10 Advanced Java for Bioinformatics, WS 17/18, D. Huson, October 26, 2017

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1 10 Advanced Java for Bioinformatics, WS 17/18, D. Huson, October 26, Controls Controls facilitate user input and in JavaFX they extend the class Control. controls: Here are some basic Button CheckBox ToggleButton RadioButton ListView ComboBox ChoiceBox 4.1 More buttons We have already seen Button and CheckBox. These, and other buttons, extend ButtonBase. A ToggleButton is very similar to a CheckBox; it has two states, selected or not, but cannot be indeterminate. In this example, buttons Lunch and Dinner have been selected, but not Breakfast: Use isselected() and setselected() to access the selected stated. RadioButton extends ToggleButton. A collection of radio buttons are mutually exclusive, you can only listen to one station at a time: All mutually exclusive buttons must be added to a single ToggleGroup: ToggleGroup group=new ToggleGroup();

2 Advanced Java for Bioinformatics, WS 17/18, D. Huson, October 26, group.gettoggles().addall(swr1button,swr2button,swr3button); Alternatively, use: swr1button.settogglegroup(group); ListView A ListView displays a list of objects. It is a generic class: class ListView<T>, where T specifies the type of entries, e.g. String. You can provide the list of items to display using this method: setitems(observablelist<t> list) Here, ObservableList extends java.util.list, so is a list that can be observed for changes. Nice: If you add or remove objects from the list programmatically then your ListView object will observe this and will update itself accordingly. You can create an instance of an observable list using the class javafx.collections.fxcollections. It provides a number of methods such as: static <E> ObservableList<E> observablearraylist(e... For example, this creates a new list with three elements: FXCollections.observableArrayList("Alice","Bob","Clive"); elements) A list view uses a selection model to maintain the selection state of items in the list. It is accessed using the method: MultipleSelectionModel<E> getselectionmodel(); By default, at most one element can be selected. To allow multiple selections, call setselectionmode(selectionmode mode) on the selection model, with mode either SelectionMode.MULTIPLE or SelectionMode.SINGLE. (We will look at the details of a selection model later.) In single mode, use the selection model method ReadOnlyObjectProperty<E> selecteditemproperty() to access the selected item. To react to changes of selection, add a listener to the returned property: addlistener((change,oldvalue,newvalue)->...); For example: addlistener((c,o,n)->system.err.println("change:"+o+"->"+n)); In multiple selection mode, use this method: ObservableList<E> getselecteditems(). This is a read-only list and cannot be used to change the selection state. Add a list changed listener to react to changes of the selection. As with most nodes in JavaFX, you can set the preferred size of a ListView like this: setprefheight(double h); setprefwidth(double w); ComboBox A ComboBox<T> displays one selection from a list of objects, has a dropdown methods for others and also allows editing.

3 12 Advanced Java for Bioinformatics, WS 17/18, D. Huson, October 26, 2017 You can use setitems() to set the list of items, or use getitems().add() or getitems().addall() to add items. Can use getvalue() to get the selection or use valueproperty() to get property to which we can add a listener to react to changes. Use setvalue() to set the selection programmatically, or can also bind the value property to some other property, as we will see later. Use seteditable() to allow or disable editing ChoiceBox A ChoiceBox is similar to a ComboBox, but is also like a group of radio buttons: 4.2 Tooltips The class Control (and thus any extension) has a method settooltip() which is used thus: Tooltip tip=new Tooltip("Quit the program"); quitbutton.settooltip(tip); Alternatively, use: Tooltip.install(quitButton,tip); The latter works for nodes that are not controls, too. 4.3 Properties In JavaFX, all variables of interest are implemented as properties. For example, a Button provides three methods to access the selection state of a button: isselected(), setselected() and selectedproperty(). Similarly, there are three methods to determine whether the button is disabled: isdisable(), setdisable() and disableproperty(). In these two examples, the third methods returns a BooleanProperty object. A Property provides methods to add listener for changes and we use this mechanism to react to user input. It also provides methods such as bind() that we can use to bind the property to some other property, as we will see later. 4.4 Text Controls Text controls allow entry, display and editing of text.

4 Advanced Java for Bioinformatics, WS 17/18, D. Huson, October 26, JavaFX provides: a TextField class for one line of text, a TextArea class for multiline text, and PasswordField for password input. All extend TextInputControl Text Field The basics of a TextField: It has a number of properties: text prompttext editable prefcolumncount anchor (read only) selectedtext (read only) caretposition (read only) User pressing the enter key generates an action event and you can use setonaction() to setup handling of such events. You can also use gettext() to get the entered text when needed. PasswordField is similar to TextField except that entered characters are not shown Text Area A TextArea is multiline version of a text field, so pressing enter will not generate an action but rather just change the line. It has the same properties as a TextField, and some additional ones, such as prefrowcount. This example uses a TextField for input and a TextArea for output:

5 14 Advanced Java for Bioinformatics, WS 17/18, D. Huson, October 26, Scroll pane Constrols such as ListView, ComboBox and TextArea display scrollbars as necessary. In addition, you can use a ScrollPane extends Node and place it inside the scene graph. A scroll pane has at most one child, which can be supplied using this method: setcontent(node content) There are a number of properties and methods for configuring a scroll pane, for example: setpannable(boolean enable) to enabling scrolling by dragging the mouse. 4.6 Slider A Slider shows a track and a thumb : Properties include: value, observe this to react to changes min and max showtickmarks showticklabels majortickunit minortickcount orientation (Orientation.HORIZONTAL or VERTICAL)

6 Advanced Java for Bioinformatics, WS 17/18, D. Huson, October 26, TreeView A TreeView is a powerful control for representing hiearchical data: This is a generic class with signature: public class TreeView<T>. The nodes of the displayed tree are instances of the class TreeItem<T>. Use setroot(treeitem<> root) to set the root node. TreeItem represents a node in the tree displayed by the TreeView, but does not extend Node. Properties: value: the value of the node children: the children of the node parent (read only) expanded: node can be collapsed or expanded TreeView has a selectionmode property that has value SelectionMode.SINGLE by default, but can also be set to SelectionMode.MULTIPLE. The selection state is represented by a selection model, which can be accessed using getselectionmodel(). Listening for selection changes is similar to ListView