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.