JavaFX LineChart-清除图表中的数据

Question

i have problem with remove data from line chart. I wrote a program drawing graphs that after the action click on the button completes the chart data.

dataSeries1.getData().removeAll(); <- doesn't work.

Code:

 NumberAxis xAxis = new NumberAxis();
    xAxis.setLabel("Oś Y");
    NumberAxis yAxis = new NumberAxis();
    yAxis.setLabel("Oś X");
    final LineChart lineChart = new LineChart(xAxis, yAxis);
    final XYChart.Series dataSeries1 = new XYChart.Series();

    lineChart.setCreateSymbols(false);
    lineChart.getData().add(dataSeries1);

Button action:

 btn.setOnAction(new EventHandler<ActionEvent>() {
        @Override
        public void handle(ActionEvent event) {

            int lewy = Integer.parseInt(kresLewy.getText());
            int prawy = Integer.parseInt(kresPrawy.getText());
            String rownanie = field.getText();

            try {

                String tekst = lewy + "; " + prawy + "; " + rownanie;

                StringReader tekstReader = new StringReader(tekst);

                parsery.interpreter.parser parser_obj
                        = new parsery.interpreter.parser(new parsery.interpreter.MyLexer(tekstReader));

                Object result = parser_obj.parse().value;

                String sWynik = result.toString();

                ZmiennaX zX = new ZmiennaX();
                ArrayList<Double> xArr = new ArrayList<Double>();
                for (double i = lewy; i <= prawy + 0.001; i = i + zX.getDokladnosc()) // +0.001 dla bledow zaokraglenia
                {
                    xArr.add(zX.round2(i));
                }
                String sX = xArr.toString();
                String wartosciX = sX.substring(1, sX.length() - 1);
                String wartosciY = sWynik.substring(1, sWynik.length() - 1);

                String XbezSpacji = wartosciX.replace(" ", "");
                String YbezSpacji = wartosciY.replace(" ", "");

                String[] splitX = XbezSpacji.split(",");
                String[] splitY = YbezSpacji.split(",");
                dataSeries1.getData().removeAll();

                for(int i=0; i<splitX.length; i++){
                double x = Double.parseDouble(splitX[i]);
                double y = Double.parseDouble(splitY[i]);
                dataSeries1.getData().add(new XYChart.Data(x, y));
                }

            } catch (Exception e) {
                System.out.println("Podczs obliczenia wystapil blad. (" + e.getMessage() + ")");
            } catch (Error error) {
                System.out.println("Podczs obliczenia wystapil blad. (" + error.getMessage() + ")");
            }
        }
    });

Can anyone help me to remove data after drawing a new chart?

Answer 1

removeAll requires elements to be removed passed in its parameter. Since you provided none - nothing gets removed:

dataSeries1.getData().removeAll();

You want to use clear() instead in the line above.

public void clear()

Removes all of the elements from this list (optional operation). The list will be empty after this call returns.

Answer 2

You can use Collections.singleton to remove all data:

dataSeries1.getData().removeAll(Collections.singleton(barChart.getData().setAll()));

See Oracle documentation for Collections.singleton https://docs.oracle.com/javase/7/docs/api/java/util/Collections.html