esc_attr( $this->get_field_name( 'title' ) ); ?>" type="text" value="<?php echo esc_attr( $defaults['title'] ); ?>" />

Specifically:

value="<?php echo esc_attr( $defaults['title'] ); ?>"

$defaults['title'] is always going to be an empty string. The saved title is inside $instance['title'], and, because of this line:

extract( wp_parse_args( array( $instance, $defaults ) ) );

It is also inside a variable called $title. This isn't immediately obvious, which is why using extract() like this is bad practice.

I suggest either setting the variables explicitly:

$title = isset( $instance['title'] ) ? $instance['title'] : $defaults['title']; 

In which case the value should be output like so:

value="<?php echo esc_attr( $title ); ?>"

Or putting the result of wp_parse_args() back into $instance:

public function form( $instance ) {
    $defaults = array(
        'title' => '',
    );

    $instance = wp_parse_args( array( $instance, $defaults ) );

    // ...etc.
}

In which case the value should be output like so:

value="<?php echo esc_attr( $instance['title'] ); ?>"