iOS plugin File, checkFile - plugin_not_installed

Installed this plugin:

I save the file in this way

this.file.writeFile (this.file.dataDirectory, ‘mywins.xml’, xml, {replace: true}).
then () => {alert (‘save good’);}). catch ((error) => {alert (‘not saved’ + error);});

Errors do not show, but when I try to check the existence of a file through checkFile:

this.file.checkFile (this.file.dataDirectory, ‘mywins.xml’). then (function (success) {alert (succes);}, function (error) {alert (error);});

Indicates an error: plugin_not_installed

Android works completely

Solved the problem, checkFile was in the designer. Has added a ready platform in the designer and earned