placeholder support added for text and textarea

Author: Md. Kowsar Hossain

src/class.settings-api.php

@@ -132,6 +132,7 @@ function admin_init() {
                     'std'               => isset( $option['default'] ) ? $option['default'] : '',
                     'sanitize_callback' => isset( $option['sanitize_callback'] ) ? $option['sanitize_callback'] : '',
                     'type'              => $type,
+                    'placeholder'       => isset( $option['placeholder'] ) ? $option['placeholder'] : '',
                 );
 
                 add_settings_field( $section . '[' . $option['name'] . ']', $option['label'], array( $this, 'callback_' . $type ), $section, $section, $args );
@@ -166,12 +167,13 @@ public function get_field_description( $args ) {
      */
     function callback_text( $args ) {
 
-        $value = esc_attr( $this->get_option( $args['id'], $args['section'], $args['std'] ) );
-        $size  = isset( $args['size'] ) && !is_null( $args['size'] ) ? $args['size'] : 'regular';
-        $type  = isset( $args['type'] ) ? $args['type'] : 'text';
+        $value       = esc_attr( $this->get_option( $args['id'], $args['section'], $args['std'] ) );
+        $size        = isset( $args['size'] ) && !is_null( $args['size'] ) ? $args['size'] : 'regular';
+        $type        = isset( $args['type'] ) ? $args['type'] : 'text';
+        $placeholder = empty( $args['placeholder'] ) ? '' : ' placeholder="'.$args['placeholder'].'"';
 
-        $html  = sprintf( '<input type="%1$s" class="%2$s-text" id="%3$s[%4$s]" name="%3$s[%4$s]" value="%5$s"/>', $type, $size, $args['section'], $args['id'], $value );
-        $html  .= $this->get_field_description( $args );
+        $html        = sprintf( '<input type="%1$s" class="%2$s-text" id="%3$s[%4$s]" name="%3$s[%4$s]" value="%5$s"%6$s/>', $type, $size, $args['section'], $args['id'], $value, $placeholder );
+        $html       .= $this->get_field_description( $args );
 
         echo $html;
     }
@@ -286,11 +288,12 @@ function callback_select( $args ) {
      */
     function callback_textarea( $args ) {
 
-        $value = esc_textarea( $this->get_option( $args['id'], $args['section'], $args['std'] ) );
-        $size  = isset( $args['size'] ) && !is_null( $args['size'] ) ? $args['size'] : 'regular';
+        $value       = esc_textarea( $this->get_option( $args['id'], $args['section'], $args['std'] ) );
+        $size        = isset( $args['size'] ) && !is_null( $args['size'] ) ? $args['size'] : 'regular';
+        $placeholder = empty( $args['placeholder'] ) ? '' : ' placeholder="'.$args['placeholder'].'"';
 
-        $html  = sprintf( '<textarea rows="5" cols="55" class="%1$s-text" id="%2$s[%3$s]" name="%2$s[%3$s]">%4$s</textarea>', $size, $args['section'], $args['id'], $value );
-        $html  .= $this->get_field_description( $args );
+        $html        = sprintf( '<textarea rows="5" cols="55" class="%1$s-text" id="%2$s[%3$s]" name="%2$s[%3$s]"%4$s>%5$s</textarea>', $size, $args['section'], $args['id'], $placeholder, $value );
+        $html        .= $this->get_field_description( $args );
 
         echo $html;
     }