How do I sort my x values for my graphview line graph in Android Studio using Java?

Question

I have a database that stores the values, a graphview line graph, and a dataseries. The current date is the X value and user inputs their current weight for the Y value. Once the user clicks add the data is supposed to get added to the graph however my array is not sorting. I keep getting error messages. Not sure if it's in the wrong place or if I'm missing something.

Error Message: The order of the values is not correct. X-Values have to be ordered ASC. First the lowest x value and at least the highest x value.

// Get graph from layout graph = (GraphView) findViewById(R.id.graph);

    UserDB = new DBHelper(this);
    sqLiteDatabase = UserDB.getWritableDatabase();
    dataSeries = new LineGraphSeries<>(new DataPoint[0]);

    insertDataToGraph();
    graph.addSeries(dataSeries);
    graph.getGridLabelRenderer().setNumHorizontalLabels(3);

    Calendar calendar = Calendar.getInstance();
    String dateTXT = sdf.format(calendar.getTime());
    date.setText(dateTXT);
    public void insertDataToGraph(){
    add.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            long xValue = new Date().getTime();
            int currentWeightTXT = parseInt(currentWeight.getText().toString());
            UserDB.insertToData(xValue, currentWeightTXT);
            dataSeries.resetData(grabData());

            graph.getGridLabelRenderer().setLabelFormatter(new DefaultLabelFormatter(){
                @Override
                public String formatLabel (double value, boolean isValueX){
                    if(isValueX){
                        return sdf.format(new Date((long) value));
                    }
                    else {
                        return super.formatLabel(value, false);
                    }
                }
            });
        }
    });
}
private DataPoint[] grabData(){
    String [] column = {"xValue", "currentWeight"};
    @SuppressLint("Recycle") Cursor cursor = sqLiteDatabase.query("Graph", column, null, null, null, null, null);
    DataPoint[] dataPoints = new DataPoint[cursor.getCount()];
    for(int i = 0; i < cursor.getCount(); i++){
        cursor.moveToNext();
        dataPoints[i] = new DataPoint(cursor.getLong(0), cursor.getInt(1));
    }
    Arrays.sort(dataPoints);
    return dataPoints;
}

Answer 1

There should be an argument called orderBy for the method query . You should set it to "xValue" . This way the database handles the sorting and you don't need to do it in your JAVA code.