javafx.scene.control.Label Maven / Gradle / Ivy
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*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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package javafx.scene.control;
import javafx.scene.control.skin.LabelSkin;
import com.sun.javafx.scene.NodeHelper;
import javafx.beans.property.ObjectProperty;
import javafx.beans.property.ObjectPropertyBase;
import javafx.beans.value.ChangeListener;
import javafx.css.StyleableProperty;
import javafx.scene.AccessibleRole;
import javafx.scene.Node;
/**
* Label is a non-editable text control. A Label is useful for displaying
* text that is required to fit within a specific space, and thus may need
* to use an ellipsis or truncation to size the string to fit. Labels also are
* useful in that they can have mnemonics which, if used, will send focus to
* the Control listed as the target of the labelFor property.
*
* Label sets focusTraversable to false.
*
*
* Example:
*
Label label = new Label("a label");
*
* 
*
* @since JavaFX 2.0
*/
public class Label extends Labeled {
/* *************************************************************************
* *
* Constructors *
* *
**************************************************************************/
/**
* Creates an empty label
*/
public Label() {
initialize();
}
/**
* Creates Label with supplied text.
* @param text null text is treated as the empty string
*/
public Label(String text) {
super(text);
initialize();
}
/**
* Creates a Label with the supplied text and graphic.
* @param text null text is treated as the empty string
* @param graphic a null graphic is acceptable
*/
public Label(String text, Node graphic) {
super(text, graphic);
initialize();
}
private void initialize() {
getStyleClass().setAll("label");
setAccessibleRole(AccessibleRole.TEXT);
// Labels are not focus traversable, unlike most other UI Controls.
// focusTraversable is styleable through css. Calling setFocusTraversable
// makes it look to css like the user set the value and css will not
// override. Initializing focusTraversable by calling set on the
// CssMetaData ensures that css will be able to override the value.
((StyleableProperty)focusTraversableProperty()).applyStyle(null, Boolean.FALSE);
}
/* *************************************************************************
* *
* Properties *
* *
**************************************************************************/
private ChangeListener mnemonicStateListener = (observable, oldValue, newValue) -> {
NodeHelper.showMnemonicsProperty(Label.this).setValue(newValue);
};
/**
* A Label can act as a label for a different Control or
* Node. This is used for Mnemonics and Accelerator parsing.
* This allows setting of the target Node.
* @return the Node that this label is to be associated with
*/
public ObjectProperty labelForProperty() {
if (labelFor == null) {
labelFor = new ObjectPropertyBase<>() {
Node oldValue = null;
@Override protected void invalidated() {
if (oldValue != null) {
NodeHelper.getNodeAccessor().setLabeledBy(oldValue, null);
NodeHelper.showMnemonicsProperty(oldValue).removeListener(mnemonicStateListener);
}
final Node node = get();
if (node != null) {
NodeHelper.getNodeAccessor().setLabeledBy(node, Label.this);
NodeHelper.showMnemonicsProperty(node).addListener(mnemonicStateListener);
NodeHelper.setShowMnemonics(Label.this, NodeHelper.isShowMnemonics(node));
} else {
NodeHelper.setShowMnemonics(Label.this, false);
}
oldValue = node;
}
@Override public Object getBean() {
return Label.this;
}
@Override public String getName() {
return "labelFor";
}
};
}
return labelFor;
}
private ObjectProperty labelFor;
public final void setLabelFor(Node value) { labelForProperty().setValue(value); }
public final Node getLabelFor() { return labelFor == null ? null : labelFor.getValue(); }
/* *************************************************************************
* *
* Methods *
* *
**************************************************************************/
/** {@inheritDoc} */
@Override protected Skin createDefaultSkin() {
return new LabelSkin(this);
}
/* *************************************************************************
* *
* CSS Support *
* *
**************************************************************************/
/**
* Returns the initial focus traversable state of this control, for use
* by the JavaFX CSS engine to correctly set its initial value. This method
* is overridden as by default UI controls have focus traversable set to true,
* but that is not appropriate for this control.
*
* @since 9
*/
@Override protected Boolean getInitialFocusTraversable() {
return Boolean.FALSE;
}
}
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