Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like WP_Screen often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use WP_Screen, and based on these observations, apply Extract Interface, too.
1 | <?php |
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15 | final class WP_Screen { |
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16 | /** |
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17 | * Any action associated with the screen. 'add' for *-add.php and *-new.php screens. Empty otherwise. |
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18 | * |
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19 | * @since 3.3.0 |
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20 | * @var string |
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21 | * @access public |
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22 | */ |
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23 | public $action; |
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24 | |||
25 | /** |
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26 | * The base type of the screen. This is typically the same as $id but with any post types and taxonomies stripped. |
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27 | * For example, for an $id of 'edit-post' the base is 'edit'. |
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28 | * |
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29 | * @since 3.3.0 |
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30 | * @var string |
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31 | * @access public |
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32 | */ |
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33 | public $base; |
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34 | |||
35 | /** |
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36 | * The number of columns to display. Access with get_columns(). |
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37 | * |
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38 | * @since 3.4.0 |
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39 | * @var int |
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40 | * @access private |
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41 | */ |
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42 | private $columns = 0; |
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43 | |||
44 | /** |
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45 | * The unique ID of the screen. |
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46 | * |
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47 | * @since 3.3.0 |
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48 | * @var string |
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49 | * @access public |
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50 | */ |
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51 | public $id; |
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52 | |||
53 | /** |
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54 | * Which admin the screen is in. network | user | site | false |
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55 | * |
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56 | * @since 3.5.0 |
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57 | * @var string |
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58 | * @access protected |
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59 | */ |
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60 | protected $in_admin; |
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61 | |||
62 | /** |
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63 | * Whether the screen is in the network admin. |
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64 | * |
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65 | * Deprecated. Use in_admin() instead. |
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66 | * |
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67 | * @since 3.3.0 |
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68 | * @deprecated 3.5.0 |
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69 | * @var bool |
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70 | * @access public |
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71 | */ |
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72 | public $is_network; |
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73 | |||
74 | /** |
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75 | * Whether the screen is in the user admin. |
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76 | * |
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77 | * Deprecated. Use in_admin() instead. |
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78 | * |
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79 | * @since 3.3.0 |
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80 | * @deprecated 3.5.0 |
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81 | * @var bool |
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82 | * @access public |
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83 | */ |
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84 | public $is_user; |
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85 | |||
86 | /** |
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87 | * The base menu parent. |
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88 | * This is derived from $parent_file by removing the query string and any .php extension. |
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89 | * $parent_file values of 'edit.php?post_type=page' and 'edit.php?post_type=post' have a $parent_base of 'edit'. |
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90 | * |
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91 | * @since 3.3.0 |
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92 | * @var string |
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93 | * @access public |
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94 | */ |
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95 | public $parent_base; |
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96 | |||
97 | /** |
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98 | * The parent_file for the screen per the admin menu system. |
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99 | * Some $parent_file values are 'edit.php?post_type=page', 'edit.php', and 'options-general.php'. |
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100 | * |
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101 | * @since 3.3.0 |
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102 | * @var string |
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103 | * @access public |
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104 | */ |
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105 | public $parent_file; |
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106 | |||
107 | /** |
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108 | * The post type associated with the screen, if any. |
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109 | * The 'edit.php?post_type=page' screen has a post type of 'page'. |
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110 | * The 'edit-tags.php?taxonomy=$taxonomy&post_type=page' screen has a post type of 'page'. |
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111 | * |
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112 | * @since 3.3.0 |
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113 | * @var string |
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114 | * @access public |
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115 | */ |
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116 | public $post_type; |
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117 | |||
118 | /** |
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119 | * The taxonomy associated with the screen, if any. |
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120 | * The 'edit-tags.php?taxonomy=category' screen has a taxonomy of 'category'. |
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121 | * @since 3.3.0 |
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122 | * @var string |
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123 | * @access public |
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124 | */ |
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125 | public $taxonomy; |
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126 | |||
127 | /** |
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128 | * The help tab data associated with the screen, if any. |
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129 | * |
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130 | * @since 3.3.0 |
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131 | * @var array |
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132 | * @access private |
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133 | */ |
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134 | private $_help_tabs = array(); |
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135 | |||
136 | /** |
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137 | * The help sidebar data associated with screen, if any. |
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138 | * |
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139 | * @since 3.3.0 |
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140 | * @var string |
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141 | * @access private |
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142 | */ |
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143 | private $_help_sidebar = ''; |
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144 | |||
145 | /** |
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146 | * The accessible hidden headings and text associated with the screen, if any. |
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147 | * |
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148 | * @since 4.4.0 |
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149 | * @access private |
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150 | * @var array |
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151 | */ |
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152 | private $_screen_reader_content = array(); |
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153 | |||
154 | /** |
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155 | * Stores old string-based help. |
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156 | * |
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157 | * @static |
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158 | * @access private |
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159 | * |
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160 | * @var array |
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161 | */ |
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162 | private static $_old_compat_help = array(); |
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163 | |||
164 | /** |
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165 | * The screen options associated with screen, if any. |
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166 | * |
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167 | * @since 3.3.0 |
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168 | * @var array |
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169 | * @access private |
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170 | */ |
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171 | private $_options = array(); |
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172 | |||
173 | /** |
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174 | * The screen object registry. |
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175 | * |
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176 | * @since 3.3.0 |
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177 | * |
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178 | * @static |
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179 | * @access private |
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180 | * |
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181 | * @var array |
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182 | */ |
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183 | private static $_registry = array(); |
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184 | |||
185 | /** |
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186 | * Stores the result of the public show_screen_options function. |
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187 | * |
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188 | * @since 3.3.0 |
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189 | * @var bool |
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190 | * @access private |
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191 | */ |
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192 | private $_show_screen_options; |
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193 | |||
194 | /** |
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195 | * Stores the 'screen_settings' section of screen options. |
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196 | * |
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197 | * @since 3.3.0 |
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198 | * @var string |
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199 | * @access private |
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200 | */ |
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201 | private $_screen_settings; |
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202 | |||
203 | /** |
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204 | * Fetches a screen object. |
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205 | * |
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206 | * @since 3.3.0 |
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207 | * @access public |
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208 | * |
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209 | * @static |
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210 | * |
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211 | * @global string $hook_suffix |
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212 | * |
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213 | * @param string|WP_Screen $hook_name Optional. The hook name (also known as the hook suffix) used to determine the screen. |
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214 | * Defaults to the current $hook_suffix global. |
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215 | * @return WP_Screen Screen object. |
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216 | */ |
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217 | public static function get( $hook_name = '' ) { |
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372 | |||
373 | /** |
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374 | * Makes the screen object the current screen. |
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375 | * |
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376 | * @see set_current_screen() |
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377 | * @since 3.3.0 |
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378 | * |
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379 | * @global WP_Screen $current_screen |
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380 | * @global string $taxnow |
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381 | * @global string $typenow |
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382 | */ |
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383 | public function set_current_screen() { |
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398 | |||
399 | /** |
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400 | * Constructor |
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401 | * |
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402 | * @since 3.3.0 |
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403 | * @access private |
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404 | */ |
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405 | private function __construct() {} |
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406 | |||
407 | /** |
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408 | * Indicates whether the screen is in a particular admin |
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409 | * |
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410 | * @since 3.5.0 |
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411 | * |
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412 | * @param string $admin The admin to check against (network | user | site). |
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413 | * If empty any of the three admins will result in true. |
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414 | * @return bool True if the screen is in the indicated admin, false otherwise. |
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415 | */ |
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416 | public function in_admin( $admin = null ) { |
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422 | |||
423 | /** |
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424 | * Sets the old string-based contextual help for the screen for backward compatibility. |
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425 | * |
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426 | * @since 3.3.0 |
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427 | * |
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428 | * @static |
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429 | * |
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430 | * @param WP_Screen $screen A screen object. |
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431 | * @param string $help Help text. |
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432 | */ |
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433 | public static function add_old_compat_help( $screen, $help ) { |
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436 | |||
437 | /** |
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438 | * Set the parent information for the screen. |
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439 | * This is called in admin-header.php after the menu parent for the screen has been determined. |
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440 | * |
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441 | * @since 3.3.0 |
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442 | * |
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443 | * @param string $parent_file The parent file of the screen. Typically the $parent_file global. |
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444 | */ |
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445 | public function set_parentage( $parent_file ) { |
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450 | |||
451 | /** |
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452 | * Adds an option for the screen. |
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453 | * Call this in template files after admin.php is loaded and before admin-header.php is loaded to add screen options. |
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454 | * |
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455 | * @since 3.3.0 |
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456 | * |
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457 | * @param string $option Option ID |
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458 | * @param mixed $args Option-dependent arguments. |
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459 | */ |
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460 | public function add_option( $option, $args = array() ) { |
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463 | |||
464 | /** |
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465 | * Remove an option from the screen. |
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466 | * |
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467 | * @since 3.8.0 |
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468 | * |
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469 | * @param string $option Option ID. |
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470 | */ |
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471 | public function remove_option( $option ) { |
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474 | |||
475 | /** |
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476 | * Remove all options from the screen. |
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477 | * |
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478 | * @since 3.8.0 |
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479 | */ |
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480 | public function remove_options() { |
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483 | |||
484 | /** |
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485 | * Get the options registered for the screen. |
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486 | * |
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487 | * @since 3.8.0 |
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488 | * |
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489 | * @return array Options with arguments. |
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490 | */ |
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491 | public function get_options() { |
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494 | |||
495 | /** |
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496 | * Gets the arguments for an option for the screen. |
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497 | * |
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498 | * @since 3.3.0 |
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499 | * |
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500 | * @param string $option Option name. |
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501 | * @param string $key Optional. Specific array key for when the option is an array. |
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502 | * Default false. |
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503 | * @return string The option value if set, null otherwise. |
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504 | */ |
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505 | public function get_option( $option, $key = false ) { |
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515 | |||
516 | /** |
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517 | * Gets the help tabs registered for the screen. |
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518 | * |
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519 | * @since 3.4.0 |
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520 | * @since 4.4.0 Help tabs are ordered by their priority. |
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521 | * |
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522 | * @return array Help tabs with arguments. |
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523 | */ |
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524 | public function get_help_tabs() { |
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547 | |||
548 | /** |
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549 | * Gets the arguments for a help tab. |
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550 | * |
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551 | * @since 3.4.0 |
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552 | * |
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553 | * @param string $id Help Tab ID. |
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554 | * @return array Help tab arguments. |
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555 | */ |
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556 | public function get_help_tab( $id ) { |
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561 | |||
562 | /** |
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563 | * Add a help tab to the contextual help for the screen. |
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564 | * Call this on the load-$pagenow hook for the relevant screen. |
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565 | * |
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566 | * @since 3.3.0 |
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567 | * @since 4.4.0 The `$priority` argument was added. |
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568 | * |
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569 | * @param array $args { |
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570 | * Array of arguments used to display the help tab. |
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571 | * |
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572 | * @type string $title Title for the tab. Default false. |
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573 | * @type string $id Tab ID. Must be HTML-safe. Default false. |
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574 | * @type string $content Optional. Help tab content in plain text or HTML. Default empty string. |
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575 | * @type string $callback Optional. A callback to generate the tab content. Default false. |
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576 | * @type int $priority Optional. The priority of the tab, used for ordering. Default 10. |
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577 | * } |
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578 | */ |
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579 | public function add_help_tab( $args ) { |
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598 | |||
599 | /** |
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600 | * Removes a help tab from the contextual help for the screen. |
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601 | * |
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602 | * @since 3.3.0 |
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603 | * |
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604 | * @param string $id The help tab ID. |
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605 | */ |
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606 | public function remove_help_tab( $id ) { |
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609 | |||
610 | /** |
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611 | * Removes all help tabs from the contextual help for the screen. |
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612 | * |
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613 | * @since 3.3.0 |
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614 | */ |
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615 | public function remove_help_tabs() { |
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618 | |||
619 | /** |
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620 | * Gets the content from a contextual help sidebar. |
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621 | * |
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622 | * @since 3.4.0 |
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623 | * |
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624 | * @return string Contents of the help sidebar. |
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625 | */ |
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626 | public function get_help_sidebar() { |
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629 | |||
630 | /** |
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631 | * Add a sidebar to the contextual help for the screen. |
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632 | * Call this in template files after admin.php is loaded and before admin-header.php is loaded to add a sidebar to the contextual help. |
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633 | * |
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634 | * @since 3.3.0 |
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635 | * |
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636 | * @param string $content Sidebar content in plain text or HTML. |
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637 | */ |
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638 | public function set_help_sidebar( $content ) { |
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641 | |||
642 | /** |
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643 | * Gets the number of layout columns the user has selected. |
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644 | * |
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645 | * The layout_columns option controls the max number and default number of |
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646 | * columns. This method returns the number of columns within that range selected |
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647 | * by the user via Screen Options. If no selection has been made, the default |
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648 | * provisioned in layout_columns is returned. If the screen does not support |
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649 | * selecting the number of layout columns, 0 is returned. |
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650 | * |
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651 | * @since 3.4.0 |
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652 | * |
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653 | * @return int Number of columns to display. |
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654 | */ |
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655 | public function get_columns() { |
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658 | |||
659 | /** |
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660 | * Get the accessible hidden headings and text used in the screen. |
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661 | * |
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662 | * @since 4.4.0 |
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663 | * |
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664 | * @see set_screen_reader_content() For more information on the array format. |
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665 | * |
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666 | * @return array An associative array of screen reader text strings. |
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667 | */ |
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668 | public function get_screen_reader_content() { |
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671 | |||
672 | /** |
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673 | * Get a screen reader text string. |
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674 | * |
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675 | * @since 4.4.0 |
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676 | * |
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677 | * @param string $key Screen reader text array named key. |
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678 | * @return string Screen reader text string. |
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679 | */ |
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680 | public function get_screen_reader_text( $key ) { |
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686 | |||
687 | /** |
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688 | * Add accessible hidden headings and text for the screen. |
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689 | * |
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690 | * @since 4.4.0 |
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691 | * |
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692 | * @param array $content { |
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693 | * An associative array of screen reader text strings. |
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694 | * |
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695 | * @type string $heading_views Screen reader text for the filter links heading. |
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696 | * Default 'Filter items list'. |
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697 | * @type string $heading_pagination Screen reader text for the pagination heading. |
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698 | * Default 'Items list navigation'. |
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699 | * @type string $heading_list Screen reader text for the items list heading. |
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700 | * Default 'Items list'. |
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701 | * } |
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702 | */ |
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703 | public function set_screen_reader_content( $content = array() ) { |
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713 | |||
714 | /** |
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715 | * Remove all the accessible hidden headings and text for the screen. |
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716 | * |
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717 | * @since 4.4.0 |
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718 | */ |
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719 | public function remove_screen_reader_content() { |
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722 | |||
723 | /** |
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724 | * Render the screen's help section. |
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725 | * |
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726 | * This will trigger the deprecated filters for backward compatibility. |
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727 | * |
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728 | * @since 3.3.0 |
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729 | * |
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730 | * @global string $screen_layout_columns |
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731 | */ |
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732 | public function render_screen_meta() { |
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902 | |||
903 | /** |
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904 | * |
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905 | * @global array $wp_meta_boxes |
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906 | * |
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907 | * @return bool |
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908 | */ |
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909 | public function show_screen_options() { |
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963 | |||
964 | /** |
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965 | * Render the screen options tab. |
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966 | * |
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967 | * @since 3.3.0 |
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968 | * |
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969 | * @param array $options { |
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970 | * @type bool $wrap Whether the screen-options-wrap div will be included. Defaults to true. |
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971 | * } |
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972 | */ |
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973 | public function render_screen_options( $options = array() ) { |
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1018 | |||
1019 | /** |
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1020 | * Render the meta boxes preferences. |
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1021 | * |
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1022 | * @since 4.4.0 |
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1023 | * |
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1024 | * @global array $wp_meta_boxes |
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1025 | */ |
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1026 | public function render_meta_boxes_preferences() { |
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1056 | |||
1057 | /** |
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1058 | * Render the list table columns preferences. |
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1059 | * |
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1060 | * @since 4.4.0 |
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1061 | */ |
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1062 | public function render_list_table_columns_preferences() { |
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1101 | |||
1102 | /** |
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1103 | * Render the option for number of columns on the page |
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1104 | * |
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1105 | * @since 3.3.0 |
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1106 | */ |
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1107 | public function render_screen_layout() { |
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1130 | |||
1131 | /** |
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1132 | * Render the items per page option |
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1133 | * |
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1134 | * @since 3.3.0 |
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1135 | */ |
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1136 | public function render_per_page_options() { |
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1194 | |||
1195 | /** |
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1196 | * Render the list table view mode preferences. |
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1197 | * |
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1198 | * @since 4.4.0 |
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1199 | * |
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1200 | * @global string $mode List table view mode. |
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1201 | */ |
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1202 | public function render_view_mode() { |
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1244 | |||
1245 | /** |
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1246 | * Render screen reader text. |
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1247 | * |
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1248 | * @since 4.4.0 |
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1249 | * |
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1250 | * @param string $key The screen reader text array named key. |
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1251 | * @param string $tag Optional. The HTML tag to wrap the screen reader text. Default h2. |
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1252 | */ |
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1253 | public function render_screen_reader_content( $key = '', $tag = 'h2' ) { |
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1260 | } |
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1261 |