TextField type to Show Button in javafx - javafx-2

Question

I am trying Show a Button on TextField look like Windows 8 Metro theme in javafx.
If TextField is empty button is invisible otherwise button show.
In this stage i'm little close to success. i use this code to make it.
#FXML
private TextField tfMyName;//fx:id="tfMyName"
#FXML
private Button btnClear;//fx:id="btnClear"
#Override
public void initialize(URL url, ResourceBundle rb) {
clearTextFieldByButton(tfMyName, btnClear);
}
public void clearTextFieldByButton(TextField value, Button btn){
btn.setVisible(false);
value.setOnKeyTyped(new EventHandler<KeyEvent>(){
#Override
public void handle(KeyEvent event) {
if ((value.textProperty().get().length() < 0) || (value.textProperty().get().equals(""))) {
btn.setVisible(false);
} else if (value.textProperty().get().length() > -1 || (!value.textProperty().get().equals(""))) {
btn.setVisible(true);
}
}
});
btn.setOnAction(new EventHandler<ActionEvent>() {
#Override
public void handle(ActionEvent event) {
tfMyName.clear();
btn.setVisible(false);
tfMyName.requestFocus();
}
});
Using this code by default button is invisible but the button is only visible when i type more then one Characters.
But i need if anything input into the TextField to Button show.
But when i remove the condition under KeyEvent replace by
value.setOnKeyTyped(new EventHandler<KeyEvent>(){
#Override
public void handle(KeyEvent event) {
btn.setVisible(true);
}
});
Then btn show if any character input into the TextField

Answer 1

You may also prefer to use JavaFX binding mechanism:
#Override
public void start( final Stage primaryStage )
{
TextField textfield = new TextField();
Button button = new Button( "my button" );
button.visibleProperty().bind( textfield.textProperty().isEmpty().not() );
final Scene scene = new Scene( new HBox( button, textfield ), 800, 600 );
primaryStage.setScene( scene );
primaryStage.show();
}
The actual problem in your code:
You have attached a listener to field when "OnKeyTyped", at this stage the newly typed text is not appended to the textfield's text value so your if-else condition will not see it. Instead, the correct way should be attaching the listener on "OnKeyReleased".

Answer 2

Add a listener to the textProperty() of the TextField. Check if the value is empty, hide the button else show it. It will be called whenever a character is added or removed from the textfield.
Here is a MCVE, you can just add the listener to the initialize method of the controller.
import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TextField;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
public class HideButtonOnTextEntered extends Application {
#Override
public void start(Stage stage) {
TextField textField = new TextField();
Button button = new Button("Button");
button.setVisible(false);
VBox root = new VBox(20, textField, button);
root.setAlignment(Pos.CENTER);
Scene scene = new Scene(root, 200, 200);
stage.setScene(scene);
stage.show();
textField.textProperty().addListener((ov, oldValue, newValue) -> {
if (newValue.isEmpty()) {
button.setVisible(false);
} else {
button.setVisible(true);
}
});
}
public static void main(String[] args) {
launch(args);
}
}