java - Define custom Comparator for JavaFX TableView Column rendered as SimpleObjectProperty<ImageView> -

i have table has different columns , signature of 1 want add custom comporator :

@fxml private tablecolumn<media,simpleobjectproperty<imageview>> hasbeenplayed; 

so column rendered imageview . has 2 possible states , either imageview have null image or imageview have image , specific 1 have defined .

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so want sorting based on if imageview has null image , if imageview has image , made below comparator reports error don't know why...

hasbeenplayed.setcomparator( new comparator<simpleobjectproperty<imageview>>() {    @override    public int compare(simpleobjectproperty<imageview> o1 , simpleobjectproperty<imageview> o2) {       if (o1.get().getimage() == o2.get().getimage())          return 0;       return -1;    } }); 

i should use lambda expression above , added in way more obvious trying achieve.

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the error getting ..

exception in thread "javafx application thread" java.lang.classcastexception:   javafx.scene.image.imageview cannot cast javafx.beans.property.simpleobjectproperty 

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as james_d requested on comments:

cell value factory:

hasbeenplayed.setcellvaluefactory(new propertyvaluefactory<>("hasbeenplayed")); 

part of model media:

public abstract class media {   .....   /** has been played. */  private simpleobjectproperty<imageview> hasbeenplayed;   .....   /**  * checks been played property.  *  * @return simple object property  */  public simpleobjectproperty<imageview> hasbeenplayedproperty() {     return hasbeenplayed;  } 

}

there multiple issues code.

first of you're putting ui elements in item class, should avoid. name of column hints @ displayed property have 2 states. boolean property more appropriate.

use custom cellfactory display image.

furthermore according error message real type of column should tablecolumn<media, imageview>.

also you're violating contract of comparator making non-symetric.

you have ensure following fulfilled:

if comparator.compare(a, b) < 0 comparator.compare(b, a) > 0. in case not fulfilled unless imageviews contain same image (or contain null).

modify code in addition making property boolean property:

@fxml private tablecolumn<media, boolean> hasbeenplayed; 

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hasbeenplayed.setcomparator((v1, v2) -> boolean.compare(v1, v2)); 

or alternatively

hasbeenplayed.setcomparator((v1, v2) -> -boolean.compare(v1, v2)); 

and add following initialize method of controller

final image playedimage = new image(...);  hasbeenplayed.setcellfactory(col -> new tablecell<media, boolean>() {     private final imageview image = new imageview();      {         setgraphic(image);         image.setfitwidth(playedimage.getwidth());         image.setfitheight(playedimage.getheight());     }      @override     protected void updateitem(boolean item, boolean empty) {          super.updateitem(item, empty);           // set image according played state          image.setimage(item != null && item ? playedimage : null);     } });